U.S. patent application number 13/838917 was filed with the patent office on 2013-10-17 for poly(acrylic acid) from bio-based acrylic acid and its derivatives.
This patent application is currently assigned to THE PROCTER & GAMBLE COMPANY. The applicant listed for this patent is THE PROCTER & GAMBLE COMPANY. Invention is credited to Dimitris Ioannis Collias, Peter Dziezok, Jane Ellen Godlewski, Axel Meyer, Juan Estaban Velasquez, Janette Villalobos.
Application Number | 20130273384 13/838917 |
Document ID | / |
Family ID | 49325381 |
Filed Date | 2013-10-17 |
United States Patent
Application |
20130273384 |
Kind Code |
A1 |
Godlewski; Jane Ellen ; et
al. |
October 17, 2013 |
Poly(Acrylic Acid) From Bio-Based Acrylic Acid And Its
Derivatives
Abstract
Bio-based glacial acrylic acid, produced from hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof and
having impurities of hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof, is polymerized to poly(acrylic
acid) or superabsorbent polymer using the same processes as
petroleum-derived glacial acrylic acid.
Inventors: |
Godlewski; Jane Ellen;
(Loveland, OH) ; Villalobos; Janette; (Cincinnati,
OH) ; Collias; Dimitris Ioannis; (Mason, OH) ;
Meyer; Axel; (Frankfurt am Main, DE) ; Dziezok;
Peter; (Hochheim, DE) ; Velasquez; Juan Estaban;
(Cincinnati, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE PROCTER & GAMBLE COMPANY |
Cincinnati |
OH |
US |
|
|
Assignee: |
THE PROCTER & GAMBLE
COMPANY
Cincinnati
OH
|
Family ID: |
49325381 |
Appl. No.: |
13/838917 |
Filed: |
March 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13760527 |
Feb 6, 2013 |
|
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13838917 |
|
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61623054 |
Apr 11, 2012 |
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Current U.S.
Class: |
428/500 ;
522/182; 525/329.5; 526/317.1 |
Current CPC
Class: |
C08L 33/02 20130101;
Y10T 428/31855 20150401; C08F 220/06 20130101; A61L 15/60 20130101;
A61L 15/24 20130101; C08L 33/08 20130101; A61L 15/24 20130101; C08F
20/06 20130101; B01J 20/261 20130101 |
Class at
Publication: |
428/500 ;
526/317.1; 525/329.5; 522/182 |
International
Class: |
C08F 20/06 20060101
C08F020/06; B01J 20/26 20060101 B01J020/26 |
Claims
1. A superabsorbent polymer composition produced from an acrylic
composition, wherein said acrylic composition comprises an acrylic
acid composition, wherein said acrylic acid composition consists of
acrylic acid, acrylic acid derivatives, or mixtures thereof,
wherein said acrylic acid composition comprises at least about 98
wt % acrylic acid, acrylic acid derivatives, or mixtures thereof,
and wherein a portion of the remaining impurities in said acrylic
acid composition is hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof.
2. The composition of claim 1, wherein said hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof is lactic
acid, lactic acid derivatives, or mixtures thereof.
3. The superabsorbent polymer composition of claim 2 produced by
the steps comprising: a. Preparing a pre-polymerization solution
comprising: (i) said acrylic composition, and (ii) a solvent; and
wherein the pH of said pre-polymerization solution is less than
about 6; b. Combining an initiator with said pre-polymerization
solution to produce a polymerization mixture; c. Polymerizing said
polymerization mixture to produce a gel; and d. Drying said gel to
produce the superabsorbent polymer composition.
4. The composition of claim 3, wherein the amount of said acrylic
acid composition in said pre-polymerization solution is from about
5 wt % to about 95 wt %.
5. The composition of claim 3, wherein the amount of said initiator
is from about 0.01% wt % to about 10 wt %, based on the total
amount of said acrylic acid composition in said pre-polymerization
solution.
6. The composition of claim 3, wherein said pre-polymerization
solution further comprises a crosslinking agent in an amount of
less than about 10 wt %, based on the total amount of said acrylic
acid composition in said pre-polymerization solution.
7. The composition of claim 3, wherein said pre-polymerization
solution further comprises a dispersing aid.
8. The composition of claim 3, wherein said solvent is water.
9. The superabsorbent polymer composition of claim 2 produced by
the steps comprising: a. Preparing a pre-polymerization solution
comprising: (i) said acrylic composition, and (ii) a solvent; b.
Mixing a base into said pre-polymerization solution to form a
partially neutralized acrylic acid solution, and wherein the pH of
said partially neutralized acrylic acid solution is less than about
6; c. Combining an initiator with said partially neutralized
acrylic acid solution to produce a polymerization mixture; d.
Polymerizing said polymerization mixture to produce a gel; and e.
Drying said gel to produce said superabsorbent polymer
composition.
10. The composition of claim 9, wherein said partially neutralized
acrylic acid solution comprises at least about 20 mol % of an
acrylic acid salt, based on the total amount of said acrylic acid
composition, and wherein said acrylic acid salt is produced in said
mixing step.
11. The composition of claim 9, wherein said partially neutralized
acrylic acid solution comprises at least about 40 mol % of an
acrylic acid salt, based on the total amount of said acrylic acid
composition, and wherein said acrylic acid salt is produced in said
mixing step.
12. The composition of claim 9, wherein said partially neutralized
acrylic acid solution comprises at least about 60 mol % of an
acrylic acid salt, based on the total amount of said acrylic acid
composition, and wherein said acrylic acid salt is produced in said
mixing step.
13. The composition of claim 9, wherein said partially neutralized
acrylic acid solution comprises at least about 80 mol % of an
acrylic acid salt, based on the total amount of said acrylic acid
composition, and wherein said acrylic acid salt is produced in said
mixing step.
14. The composition of claim 9, wherein the amount of said acrylic
acid composition in said pre-polymerization solution is from about
5 wt % to about 95 wt %.
15. The composition of claim 9, wherein the amount of said
initiator is from about 0.01% wt % to about 10 wt %, based on the
total amount of said acrylic acid composition in said
pre-polymerization solution.
16. The composition of claim 9, wherein said pre-polymerization
solution further comprises a crosslinking agent in an amount of
less than about 10 wt %.
17. The composition of claim 9, wherein said pre-polymerization
solution further comprises a dispersing aid.
18. The composition of claim 9, wherein said solvent is water.
19. The superabsorbent polymer composition of claim 2 produced by
the steps comprising: a. Preparing a pre-polymerization solution
comprising: (i) said acrylic composition, and (ii) a solvent, and
wherein, the pH of said pre-polymerization solution is less than
about 6; b. Combining an initiator with said pre-polymerization
solution to produce a polymerization mixture; c. Polymerizing said
polymerization mixture to produce a gel; d. Adding a crosslinking
agent to said gel to produce a crosslinked surface polymer; and e.
Drying said crosslinked surface polymer to produce said
superabsorbent polymer composition.
20. The composition of claim 19, wherein the amount of said acrylic
acid composition in said pre-polymerization solution is from about
5 wt % to about 95 wt %.
21. The composition of claim 19, wherein the amount of said
initiator is from about 0.01% wt % to about 10 wt %, based on the
total amount of said acrylic acid composition in said
pre-polymerization solution.
22. The composition of claim 19, wherein said pre-polymerization
solution further comprises a crosslinking agent in an amount of
less than about 10 wt %.
23. The composition of claim 19, wherein said pre-polymerization
solution further comprises a dispersing aid.
24. The composition of claim 19, wherein said solvent is water.
25. The superabsorbent polymer composition of claim 2 produced by
the steps comprising: a. Preparing a pre-polymerization solution
comprising: (i) said acrylic composition, and (ii) a solvent; b.
Mixing a base into said pre-polymerization solution to form a
partially neutralized acrylic acid solution, and wherein the pH of
said partially neutralized acrylic acid solution is less than about
6; c. Combining an initiator with said partially neutralized
acrylic acid solution to produce a polymerization mixture; d.
Polymerizing said polymerization mixture to produce a gel; and e.
Adding a crosslinking agent to said gel to produce a crosslinked
surface polymer; and f. Drying said crosslinked surface polymer to
produce said superabsorbent polymer composition.
26. The composition of claim 25, wherein said partially neutralized
acrylic acid solution comprises at least about 20 mol % of an
acrylic acid salt, based on the total amount of said acrylic acid
composition, and wherein said acrylic acid salt is produced in said
mixing step.
27. The composition of claim 25, wherein said partially neutralized
acrylic acid solution comprises at least about 40 mol % of an
acrylic acid salt, based on the total amount of said acrylic acid
composition, and wherein said acrylic acid salt is produced in said
mixing step.
28. The composition of claim 25, wherein said partially neutralized
acrylic acid solution comprises at least about 60 mol % of an
acrylic acid salt, based on the total amount of said acrylic acid
composition, and wherein said acrylic acid salt is produced in said
mixing step.
29. The composition of claim 25, wherein said partially neutralized
acrylic acid solution comprises at least about 80 mol % of an
acrylic acid salt, based on the total amount of said acrylic acid
composition, and wherein said acrylic acid salt is produced in said
mixing step.
30. The composition of claim 25, wherein the amount of said acrylic
acid composition in said pre-polymerization solution is from about
5 wt % to about 95 wt %.
31. The composition of claim 25, wherein the amount of said
initiator is from about 0.01% wt % to about 10 wt %, based on the
total amount of said acrylic acid composition in said
pre-polymerization solution.
32. The composition of claim 25, wherein said pre-polymerization
solution further comprises a crosslinking agent in an amount of
less than about 10 wt %.
33. The composition of claim 25, wherein said pre-polymerization
solution further comprises a dispersing aid.
34. The composition of claim 25, wherein said solvent is water.
35. The superabsorbent polymer composition of claim 2 produced by
the steps comprising: a. Preparing a pre-polymerization solution
comprising glacial acrylic acid, methylene bis-acrylamide, and
water; b. Mixing sodium hydroxide into said pre-polymerization
solution to form a partially neutralized acrylic acid solution; c.
Combining 2,2'-azobis(2-methylpropionamidine)dihydrochloride with
said partially neutralized acrylic acid solution to produce a
polymerization mixture; d. Polymerizing said polymerization mixture
using UV light to produce a gel; and e. Drying said gel to produce
the superabsorbent polymer composition.
36. The superabsorbent polymer composition of claim 1 having a
bio-based content greater than about 3%.
37. The superabsorbent polymer composition of claim 1 having a
bio-based content greater than about 30%.
38. The superabsorbent polymer composition of claim 1 having a
bio-based content greater than about 90%.
39. The superabsorbent polymer composition of claim 1, wherein said
acrylic acid composition has a bio-based content greater than about
3%.
40. The superabsorbent polymer composition of claim 1, wherein said
acrylic acid composition has a bio-based content greater than about
30%.
41. The superabsorbent polymer composition of claim 1, wherein said
acrylic acid composition has a bio-based content greater than about
90%.
42. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has a cylinder retention capacity (CRC) between
about 20 g/g and about 45 g/g.
43. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has a cylinder retention capacity (CRC) between
about 25 g/g and about 40 g/g.
44. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has a cylinder retention capacity (CRC) between
about 30 g/g and about 35 g/g.
45. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has an extractables value from about 0 wt % to
about 20 wt %.
46. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has an extractables value from about 3 wt % to
about 15 wt %.
47. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has an extractables value from about 5 wt % to
about 10 wt %.
48. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has absorption against pressure (AAP) between
about 15 g/g and about 40 g/g.
49. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has absorption against pressure (AAP) between
about 20 g/g and about 35 g/g.
50. The superabsorbent polymer composition of claim 1, wherein said
polymer composition has absorption against pressure (AAP) between
about 25 g/g and about 30 g/g.
51. The superabsorbent polymer composition of claim 1, wherein the
amount of residual monomers in said polymer is about 500 ppm or
less.
52. An absorbent article selected from adult incontinence garments,
infant diapers, and feminine hygiene articles, comprising the
superabsorbent polymer composition of claim 1.
53. An absorbent article having opposing longitudinal edges, the
absorbent article comprising: a. a top sheet, b. a back sheet
joined with the top sheet; and c. an absorbent core disposed
between the top sheet and the back sheet, and wherein, the
absorbent core comprises a superabsorbent polymer composition
according to claim 1.
54. A poly(acrylic acid) composition produced from an acrylic
composition, wherein said acrylic composition comprises an acrylic
acid composition, wherein said acrylic acid composition consists of
acrylic acid, acrylic acid derivatives, or mixtures thereof,
wherein said acrylic acid composition comprises at least about 98
wt % acrylic acid, acrylic acid derivatives, or mixtures thereof,
and wherein a portion of the remaining impurities in said acrylic
acid composition is hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to the production of
poly(acrylic acid) (PAA) from bio-based acrylic acid, acrylic acid
derivatives, or mixtures thereof produced from hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof. More
specifically, the invention relates to the polymerization of
bio-based glacial acrylic acid, acrylic acid derivatives, or
mixtures thereof to form PAA or superabsorbent polymer (SAP).
BACKGROUND OF THE INVENTION
[0002] Acrylic acid or acrylate has a variety of industrial uses,
typically consumed in the form of polymers. In turn, these polymers
are commonly used in the manufacture of, among other things,
adhesives, binders, coatings, paints, polishes, detergents,
flocculants, dispersants, thixotropic agents, sequestrants, and
superabsorbent polymers, which are used in disposable absorbent
articles including diapers and hygienic products, for example.
Acrylic acid is commonly made from petroleum sources. For example,
acrylic acid has long been prepared by catalytic oxidation of
propylene. These and other methods of making acrylic acid from
petroleum sources are described in the Kirk-Othmer Encyclopedia of
Chemical Technology, Vol. 1, pgs. 342-369 (5.sup.th Ed., John Wiley
& Sons, Inc., 2004). Petroleum-based acrylic acid contributes
to greenhouse emissions due to its high petroleum derived carbon
content. Furthermore, petroleum is a non-renewable material, as it
takes hundreds of thousands of years to form naturally and only a
short time to consume. As petrochemical resources become
increasingly scarce, more expensive, and subject to regulations for
CO.sub.2 emissions, there exists a growing need for bio-based
acrylic acid or acrylate that can serve as an alternative to
petroleum-based acrylic acid or acrylate. Many attempts have been
made over the last 40 to 50 years to make bio-based acrylic acid or
acrylate from non-petroleum sources, such as lactic acid (also
known as 2-hydroxypropionic acid), 3-hydroxypropionic acid,
glycerin, carbon monoxide and ethylene oxide, carbon dioxide and
ethylene, and crotonic acid.
[0003] Petroleum-based superabsorbent polymer is made by
polymerization of petroleum-based acrylic acid using methods
described in Buchholz and Graham (eds), MODERN SUPERABSORENT
POLYMER TECHNOLOGY, J. Wiley & Sons, 1998, pages 69 to 117, or
recent patent applications, for example U.S. Patent Applications
2009/0275470 and 2011/0313113. The petroleum-based acrylic acid
used in these methods is glacial acrylic acid with purity exceeding
98% and typically being 99.5% or higher. The typical major
impurities in the petroleum-based glacial acrylic acid are
propionic acid, acetic acid, maleic anhydride, maleic acid,
acrolein, and furfural. On the other hand, the major impurities in
the bio-based glacial acrylic acid, acrylic acid derivatives, or
mixtures thereof produced from hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof, are
propionic acid, acetic acid, and hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof.
[0004] Accordingly, there is a need for commercially viable
processes of polymerizing bio-based glacial acrylic acid, acrylic
acid derivatives, or mixtures thereof produced from the dehydration
of hydroxypropionic acid, hydroxypropionic acid derivates, or
mixtures thereof, to PAA for detergents, flocculants, and other
applications; and SAP for use in diapers and other
applications.
SUMMARY OF THE INVENTION
[0005] In one embodiment of the present invention, a superabsorbent
polymer composition is provided produced from an acrylic
composition, wherein the acrylic composition comprises an acrylic
acid composition, wherein the acrylic acid composition consists of
acrylic acid, acrylic acid derivatives, or mixtures thereof,
wherein the acrylic acid composition comprises at least about 98 wt
% acrylic acid, acrylic acid derivatives, or mixtures thereof, and
wherein a portion of the remaining impurities in the acrylic acid
composition is hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof.
[0006] In another embodiment of the present invention, a
poly(acrylic acid) composition is provided produced from an acrylic
composition, wherein the acrylic composition comprises an acrylic
acid composition, wherein the acrylic acid composition consists of
acrylic acid, acrylic acid derivatives, or mixtures thereof,
wherein the acrylic acid composition comprises at least about 98 wt
% acrylic acid, acrylic acid derivatives, or mixtures thereof, and
wherein a portion of the remaining impurities in the acrylic acid
composition is hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof.
DETAILED DESCRIPTION OF THE INVENTION
I Definitions
[0007] As used herein, the term "poly(acrylic acid)" refers to
homopolymers of acrylic acid, or copolymers of acrylic acid and
other monomers.
[0008] As used herein, the term "superabsorbent polymer" refers to
a polymer which is capable of absorbing within the polymer at least
10 times its weight in deionized water, allowing for adjustment of
the pH of the system.
[0009] As used herein, the term "ion-exchange capacity" refers to
the theoretical or calculated ion-exchange capacity of the polymer
or polymers in milliequivalents per gram (meq/g) assuming that each
un-neutralized acid or base group becomes neutralized in the
ion-exchange process.
[0010] As used herein, the term "acrylic composition" refers to a
composition that includes an acrylic acid composition and other
materials, such as, water, other solvents, or mixtures thereof.
[0011] As used herein, the term "acrylic acid composition" refers
to a composition that consists of acrylic acid, acrylic acid
derivatives, or mixtures thereof.
[0012] As used herein, the term "distilled acrylic acid" refers to
a composition of acrylic acid with content of acrylic acid lower
than about 94 wt %.
[0013] As used herein, the term "crude acrylic acid" refers to a
composition of acrylic acid with content of acrylic acid between
about 94 wt % and about 98 wt %.
[0014] As used herein, the term "glacial acrylic acid" refers to a
composition of acrylic acid with content of acrylic acid at least
about 98 wt %.
[0015] As used herein, the term "bio-based" material refers to a
renewable material.
[0016] As used herein, the term "renewable material" refers to a
material that is produced from a renewable resource.
[0017] As used herein, the term "renewable resource" refers to a
resource that is produced via a natural process at a rate
comparable to its rate of consumption (e.g., within a 100 year time
frame). The resource can be replenished naturally, or via
agricultural techniques. Non-limiting examples of renewable
resources include plants (e.g., sugar cane, beets, corn, potatoes,
citrus fruit, woody plants, lignocellulose, hemicellulose,
cellulosic waste), animals, fish, bacteria, fungi, and forestry
products. These resources can be naturally occurring, hybrids, or
genetically engineered organisms. Natural resources, such as crude
oil, coal, natural gas, and peat, which take longer than 100 years
to form, are not considered renewable resources. Because at least
part of the material of the invention is derived from a renewable
resource, which can sequester carbon dioxide, use of the material
can reduce global warming potential and fossil fuel
consumption.
[0018] As used herein, the term "bio-based content" refers to the
amount of carbon from a renewable resource in a material as a
percent of the weight (mass) of the total organic carbon in the
material, as determined by ASTM D6866-10 Method B.
[0019] As used herein, the term "petroleum-based" material refers
to a material that is produced from fossil material, such as
petroleum, natural gas, coal, etc.
[0020] As used herein, the term "condensed phosphate" refers to any
salts containing one or several P--O--P bonds generated by corner
sharing of PO.sub.4 tetrahedra.
[0021] As used herein, the term "cyclophosphate" refers to any
cyclic condensed phosphate constituted of two or more
corner-sharing PO.sub.4 tetrahedra.
[0022] As used herein, the term "monophosphate" or "orthophosphate"
refers to any salt whose anionic entity, [PO.sub.4]3.sup.-, is
composed of four oxygen atoms arranged in an almost regular
tetrahedral array about a central phosphorus atom.
[0023] As used herein, the term "oligophosphate" refers to any
polyphosphates that contain five or less PO.sub.4 units.
[0024] As used herein, the term "polyphosphate" refers to any
condensed phosphates containing linear P--O--P linkages by corner
sharing of PO.sub.4 tetrahedra leading to the formation of finite
chains.
[0025] As used herein, the term "ultraphosphate" refers to any
condensed phosphate where at least two PO.sub.4 tetrahedra of the
anionic entity share three of their corners with the adjacent
ones.
[0026] As used herein, the term "cation" refers to any atom or
group of covalently-bonded atoms having a positive charge.
[0027] As used herein, the term "monovalent cation" refers to any
cation with a positive charge of +1.
[0028] As used herein, the term "polyvalent cation" refers to any
cation with a positive charge equal or greater than +2.
[0029] As used herein, the term "anion" refers to any atom or group
of covalently-bonded atoms having a negative charge.
[0030] As used herein, the term "heteropolyanion" refers to any
anion with covalently bonded XO.sub.p and YO.sub.r polyhedra, and
thus includes X--O--Y and possibly X--O--X and Y--O--Y bonds,
wherein X and Y represent any atoms, and wherein p and r are any
positive integers.
[0031] As used herein, the term "heteropolyphosphate" refers to any
heteropolyanion, wherein X represents phosphorus (P) and Y
represents any other atom.
[0032] As used herein, the term "phosphate adduct" refers to any
compound with one or more phosphate anions and one or more
non-phosphate anions that are not covalently linked.
[0033] As used herein, the terms "LA" refers to lactic acid, "AA"
refers to acrylic acid, "AcH" refers to acetaldehyde, and "PA"
refers to propionic acid.
[0034] As used herein, the term "particle span" refers to a
statistical representation of a given particle sample and is equal
to (D.sub.v,0.90-D.sub.v,0.10)/D.sub.v,0.50. The term "median
particle size" or D.sub.v,0.50 refers to the diameter of a particle
below which 50% of the total volume of particles lies. Further,
D.sub.v,0.10 refers to the particle size that separates the
particle sample at the 10% by volume fraction and D.sub.v,0.90, is
the particle size that separates the particle sample at the 90% by
volume fraction.
[0035] As used herein, the term "conversion" in % is defined as
[hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof flow rate in (mol/min)-hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof flow rate
out (mol/min)]/[hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof flow rate in (mol/min)]*100. For
the purposes of this invention, the term "conversion" means molar
conversion, unless otherwise noted.
[0036] As used herein, the term "yield" in % is defined as [product
flow rate out (mol/min)/hydroxypropionic acid, hydroxypropionic
acid derivatives, or mixtures thereof flow rate in (mol/min)]*100.
For the purposes of this invention, the term "yield" means molar
yield, unless otherwise noted.
[0037] As used herein, the term "selectivity" in % is defined as
[Yield/Conversion]*100. For the purposes of this invention, the
term "selectivity" means molar selectivity, unless otherwise
noted.
[0038] As used herein, the term "total flow rate out" in mol/min
and for hydroxypropionic acid is defined as: (2/3)*[C2 flow rate
out (mol/min)]+[C3 flow rate out (mol/min)]+(2/3)*[acetaldehyde
flow rate out (mol/min)]+(4/3)*[C4 flow rate out
(mol/min)]+[hydroxypropionic acid flow rate out (mol/min)]+[pyruvic
acid flow rate out (mol/min)]+(2/3)*[acetic acid flow rate out
(mol/min)]+[1,2-propanediol flow rate out (mol/min)]+[propionic
acid flow rate out (mol/min)]+[acrylic acid flow rate out
(mol/min)]+(5/3)*[2,3-pentanedione flow rate out
(mol/min)]+(1/3)*[carbon monoxide flow rate out
(mol/min)]+(1/3)*[carbon dioxide flow rate out (mol/min)]. If a
hydroxypropionic acid derivative is used instead of
hydroxypropionic acid, the above formula needs to be adjusted
according to the number of carbon atoms in the hydroxypropionic
acid derivative.
[0039] As used herein, the term "C2" means ethane and ethylene.
[0040] As used herein, the term "C3" means propane and
propylene.
[0041] As used herein, the term "C4" means butane and butenes.
[0042] As used herein, the term "total molar balance" or "TMB" in %
is defined as [total flow rate out (mol/min)/hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof flow rate in
(mol/min)]*100.
[0043] As used herein, the term "the acrylic acid yield was
corrected for TMB" is defined as [acrylic acid yield/total molar
balance]*100, to account for slightly higher flows in the
reactor.
[0044] As used herein, the term "Gas Hourly Space Velocity" or
"GHSV" in h.sup.-1 is defined as 60.times.[Total gas flow rate
(mL/min)/catalyst bed volume (mL)]. The total gas flow rate is
calculated under Standard Temperature and Pressure conditions (STP;
0.degree. C. and 1 atm).
[0045] As used herein, the term "Liquid Hourly Space Velocity" or
"LHSV" in h.sup.-1 is defined as 60.times.[Total liquid flow rate
(mL/min)/catalyst bed volume (mL)].
II Poly(Acrylic Acid) and its Preparation Methods
[0046] Unexpectedly it has been found that bio-based glacial
acrylic acid, acrylic acid derivatives, or mixtures thereof can be
polymerized to produce poly(acrylic acid) or superabsorbent polymer
using processes that are similar to those used in producing
poly(acrylic acid) or superabsorbent polymer from petroleum-derived
glacial acrylic acid, acrylic acid derivatives, or mixtures
thereof. Although the impurities that are present in bio-based
acrylic acid, acrylic acid derivatives, or mixtures thereof are
different than those present in the petroleum-based glacial acrylic
acid, acrylic acid derivatives, or mixtures thereof, the same
processes that are used to polymerize the petroleum-based glacial
acrylic acid, acrylic acid derivatives, or mixtures thereof (e.g.
processes for superabsorbent polymer disclosed in U.S. Pat. No.
7,307,132 (issued in 2007) and U.S. Patent Applications
2009/0275470, 2011/0306732, 2011/0313113, and 2012/0091392; all
incorporated herein by reference) can be used to polymerize
bio-based glacial acrylic acid, acrylic acid derivatives, or
mixtures thereof.
[0047] In one embodiment, a superabsorbent polymer composition is
provided and is produced from an acrylic composition, wherein the
acrylic composition comprises an acrylic acid composition, wherein
the acrylic acid composition consists of acrylic acid, acrylic acid
derivatives, or mixtures thereof, wherein the acrylic acid
composition comprises at least about 98 wt % acrylic acid, acrylic
acid derivatives, or mixtures thereof, and wherein a portion of the
remaining impurities in the acrylic acid composition is
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof.
[0048] The acrylic composition comprises the acrylic acid
composition and optionally other materials, such as, by way of
example and not limitation, water, other solvents, or mixtures
thereof.
[0049] Hydroxypropionic acid can be 3-hydroxypropionic acid,
2-hydroxypropionic acid (also called, lactic acid), 2-methyl
hydroxypropionic acid, or mixtures thereof. Derivatives of
hydroxypropionic acid can be metal or ammonium salts of
hydroxypropionic acid, alkyl esters of hydroxypropionic acid, alkyl
esters of 2-methyl hydroxypropionic acid, cyclic di-esters of
hydroxypropionic acid, hydroxypropionic acid anhydride, or a
mixture thereof. Non-limiting examples of metal salts of
hydroxypropionic acid are sodium hydroxypropionate, potassium
hydroxypropionate, and calcium hydroxypropionate. Non-limiting
examples of alkyl esters of hydroxypropionic acid are methyl
hydroxypropionate, ethyl hydroxypropionate, butyl
hydroxypropionate, 2-ethylhexyl hydroxypropionate, or mixtures
thereof. A non-limiting example of cyclic di-esters of
hydroxypropionic acid is dilactide.
[0050] In one embodiment, the hydroxypropionic acid is lactic acid
or 2-methyl lactic acid. In another embodiment, the
hydroxypropionic acid is lactic acid. Lactic acid can be L-lactic
acid, D-lactic acid, or mixtures thereof. In one embodiment, the
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof in the impurities in the glacial acrylic acid
composition are lactic acid, lactic acid derivatives, or mixtures
thereof.
[0051] The acrylic acid derivatives can be acrylic acid oligomers,
metal or ammonium salts of monomeric acrylic acid, metal or
ammonium salts of acrylic acid oligomers, or mixtures thereof.
Non-limiting examples of metal salts of acrylic acid are sodium
acrylate and potassium acrylate. Non-limiting examples of alkyl
esters of acrylic acid are methyl lactate, ethyl lactate, or
mixtures thereof.
[0052] The acrylic acid, acrylic acid derivatives, or mixtures
thereof can be made from renewable resources or materials.
Non-limiting examples of renewable resources or materials are
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof; glycerin; carbon monoxide and ethylene oxide;
carbon dioxide and ethylene; and crotonic acid. In one embodiment,
the renewable resources or materials are hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof. In another
embodiment, the renewable resources or materials are lactic acid,
lactic acid derivatives, or mixtures thereof. In yet another
embodiment, the renewable resource or material is lactic acid.
[0053] In one embodiment, the superabsorbent polymer composition is
produced by the steps comprising: a) preparing a pre-polymerization
solution containing: (i) the acrylic composition, and (ii) a
solvent; and wherein, the pH of the pre-polymerization solution is
less than about 6; b) combining an initiator with the
pre-polymerization solution to produce a polymerization mixture; c)
polymerizing the polymerization mixture to produce a gel; and d)
drying the gel to produce the superabsorbent polymer
composition.
[0054] In another embodiment, the superabsorbent polymer
composition is produced by the steps comprising: a) preparing a
pre-polymerization solution comprising: (i) the acrylic
composition, and (ii) a solvent; b) mixing a base into the
pre-polymerization solution to form a partially neutralized acrylic
acid solution, and wherein, the pH of the partially neutralized
acrylic acid solution is less than about 6; c) combining an
initiator with the partially neutralized acrylic acid solution to
produce a polymerization mixture; d) polymerizing the
polymerization mixture to produce a gel; and e) drying the gel to
produce the superabsorbent polymer composition.
[0055] In one embodiment, the superabsorbent polymer composition is
produced by the steps comprising: a) preparing a pre-polymerization
solution containing: (i) the acrylic composition, and (ii) a
solvent; and wherein, the pH of the pre-polymerization solution is
less than about 6; b) combining an initiator with the
pre-polymerization solution to produce a polymerization mixture; c)
polymerizing the polymerization mixture to produce a gel; d) adding
a crosslinking agent to the gel to produce a crosslinked surface
polymer; and e) drying the crosslinked surface polymer to produce
the superabsorbent polymer composition.
[0056] In another embodiment, the superabsorbent polymer
composition is produced by the steps comprising: a) preparing a
pre-polymerization solution comprising: (i) the acrylic
composition, and (ii) a solvent; b) mixing a base into the
pre-polymerization solution to form a partially neutralized acrylic
acid solution, and wherein, the pH of the partially neutralized
acrylic acid solution is less than about 6; c) combining an
initiator with the partially neutralized acrylic acid solution to
produce a polymerization mixture; d) polymerizing the
polymerization mixture to produce a gel; e) adding a crosslinking
agent to the gel to produce a crosslinked surface polymer; and f)
drying the crosslinked surface polymer to produce the
superabsorbent polymer composition.
[0057] In another embodiment, the superabsorbent polymer
composition is produced by the steps comprising: a) preparing a
pre-polymerization solution comprising: glacial acrylic acid,
methylene bis-acrylamide, and water; b) mixing sodium hydroxide
into the pre-polymerization solution to form a partially
neutralized acrylic acid solution; c) combining
2,2'-azobis(2-methylpropionamidine)dihydrochloride with the
partially neutralized acrylic acid solution to produce a
polymerization mixture; d) polymerizing the polymerization mixture
using UV light to produce a gel; and e) drying the gel to produce
the superabsorbent polymer composition.
[0058] In one embodiment, the solvent of the pre-polymerization
solution is selected from the group comprising water, organic
solvents, and mixtures thereof. In yet another embodiment, the
solvent of the pre-polymerization solution is water. In another
embodiment, the pH of the pre-polymerization solution is between
about 3 and about 5. In another embodiment, the pH of the partially
neutralized acrylic acid solution is between about 3 and about
5.
[0059] In another embodiment, the amount of the acrylic acid
composition in the pre-polymerization solution is from about 5 wt %
to about 95 wt %. In another embodiment, the amount of water in the
pre-polymerization solution is from about 5 wt % to about 95 wt %.
In yet another embodiment, the pre-polymerization solution further
comprises a dispersing aid. In one embodiment, the dispersing aid
is carboxymethyl cellulose (CMC).
[0060] In another embodiment, the pre-polymerization solution
further comprises a crosslinking agent. In yet another embodiment,
the crosslinking agent is present in an amount of less than about
10 wt %, based on the total amount of said acrylic acid composition
in said pre-polymerization solution. In one embodiment, the
crosslinking agent is selected from the group consisting of di- or
poly-functional monomers, having two or more groups that can be
polymerized, such as N,N-methylenebisacrylamide, trimethylolpropane
triacrylate, ethylene glycol di(meth)acrylate, or triallylamine,
and other organic crosslinking agents that may be apparent to those
having ordinary skills in the art.
[0061] In one embodiment, the initiator is an amount from about
0.01% wt % to about 10 wt %, based on the total amount of the
acrylic acid composition in the pre-polymerization solution. In
another embodiment, the initiator can be added as a solid or in
combination with an initiator solvent, wherein the initiator and
initiator solvent are forming a liquid solution or dispersion. A
non-limiting example of the initiator solvent is water.
Non-limiting examples of initiators are chemical compounds selected
from the group comprising hydroperoxides, hydrogen peroxide,
organic peroxides, azo compounds, persulfates, other redox
initiators, and mixtures thereof. Non-limiting examples of
hydroperoxides are tert-butyl hydroperoxide and cumene
hydroperoxide. Non-limiting examples of organic peroxides are
acetylacetone peroxide, methyl ethyl ketone peroxide, tert-amyl
perpivalate, tert-butyl perpivalate, tert-butyl perneohexanoate,
tert-butyl perisobutyrate, tert-butyl per-2-ethylhexanoate,
tert-butyl perisononanoate, tert-butyl permaleate, tert-butyl
perbenzoate, di(2-ethylhexyl)peroxydicarbonate, dicyclohexyl
peroxydicarbonate, di(4-tert-butylcyclohexyl)peroxydicarbonate,
dimyristyl peroxydicarbonate, diacetyl peroxydicarbonate, allyl
peresters, cumyl peroxyneodecanoate, tert-butyl
per-3,5,5-tri-methylhexanoate, acetylcyclohexylsulfonyl peroxide,
dilauryl peroxide, dibenzoyl peroxide, and tert-amyl
perneodecanoate. Non-limiting examples of azo compounds are
2,2'-azobisisobutyronitrile,
2,2'-azobis(2,4-dimethylvaleronitrile),
2,2'-azobis(4-methoxy-2,4-dimethyl-valeronitrile),
2,2'-azobis-{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochlor-
ide, 2,2'-azobis-(2-amidinopropane)dihydrochloride,
2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, and
2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride.
Non-limiting examples of persulfates are sodium peroxodisulfate,
potassium peroxodisulfate and ammonium peroxodisulfate. In another
embodiment, a mixture of two or more initiators is used.
[0062] In another embodiment, a polymerization catalyst can be
used. A non-limiting example of a polymerization catalyst is TMEDA
(N,N,N',N'-tetramethylethylenediamine). Polymerization methods to
prepare the superabsorbent polymer composition can include free
radical, ring-opening, condensation, anionic, cationic, or
irradiation techniques. The polymerization rate can be controlled
through the identity and amount of initiators and the
polymerization temperature. The polymerization of the acrylic acid
composition can be highly exothermic, and hence, in one embodiment,
the polymerization solution can be cooled during
polymerization.
[0063] In one embodiment, the partially neutralized acrylic acid
solution comprises at least about 20 mol % of an acrylic acid salt,
based on the total amount of the acrylic acid composition, and
wherein the acrylic acid salt is produced in the mixing step. In
another embodiment, the partially neutralized acrylic acid solution
comprises at least about 40 mol % of an acrylic acid salt, based on
the total amount of the acrylic acid composition, and wherein the
acrylic acid salt is produced in the mixing step. In another
embodiment, the partially neutralized acrylic acid solution
comprises at least about 60 mol % of an acrylic acid salt, based on
the total amount of the acrylic acid composition, and wherein the
acrylic acid salt is produced in the mixing step. In another
embodiment, the partially neutralized acrylic acid solution
comprises at least about 80 mol % of an acrylic acid salt, based on
the total amount of the acrylic acid composition, and wherein the
acrylic acid salt is produced in the mixing step.
[0064] In one embodiment, at least about 20 mol % of the acrylic
acid composition in the partially neutralized acrylic acid solution
contains a carboxylate group with a cationic counter ion. In
another embodiment, at least about 40 mol % of the acrylic acid
composition in the partially neutralized acrylic acid solution
contains a carboxylate group with a cationic counter ion. In
another embodiment, at least about 60 mol % of the acrylic acid
composition in the partially neutralized acrylic acid solution
contains a carboxylate group with a cationic counter ion. In
another embodiment, at least about 80 mol % of the acrylic acid
composition in the partially neutralized acrylic acid solution
contains a carboxylate group with a cationic counter ion.
Non-limiting examples of bases are sodium hydroxide and potassium
hydroxide.
[0065] In another embodiment, a crosslinking agent is added to the
gel after the polymerization is completed to produce a crosslinked
surface polymer, and the crosslinked surface polymer is dried to
produce the superabsorbent polymer composition. Surface
crosslinking of the initially formed polymers is a preferred
process for obtaining superabsorbent polymers having relatively
high performance under pressure (PUP) capacity, porosity and
permeability. Non-limiting examples of processes to produce a
crosslinked surface polymer are: those where a) a di- or
poly-functional reagent (s) capable of reacting with existing
functional groups within the superabsorbent polymer is applied to
the surface of the polymer; b) a di- or poly-functional reagent
that is capable of reacting with other added reagents and possibly
existing functional groups within the absorbent polymer such as to
increase the level of crosslinking at the surface is applied to the
surface; c) additional reaction (s) is induced amongst existing
components within the superabsorbent polymer, such as to generate a
higher level of crosslinking at or near the surface; among others
that may be apparent to those having skill in the art.
[0066] In one embodiment, the superabsorbent polymer composition
comprises: a) a cation-exchange absorbent polymer prepared from an
acrylic composition, wherein the acrylic composition comprises an
acrylic acid composition, wherein the acrylic acid composition
consists of acrylic acid, acrylic acid derivatives, or mixtures
thereof, wherein the acrylic acid composition comprises at least
about 98 wt % acrylic acid, acrylic acid derivatives, or mixtures
thereof, and wherein a portion of the remaining impurities in the
acrylic acid composition is hydroxypropionic acid, hydroxypropionic
acid derivatives, or mixtures thereof; and b) an anion-exchange
absorbent polymer, wherein the ion-exchange capacity of the
anion-exchange absorbent polymer is at least about 15 meq/g.
[0067] In one embodiment, the hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof in the
impurities in the glacial acrylic acid composition are lactic acid,
lactic acid derivatives, or mixtures thereof.
[0068] In another embodiment, the cation-exchange absorbent polymer
is from about 80% to about 100% in the un-neutralized acid form and
the anion-exchange absorbent polymer is from about 80% to about
100% in the un-neutralized base form. In another embodiment, the
anion-exchange absorbent polymer is prepared from a monomer
selected from the group consisting of ethylenimine, allylamine,
diallylamine, 4-aminobutene, alkyl oxazolines, vinylformamide,
5-aminopentene, carbodiimides, formaldazine, and melamine; a
secondary amine derivative of any of the foregoing; a tertiary
amine derivative of any of the foregoing; and mixtures therefore.
In another embodiment, the anion-exchange absorbent polymer is
prepared from a monomer selected from the group consisting of
ethylenimine, allylamine, diallylamine, and mixtures thereof.
[0069] In another embodiment, the superabsorbent polymer
composition comprises: a) the anion-exchange absorbent polymer
selected from the group consisting of poly(ethylenimine);
poly(allylamine); and mixtures thereof; and b) the cation-exchange
polymer is a homopolymer or copolymer of the acrylic acid prepared
from an acrylic composition, wherein the acrylic composition
comprises an acrylic acid composition, wherein the acrylic acid
composition consists of acrylic acid, acrylic acid derivatives, or
mixtures thereof, wherein the acrylic acid composition comprises at
least about 98 wt % acrylic acid, acrylic acid derivatives, or
mixtures thereof, and wherein a portion of the remaining impurities
in the acrylic acid composition is hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof. In another
embodiment, the cation-exchange absorbent polymer is homogenously
crosslinked.
[0070] In one embodiment, the bio-based content of the acrylic acid
composition is greater than about 3%. In another embodiment, the
bio-based content of the acrylic acid composition is greater than
30%. In yet another embodiment, the bio-based content of the
acrylic acid composition is greater than about 90%. In one
embodiment, the bio-based content of the superabsorbent polymer
composition is greater than about 3%. In another embodiment, the
bio-based content of the superabsorbent polymer composition is
greater than 30%. In yet another embodiment, the bio-based content
of the superabsorbent polymer composition is greater than about
90%.
[0071] In one embodiment, the superabsorbent polymer composition
has a cylinder retention capacity (CRC) between about 20 g/g and
about 45 g/g. In another embodiment, the superabsorbent polymer
composition has a cylinder retention capacity (CRC) between about
25 g/g and about 40 g/g. In yet another embodiment, the
superabsorbent polymer composition has a cylinder retention
capacity (CRC) between about 30 g/g and about 35 g/g.
[0072] In one embodiment, the superabsorbent polymer composition
has an extractables value from about 0 wt % to about 20 wt %. In
another embodiment, the superabsorbent polymer composition has an
extractables value from about 3 wt % to about 15 wt %. In yet
another embodiment, the superabsorbent polymer composition has an
extractables value from about 5 wt % to about 10 wt %.
[0073] In one embodiment, the superabsorbent polymer composition
has absorption against pressure (AAP) between about 15 g/g and
about 40 g/g. In another embodiment, the superabsorbent polymer
composition has absorption against pressure (AAP) between about 20
g/g and about 35 g/g. In yet another embodiment, the superabsorbent
polymer composition has absorption against pressure (AAP) between
about 25 g/g and about 30 g/g.
[0074] In one embodiment, the amount of residual monomers in the
superabsorbent polymer composition is about 500 ppm or less.
[0075] In one embodiment, an absorbent article is provided and is
selected from adult incontinence garments, infant diapers, and
feminine hygiene articles, and produced from an acrylic
composition, wherein the acrylic composition comprises an acrylic
acid composition, wherein the acrylic acid composition consists of
acrylic acid, acrylic acid derivatives, or mixtures thereof,
wherein the acrylic acid composition comprises at least about 98 wt
% acrylic acid, acrylic acid derivatives, or mixtures thereof, and
wherein a portion of the remaining impurities in the acrylic acid
composition is hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof.
[0076] In another embodiment, an absorbent article is provided
having opposing longitudinal edges and comprising: a) a top sheet;
b) a back sheet joined with the top sheet; and c) an absorbent core
disposed between the top sheet and the back sheet, and wherein, the
absorbent core comprises a superabsorbent polymer composition
produced from an acrylic composition, wherein the acrylic
composition comprises an acrylic acid composition, wherein the
acrylic acid composition consists of acrylic acid, acrylic acid
derivatives, or mixtures thereof, wherein the acrylic acid
composition comprises at least about 98 wt % acrylic acid, acrylic
acid derivatives, or mixtures thereof, and wherein a portion of the
remaining impurities in the acrylic acid composition is
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof.
[0077] In one embodiment, an absorbent member comprises an
agglomerate of: a) particulate superabsorbent polymer composition
prepared from an acrylic composition, wherein the acrylic
composition comprises an acrylic acid composition, wherein the
acrylic acid composition consists of acrylic acid, acrylic acid
derivatives, or mixtures thereof, wherein the acrylic acid
composition comprises at least about 98 wt % acrylic acid, acrylic
acid derivatives, or mixtures thereof, and wherein a portion of the
remaining impurities in the acrylic acid composition is
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof; and b) particulate high surface area open-celled
hydrophilic foam, wherein the foam, in combination with the
superabsorbent polymer composition, provides the absorbent member
with high capillary sorption absorbent capacity. The absorbent
member is useful in the containment (e.g. storage) of body liquid
fluids such as urine. As used herein, the term "agglomerate" refers
to a unitary combination of particulate materials that is not
easily separable, i.e. the agglomerate does not substantially
separate into its component particles as a result of normal
manufacturing, normal shipping, and/or normal use. High surface
area foams useful herein are those that are relatively open-celled,
i.e. many of the individual cells of the foam are in unobstructed
communication with adjoining cells, allowing liquid transfer from
one cell to the other within the foam structure. In addition to
being open-celled, these high surface area foams are sufficiently
hydrophilic to permit the foam to absorb aqueous liquids.
[0078] In another embodiment, the high surface area open-celled
hydrophilic foam is obtained by polymerizing a high internal phase
water-in-oil emulsion (HIPE). In another embodiment, a hydratable,
and preferably hygroscopic or deliquescent, water soluble inorganic
salt is incorporated into the HIPE. Non-limiting examples of water
soluble inorganic salts are alkaline earth metal salts, such as
calcium chloride. In one embodiment, the agglomerate comprises from
about 1 wt % to about 98 wt % high surface area open-celled
hydrophilic foam, based on the total weight of the agglomerate. In
another embodiment, the agglomerate comprises from about 15 wt % to
about 85 wt % high surface area open-celled hydrophilic foam, based
on the total weight of the agglomerate. In yet another embodiment,
the agglomerate comprises from about 30 wt % to about 40 wt % high
surface area open-celled hydrophilic foam, based on the total
weight of the agglomerate.
[0079] In another embodiment, a poly(acrylic acid) composition is
provided and is produced from an acrylic composition, wherein the
acrylic composition comprises an acrylic acid composition, wherein
the acrylic acid composition consists of acrylic acid, acrylic acid
derivatives, or mixtures thereof, wherein the acrylic acid
composition comprises at least about 98 wt % acrylic acid, acrylic
acid derivatives, or mixtures thereof, and wherein a portion of the
remaining impurities in the acrylic acid composition is
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof.
III Catalysts for the Conversion of Hydroxypropionic Acid or its
Derivatives to Acrylic Acid or its Derivatives
[0080] In one embodiment, the catalyst includes: (a) monohydrogen
monophosphate and dihydrogen monophosphate anions described by
formulae (I) and (II):
[HPO.sub.4].sup.2- (I),
[H.sub.2PO.sub.4].sup.- (II),
and (b) at least two different cations, wherein the catalyst is
essentially neutrally charged; and further, wherein the molar ratio
of said monohydrogen monophosphate anion to said dihydrogen
monophosphate anion in the catalyst is between about 0.1 and about
10. In another embodiment, the molar ratio of monohydrogen
monophosphate anion to dihydrogen monophosphate anion is between
about 0.2 and about 5. In yet another embodiment, the molar ratio
of monohydrogen monophosphate anion to dihydrogen monophosphate
anion is about 1.
[0081] In one embodiment of the present invention, the catalyst
includes the monophosphate salts described by the formulae (III)
and (IV):
M.sup.IIHPO.sub.4 (III),
M.sup.IH.sub.2PO.sub.4 (IV), and
wherein M.sup.I is a monovalent cation and M.sup.II is a divalent
cation. In another embodiment, the molar ratio of M.sup.IIHPO.sub.4
to M.sup.IH.sub.2PO.sub.4 is between about 0.1 and about 10. In
another embodiment, the molar ratio of M.sup.IIHPO.sub.4 to
M.sup.IH.sub.2PO.sub.4 is between about 0.2 and about 5. In yet
another embodiment, the molar ratio of M.sup.IIHPO.sub.4 to
M.sup.IH.sub.2PO.sub.4 is about 1.
[0082] In one embodiment of the present invention, the catalyst
includes a monophosphate salt described by the formula (V):
M.sup.II.sub.2-.alpha.M.sup.I.sub..alpha.H.sub..alpha.(HPO.sub.4).sub.2
(V),
wherein M.sup.I is a monovalent cation and M.sup.II is a divalent
cation; and wherein a is greater than about 0.2 and smaller than
about 1.8. In another embodiment of the present invention, a is
about 1.
[0083] In another embodiment, the monohydrogen monophosphate anion
described by formula (I) is substituted by one or more phosphate
anions described by the formula
[H.sub.(1-.beta.)P.sub.(1+.beta.)O.sub.(4+3.beta.)].sup.2(1+.beta.)-,
wherein .beta. is greater or equal to zero and less or equal to
1.
[0084] In another embodiment, the dihydrogen monophosphate anion
described by formula (II) is substituted by one or more phosphate
anions described by the formula
[H.sub.2(1-.beta.)PO.sub.(4-.beta.)].sup.-, wherein .beta. is
greater or equal to zero and less or equal to 1.
[0085] In one embodiment, the catalyst comprises: (a) at least one
condensed phosphate anion selected from the group consisting of
formulae (VI), (VII), and (VIII),
[P.sub.nO.sub.3n+1].sup.(n+2)- (VI)
[P.sub.nO.sub.3n].sup.n- (VII)
[P.sub.(2m+n)O.sub.(5m+3n)].sup.n- (VIII)
wherein n is at least 2 and m is at least 1, and (b) at least two
different cations, wherein the catalyst is essentially neutrally
charged, and further, wherein the molar ratio of phosphorus to the
at least two different cations is between about 0.7 and about
1.7.
[0086] The anions defined by formulae (VI), (VII), and (VIII) are
also referred to as polyphosphates (or oligophosphates),
cyclophosphates, and ultraphosphates, respectively.
[0087] In another embodiment, the catalyst comprises: (a) at least
one condensed phosphate anion selected from the group consisting of
formulae (VI) and (VII),
[P.sub.nO.sub.3n+1].sup.(n+2)- (VI)
[P.sub.nO.sub.3n].sup.n- (VII)
wherein n is at least 2, and (b) at least two different cations,
wherein the catalyst is essentially neutrally charged, and further,
wherein the molar ratio of phosphorus to the at least two different
cations is between about 0.7 and about 1.7.
[0088] In one embodiment, the molar ratio of phosphorus to the
cations in the catalyst is between about 0.7 and about 1.7; in
another embodiment, the molar ratio of phosphorus to the cations in
the catalyst is between about 0.8 and about 1.3; and in yet another
embodiment, the molar ratio of phosphorus to the cations in the
catalyst is about 1.
[0089] In one embodiment, the at least two different cations
comprise (a) at least one monovalent cation, and (b) at least one
polyvalent cation. In another embodiment, the molar ratio of the
monovalent cations to the polyvalent cations is between about 0.1
and about 10. In yet another embodiment, the molar ratio of the
monovalent cations to the polyvalent cations is between about 0.5
and about 5. In a further embodiment of the present invention, the
molar ratio of the monovalent cations to the polyvalent cations is
about 1.
[0090] In another embodiment, the polyvalent cation is selected
from the group consisting of divalent cations, trivalent cations,
tetravalent cations, pentavalent cations, and mixtures thereof.
Non-limiting examples of monovalent cations are H.sup.+, Li.sup.+,
Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, Ag.sup.+, Rb.sup.+,
Tl.sup.+, and mixtures thereof. In one embodiment, the monovalent
cation is selected from the group consisting of Li.sup.+, Na.sup.+,
K.sup.+, Rb.sup.+, Cs.sup.+, and mixtures thereof; in another
embodiment, the monovalent cation is Na.sup.+ or K.sup.+; and in
yet another embodiment, the monovalent cation is K.sup.+.
Non-limiting examples of polyvalent cations are cations of the
alkaline earth metals (i.e., Be, Mg, Ca, Sr, Ba, and Ra),
transition metals (e.g. Y, Ti, Zr, V, Nb, Cr, Mo, Mn, Re, Fe, Ru,
Co, Rh, Ni, Pd, Pt, Cu, Ag, and Au), poor metals (e.g. Zn, Ga, Si,
Ge, B, Al, In, Sb, Sn, Bi, and Pb), lanthanides (e.g. La and Ce),
and actinides (e.g. Ac and Th). In one embodiment, the polyvalent
cation is selected from the group consisting of Be.sup.2+,
Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+, Mn.sup.2+, Fe.sup.2+,
Co.sup.2+, Ni.sup.2+, Cu.sup.2+, Zn.sup.2+, Cd.sup.2+, Sn.sup.2+,
Pb.sup.2+, Ti.sup.3+, Cr.sup.3+, Mn.sup.3+, Fe.sup.3+, Al.sup.3+,
Ga.sup.3+, Y.sup.3+, In.sup.3+, Sb.sup.3+, Bi.sup.3+, Si.sup.4+,
Ti.sup.4+, V.sup.4+, Ge.sup.4+, Mo.sup.4+, Pt.sup.4+, V.sup.5+,
Nb.sup.5+, Sb.sup.5+, and mixtures thereof. In one embodiment, the
polyvalent cation is selected from the group consisting of
Ca.sup.2+, Ba.sup.2+, Cu.sup.2+, Mn.sup.2+, Mn.sup.3+, and mixtures
thereof; in another embodiment, the polyvalent cation is selected
from the group consisting of Ca.sup.2+, Ba.sup.2+, Mn.sup.3+, and
mixtures thereof; and in yet another embodiment, the polyvalent
cation is Ba.sup.2+.
[0091] The catalyst can include cations: (a) H.sup.+, Li.sup.+,
Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, or mixtures thereof; and (b)
Be.sup.2+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+, Mn.sup.2+,
Fe.sup.2+, Co.sup.2+, Ni.sup.2+, Cu.sup.2+, Zn.sup.2+, Cd.sup.2+,
Sn.sup.2+, Pb.sup.2+, Ti.sup.3+, Cr.sup.3+, Mn.sup.3+, Fe.sup.3+,
Al.sup.3+, Ga.sup.3+, Y.sup.3+, In.sup.3+, Sb.sup.3+, Bi.sup.3+,
Si.sup.4+, Ti.sup.4+, V.sup.4+, Ge.sup.4+, M.sup.4+, pt.sup.4+,
V.sup.5+, Nb.sup.5+, Sb.sup.5+, or mixtures thereof. In one
embodiment the catalyst comprises Li.sup.+, Na.sup.+, or K.sup.+ as
monovalent cation, and Ca.sup.2+, Ba.sup.2+, or Mn.sup.3+ as
polyvalent cation; in another embodiment, the catalyst comprises
Na.sup.+ or K.sup.+ as monovalent cation, and Ca.sup.2+ or
Ba.sup.2+ as polyvalent cation; and in yet another embodiment, the
catalyst comprises K.sup.+ as the monovalent cation and Ba.sup.2+
as the polyvalent cation.
[0092] In one embodiment, the catalyst comprises
Ba.sub.2-x-sK.sub.2xH.sub.2sP.sub.2O.sub.7 and (KPO.sub.3).sub.n,
wherein x and s are greater or equal to 0 and less than about 0.5
and n is a positive integer. In another embodiment, the catalyst
comprises Ca.sub.2-x-sK.sub.2xH.sub.2sP.sub.2O.sub.7 and
(KPO.sub.3).sub.n, wherein x and s are greater or equal to 0 and
less than about 0.5 and n is at least 2. In yet another embodiment,
the catalyst comprises Mn.sub.1-x-sK.sub.1+3xH.sub.3sP.sub.2O.sub.7
or Mn.sub.1-x-sK.sub.2+2xH.sub.2sP.sub.2O.sub.7 and
(KPO.sub.3).sub.n wherein x and s are greater or equal to 0 and
less than about 0.5 and n is at least 2. In another embodiment, the
catalyst comprises any blend of
Ba.sub.2-x-sK.sub.2xH.sub.2P.sub.2O.sub.7,
Ca.sub.2-x-sK.sub.2xH.sub.2sP.sub.2O.sub.7,
Mn.sub.1-x-sK.sub.1+3xH.sub.3sP.sub.2O.sub.7 or
Mn.sub.1-x-sK.sub.2+2xH.sub.2sP.sub.2O.sub.7; and
(KPO.sub.3).sub.n, wherein x and s are greater or equal to 0 and
less than about 0.5 and n is at least 2.
[0093] In one embodiment, the catalyst comprises: (a) at least two
different condensed phosphate anions selected from the group
consisting of formulae (VI), (VII), and (VIII),
[P.sub.nO.sub.3n+1].sup.(n+2)- (VI)
[P.sub.nO.sub.3n].sup.n- (VII)
[P.sub.(2m+n)O.sub.(5m+3n)].sup.n- (VIII)
wherein n is at least 2 and m is at least 1, and (b) one cation,
wherein the catalyst is essentially neutrally charged, and further,
wherein the molar ratio of phosphorus to the cation is between
about 0.5 and about 4.0. In another embodiment, the molar ratio of
phosphorus to the cation is between about t/2 and about t, wherein
t is the charge of the cation.
[0094] The catalyst can include an inert support that is
constructed of a material comprising silicates, aluminates,
carbons, metal oxides, and mixtures thereof. Alternatively, the
carrier is inert relative to the reaction mixture expected to
contact the catalyst. In the context of the reactions expressly
described herein, in one embodiment the carrier is a low surface
area silica or zirconia. When present, the carrier represents an
amount of about 5 wt % to about 98 wt %, based on the total weight
of the catalyst. Generally, a catalyst that includes an inert
support can be made by one of two exemplary methods: impregnation
or co-precipitation. In the impregnation method, a suspension of
the solid inert support is treated with a solution of a
pre-catalyst, and the resulting material is then activated under
conditions that will convert the pre-catalyst to a more active
state. In the co-precipitation method, a homogenous solution of the
catalyst ingredients is precipitated by the addition of additional
ingredients.
[0095] In another embodiment, the catalyst can be sulfate salts;
phosphate salts; mixtures of sulfate and phosphate salts; bases;
zeolites or modified zeolites; metal oxides or modified metal
oxides; supercritical water, or mixtures thereof.
IV Catalyst Preparation Methods
[0096] In one embodiment, the method of preparing the catalyst
includes mixing at least two different phosphorus containing
compounds, wherein each said compound is described by one of the
formulae (IX) to (XXX), or any of the hydrated forms of said
formulae:
M.sup.I.sub.y(H.sub.3-yPO.sub.4) (IX)
M.sup.II.sub.y(H.sub.3-yPO.sub.4).sub.2 (X)
M.sup.III.sub.y(H.sub.3-yPO.sub.4).sub.3 (XI)
M.sup.IV.sub.y(H.sub.3-yPO.sub.4).sub.4 (XII)
(NH.sub.4).sub.y(H.sub.3-yPO.sub.4) (XIII)
M.sup.II.sub.a(OH).sub.b(PO.sub.4).sub.c (XIV)
M.sup.III.sub.d(OH).sub.e(PO.sub.4).sub.f (XV)
M.sup.IIM.sup.IPO.sub.4 (XVI)
M.sup.IIIM.sup.I.sub.3(PO.sub.4).sub.2 (XVII)
M.sup.IV.sub.2M.sup.I(PO.sub.4).sub.3 (XVIII)
M.sup.I.sub.zH.sub.4-zP.sub.2O.sub.7 (XIX)
M.sup.II.sub.vH.sub.(4-2v)P.sub.2O.sub.7 (XX)
M.sup.IVP.sub.2O.sub.7 (XXI)
(NH.sub.4).sub.zH.sub.4-zP.sub.2O.sub.7 (XXII)
M.sup.IIIM.sup.IP.sub.2O.sub.7 (XXIII)
M.sup.IH.sub.w(PO.sub.3).sub.(1+w) (XXIV)
M.sup.IIH.sub.w(PO.sub.3).sub.(2+w) (XXV)
M.sup.IIIH.sub.w(PO.sub.3).sub.(3+w) (XXVI)
M.sup.IVH.sub.w(PO.sub.3).sub.(4+w) (XXVII)
M.sup.II.sub.gM.sup.I.sub.h(PO.sub.3).sub.i (XXVIII)
M.sup.III.sub.jM.sup.I.sub.k(PO.sub.3).sub.i (XXIX)
P.sub.2O.sub.5 (XXX)
wherein M.sup.I s a monovalent cation; wherein M.sup.II is a
divalent cation; wherein M.sup.III is a trivalent cation; wherein
M.sup.IV is a tetravalent cation; wherein y is 0, 1, 2, or 3;
wherein z is 0, 1, 2, 3, or 4; wherein v is 0, 1, or 2; wherein w
is 0 or any positive integer; and wherein a, b, c, d, e, f, g, h,
i, j, k, and 1 are any positive integers, such that the equations:
2a=b+3c, 3d=e+3f, i=2g+h, and 1=3j+k are satisfied. In another
embodiment, the method of preparing the catalyst includes heating
the phosphorus-containing compounds after mixing. In another
embodiment, the method of preparing the catalyst includes
contacting the phosphorus-containing compounds after mixing, with a
gaseous mixture comprising water.
[0097] In one embodiment, the catalyst is prepared by the steps
including mixing one or more phosphorus containing compounds of
formula (IX), wherein y is equal to 1, and one or more phosphorus
containing compounds of formula (X), wherein y is equal to 2. In
another embodiment, the catalyst is prepared by the steps including
mixing M.sup.IH.sub.2PO.sub.4 and M.sup.IIHPO.sub.4. In one
embodiment, M.sup.I is K.sup.+ and M.sup.II is Ca.sup.2+, i.e., the
catalyst is prepared by mixing KH.sub.2PO.sub.4 and CaHPO.sub.4; or
M.sup.I is K and M.sup.II is Ba.sup.2+, i.e., the catalyst is
prepared by the steps including mixing KH.sub.2PO.sub.4 and
BaHPO.sub.4.
[0098] In one embodiment, the catalyst is prepared by the steps
including mixing one or more phosphorus containing compound of
formula (IX), wherein y is equal to 1, one or more phosphorus
containing compounds of formula (XX), wherein v is equal to 2. In
another embodiment, the catalyst is prepared by the steps including
mixing M.sup.IH.sub.2PO.sub.4 and M.sup.II.sub.2P.sub.2O.sub.7. In
one embodiment, M.sup.I is K.sup.+ and M.sup.II is Ca.sup.2+, i.e.,
the catalyst is prepared by mixing KH.sub.2PO.sub.4 and
Ca.sub.2P.sub.2O.sub.7; or M.sup.I is K.sup.+ and M.sup.II is
Ba.sup.2+, i.e., the catalyst is prepared by the steps including
mixing KH.sub.2PO.sub.4 and Ba.sub.2P.sub.2O.sub.7.
[0099] In another embodiment, the catalyst is prepared by the steps
including mixing one or more phosphorus-containing compounds of
formula (X), wherein said y is equal to 2, and one or more
phosphorus-containing compound of formula (XXIV), wherein said w is
equal to 0. In another embodiment, the phosphorus-containing
compounds are (KPO.sub.3).sub.n and BaHPO.sub.4 or CaHPO.sub.4;
wherein n is an integer greater than 2.
[0100] In yet another embodiment, the catalyst is prepared by the
steps including mixing one or more phosphorus-containing compounds
of formula (XX), wherein said v is equal to 2, and one or more
phosphorus-containing compound of formula (XXIV), wherein said w is
equal to 0. In another embodiment, the phosphorus-containing
compounds are (KPO.sub.3).sub.n and Ba.sub.2P.sub.2O.sub.7 or
Ca.sub.2P.sub.2O.sub.7; wherein n is an integer greater than 2.
[0101] In another embodiment, the molar ratio of phosphorus to the
cations in the catalyst is between about 0.7 and about 1.7; in yet
another embodiment, the molar ratio of phosphorus to the cations in
the catalyst is between about 0.8 and about 1.3; and in another
embodiment, the molar ratio of phosphorus to the cations in the
catalyst is about 1.
[0102] In another embodiment, the method of preparing the catalyst
includes mixing (a) at least one phosphorus containing compound,
wherein each said compound is described by one of the formulae (IX)
to (XXX), or any of the hydrated forms of said formulae:
M.sup.I.sub.y(H.sub.3-yPO.sub.4) (IX)
M.sup.II.sub.y(H.sub.3-yPO.sub.4).sub.2 (X)
M.sup.III.sub.y(H.sub.3-yPO.sub.4).sub.3 (XI)
M.sup.IV.sub.y(H.sub.3-yPO.sub.4).sub.4 (XII)
(NH.sub.4).sub.y(H.sub.3-yPO.sub.4) (XIII)
M.sup.II.sub.a(OH).sub.b(PO.sub.4).sub.c (XIV)
M.sup.III.sub.d(OH).sub.e(PO.sub.4).sub.f (XV)
M.sup.IIM.sup.IPO.sub.4 (XVI)
M.sup.IIIM.sup.I.sub.3(PO.sub.4).sub.2 (XVII)
M.sup.IV.sub.2M.sup.I(PO.sub.4).sub.3 (XVIII)
M.sup.I.sub.zH.sub.4-zP.sub.2O.sub.7 (XIX)
M.sup.II.sub.vH.sub.(4-2v)P.sub.2O.sub.7 (XX)
M.sup.IVP.sub.2O.sub.7 (XXI)
(NH.sub.4).sub.zH.sub.4-zP.sub.2O.sub.7 (XXII)
M.sup.IIIM.sup.IP.sub.2O.sub.7 (XXIII)
M.sup.IH.sub.w(PO.sub.3).sub.(1+w) (XXIV)
M.sup.IIH.sub.w(PO.sub.3).sub.(2+w) (XXV)
M.sup.IIIH.sub.w(PO.sub.3).sub.(3+w) (XXVI)
M.sup.IVH.sub.w(PO.sub.3).sub.(4+w) (XXVII)
M.sup.II.sub.gM.sup.I.sub.h(PO.sub.3).sub.i (XXVIII)
M.sup.III.sub.jM.sup.I.sub.k(PO.sub.3).sub.i (XXIX)
P.sub.2O.sub.5 (XXX)
wherein y is 0, 1, 2, or 3; wherein z is 0, 1, 2, 3, or 4; wherein
v is 0, 1, or 2; wherein w is 0 or any positive integer; and
wherein a, b, c, d, e, f, g, h, i, j, k, and 1 are any positive
integers, such that the equations: 2a=b+3c, 3d=e+3f, i=2g+h, and
1=3j+k are satisfied, and (b) at least one non-phosphorus
containing compound selected from the group consisting of nitrate
salts, carbonate salts, acetate salts, metal oxides, chloride
salts, sulfate salts, and metal hydroxides, wherein each said
compound is described by one of the formulae (XXVI) to (L), or any
of the hydrated forms of said formulae:
M.sup.INO.sub.3 (XXXI)
M.sup.II(NO.sub.3).sub.2 (XXXII)
M.sup.III(NO.sub.3).sub.3 (XXXIII)
M.sup.I.sub.2CO.sub.3 (XXXIV)
M.sup.IICO.sub.3 (XXXV)
M.sup.III.sub.2(CO.sub.3).sub.3 (XXXVI)
(CH.sub.3COO)M.sup.I (XXXVII)
(CH.sub.3COO).sub.2M.sup.II (XXXVIII)
(CH.sub.3COO).sub.3M.sup.III (XXXIX)
(CH.sub.3COO).sub.4M.sup.IV (XL)
M.sup.I.sub.2O (XLI)
M.sup.IIO (XLII)
M.sup.III.sub.2O.sub.3 (XLIII)
M.sup.IVO.sub.2 (XLIV)
M.sup.ICl (XLV)
M.sup.IICl.sub.2 (XLVI)
M.sup.IIICl.sub.3 (XLVII)
M.sup.IVCl.sub.4 (XLVIII)
M.sup.I.sub.2SO.sub.4 (XLIX)
M.sup.IISO.sub.4 (L)
M.sup.III.sub.2(SO.sub.4).sub.3 (LI)
M.sup.IV(SO.sub.4).sub.2 (LII)
M.sup.IOH (LIII)
M.sup.II(OH).sub.2 (LIV)
M.sup.III(OH).sub.3 (LV).
[0103] In another embodiment, the non-phosphorus containing
compounds can be selected from the group consisting of carboxylic
acid-derived salts, halide salts, metal acetylacetonates, and metal
alkoxides.
[0104] In another embodiment, the method of preparing the catalyst
includes contacting the phosphorus-containing and the
non-phosphorus-containing compounds after mixing, with a gaseous
mixture comprising water.
[0105] In one embodiment of the present invention, the molar ratio
of phosphorus to the cations in the catalyst is between about 0.7
and about 1.7; in another embodiment, the molar ratio of phosphorus
to the cations in the catalyst is between about 0.8 and about 1.3;
and in yet another embodiment, the molar ratio of phosphorus to the
cations in the catalyst is about 1.
[0106] In another embodiment of the present invention, the catalyst
is prepared by mixing and heating one or more phosphorus containing
compounds of formulae (IX) to (XXX) or their hydrated forms, and
one or more nitrate salts of formulae (XXXI) to (XXXIII) or their
hydrated forms. In another embodiment of the present invention, the
catalyst is prepared by mixing and heating one or more phosphorus
containing compounds of formula (IX) and one or more nitrate salts
of formula (XXXII). In a further embodiment of the present
invention, the catalyst is prepared by mixing and heating a
phosphorus containing compound of formula (IX) wherein y is equal
to 2, a phosphorus containing compound of formula (IX) wherein y is
equal to 0 (i.e., phosphoric acid), and a nitrate salt of formula
(XXXII). In yet another embodiment of the present invention, the
catalyst is prepared by mixing and heating K.sub.2HPO.sub.4,
H.sub.3PO.sub.4, and Ba(NO.sub.3).sub.2. In yet another embodiment,
the catalyst is prepared by mixing and heating K.sub.2HPO.sub.4,
H.sub.3PO.sub.4, and Ca(NO.sub.3).sub.2.
[0107] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (IX) and one or more nitrate salts of formula
(XXXIII). In a further embodiment of the present invention, the
catalyst is prepared by mixing and heating a phosphorus containing
compound of formula (IX) wherein y is equal to 2, a phosphorus
containing compound of formula (IX) wherein y is equal to 0 (i.e.,
phosphoric acid), and a nitrate salt of formula (XXXIII). In yet
another embodiment of the present invention, the catalyst is
prepared by mixing and heating K.sub.2HPO.sub.4, H.sub.3PO.sub.4,
and Mn(NO.sub.3).sub.2.4H.sub.2O.
[0108] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (X) and one or more nitrate salts of formula
(XXXI). In another embodiment of the present invention, the
catalyst is prepared by mixing and heating a phosphorus containing
compound of formula (X) wherein y is equal to 2, a phosphorus
containing compound of formula (X) wherein y is equal to 0 (i.e.,
phosphoric acid), and a nitrate salt of formula (XXXI). In yet
another embodiment of the present invention, the catalyst is
prepared by mixing and heating BaHPO.sub.4, H.sub.3PO.sub.4, and
KNO.sub.3. In another embodiment, 10 the catalyst is prepared by
mixing and heating CaHPO.sub.4, H.sub.3PO.sub.4, and KNO.sub.3.
[0109] In one embodiment of this invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (X), one or more phosphorus containing
compounds of formula (XX), and one or more nitrate salts of formula
(XXXI). In a further embodiment of this invention, the catalyst is
prepared by mixing and heating a phosphorus containing compound of
formula (X), wherein y is equal to 0 (i.e., phosphoric acid); a
phosphorus containing compound of formula (XX), wherein v is equal
to 2; and a nitrate salt of formula (XXXI). In another embodiment
of the present invention, the catalyst is prepared by mixing and
heating H.sub.3PO.sub.4, Ca.sub.2P.sub.2O.sub.7, and KNO.sub.3. In
yet another embodiment, the catalyst is prepared by mixing and
heating H.sub.3PO.sub.4, Ba.sub.2P.sub.2O.sub.7, and KNO.sub.3.
[0110] In another embodiment of this invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (XI) and one or more nitrate salts of formula
(XXXI). In another embodiment of this invention, the catalyst is
prepared by mixing and heating a phosphorus containing compound of
formula (XI), wherein y is equal to 3; a phosphorus containing
compound of formula (XI), wherein y is equal to 0 (i.e., phosphoric
acid); and a nitrate salt of formula (XXXI). In yet another
embodiment of this invention, the catalyst is prepared by mixing
and heating MnPO.sub.4.qH.sub.2O, H.sub.3PO.sub.4, and
KNO.sub.3.
[0111] In one embodiment of this invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (IX), one or more phosphorus containing
compounds of formula (XIV), and one or more nitrate salts of
formula (XXXII). In another embodiment of this invention, the
catalyst is prepared by mixing and heating a phosphorus containing
compound of formula (IX), wherein y is equal to 2; a phosphorus
containing compound of formula (IX), wherein y is equal to 0 (i.e.,
phosphoric acid); a phosphorus containing compound of formula
(XIV), wherein a is equal to 2, b is equal to 1, and c is equal to
1; and a nitrate salt of formula (XXXII). In yet another embodiment
of this invention, the catalyst is prepared by mixing and heating
K.sub.2HPO.sub.4, H.sub.3PO.sub.4, Cu.sub.2(OH)PO.sub.4, and
Ba(NO.sub.3).sub.2.
[0112] In one embodiment of this invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (X), one or more phosphorus containing
compounds of formula (XIV), and one or more nitrate salts of
formula (XXXI). In another embodiment of this invention, the
catalyst is prepared by mixing and heating a phosphorus containing
compound of formula (X), wherein y is equal to 3; a phosphorus
containing compound of formula (X), wherein y is equal to 0 (i.e.,
phosphoric acid); a phosphorus containing compound of formula
(XIV), wherein a is equal to 2, b is equal to 1, and c is equal to
1; and a nitrate salt of formula (XXXI). In yet another embodiment,
the catalyst is prepared by mixing and heating
Ba.sub.3(PO.sub.4).sub.2, H.sub.3PO.sub.4, Cu.sub.2(OH)PO.sub.4,
and KNO.sub.3.
[0113] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds described by one of the formulae (IX) to (XXX) or any of
the hydrated forms, and one or more carbonate salts described by
one of the formulae (XXXIV) to (XXXVI) or any of the hydrated
forms.
[0114] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds described by one of the formulae (IX) to (XXX) or any of
the hydrated forms, and one or more acetate salts described by one
of the formulae (XXXVII) to (XL), any other organic acid-derived
salts, or any of the hydrated forms.
[0115] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds described by one of the formulae (IX) to (XXX) or any of
the hydrated forms, and one or more metal oxides described by one
of the formulae (XLI) to (XLIV) or any of the hydrated forms.
[0116] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds described by one of the formulae (IX) to (XXX) or any of
the hydrated forms, and one or more chloride salts described by one
of the formulae (XLV) to (XLVIII), any other halide salts, or any
of the hydrated forms.
[0117] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds described by one of the formulae (IX) to (XXX) or any of
the hydrated forms, and one or more sulfate salts described by one
of the formulae (XLIX) to (LII) or any of the hydrated forms.
[0118] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds described by one of the formulae (IX) to (XXX) or any of
the hydrated forms, and one or more hydroxides described by one of
the formulae (LIII) to (LV) or any of the hydrated forms.
[0119] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formulae (IX) to (XXX), and two or more non-phosphorus
containing compounds of formulae (XXXI) to (LV) or their hydrated
forms.
[0120] In one embodiment of the present invention, the method of
preparing the catalyst includes contacting: (a) a gaseous mixture
comprising water, with (b) a mixture of compounds containing at
least one condensed phosphate anion selected from the group
consisting of formulae (VI) to (VIII),
[P.sub.nO.sub.3n+1].sup.(n+2)- (VI)
[P.sub.nO.sub.3n].sup.n- (VII)
[P.sub.(2m+n)O.sub.(5m+3n)].sup.n- (VIII)
wherein n is at least 2; wherein m is at least 1; wherein, said
mixture of compounds is essentially neutrally charged; and further,
wherein the molar ratio of phosphorus to the monovalent and
polyvalent cations in the catalyst is between about 0.7 and about
1.7. In another embodiment, the molar ratio of phosphorus to the
monovalent and polyvalent cations is about 1.
[0121] In yet another embodiment, the catalyst is prepared by the
steps including contacting: (a) a gaseous mixture comprising water,
with (b) a mixture of compounds containing a condensed phosphate
salt selected from the group consisting of
Ba.sub.2-x-sK.sub.2xH.sub.2sP.sub.2O.sub.7,
Ca.sub.2-x-sK.sub.2xH.sub.2sP.sub.2O.sub.7,
Mn.sub.1-x-sK.sub.1+3xH.sub.3sP.sub.2O.sub.7,
Mn.sub.1-x-sK.sub.2+2xH.sub.2sP.sub.2O.sub.7, and mixtures thereof;
and (KPO.sub.3).sub.n; wherein x and s are greater or equal to 0
and less than about 0.5 and n is at least 2.
[0122] In one embodiment, the molar ratio of phosphorus to the
cations (i.e., M.sup.I+M.sup.II+M.sup.III+ . . . ) is between about
0.7 and about 1.7; in another embodiment, the molar ratio of
phosphorus to the cations (i.e., M.sup.I+M.sup.II+M.sup.III+ . . .
) is between about 0.8 and about 1.3, and in yet another
embodiment, the molar ratio of phosphorus to the cations (i.e.,
M.sup.I+M.sup.II+M.sup.III+ . . . ) is about 1. For example, in an
embodiment when the catalyst includes potassium (K.sup.+) and
barium (Ba.sup.2+), the molar ratio between phosphorus and the
metals (K+Ba) is between about 0.7 and about 1.7; and in another
embodiment, the molar ratio between phosphorus and the metals
(K+Ba) is about 1.
[0123] In one embodiment, the catalyst can include an inert support
that is constructed of a material comprising silicates, aluminates,
carbons, metal oxides, and mixtures thereof. Alternatively, the
carrier is inert relative to the reaction mixture expected to
contact the catalyst. In another embodiment, the method of
preparing the catalyst can further include mixing an inert support
with the catalyst before, during, or after the mixing and heating
of the phosphorus containing compounds, wherein the inert support
includes silicates, aluminates, carbons, metal oxides, and mixtures
thereof. In yet another embodiment, the method of preparing the
catalyst can further include mixing an inert support with the
catalyst before, during, or after the mixing and heating of the
phosphorus containing compounds and the non-phosphorus containing
compounds, wherein the inert support includes silicates,
aluminates, carbons, metal oxides, and mixtures thereof.
[0124] Mixing of the phosphorus containing compounds or the
phosphorus containing and non-phosphorus containing compounds of
the catalyst can be performed by any method known to those skilled
in the art, such as, by way of example and not limitation: solid
mixing and co-precipitation. In the solid mixing method, the
various components are physically mixed together with optional
grinding using any method known to those skilled in the art, such
as, by way of example and not limitation, shear, extensional,
kneading, extrusion, and others. In the co-precipitation method, an
aqueous solution or suspension of the various components, including
one or more of the phosphate compounds, is prepared, followed by
optional filtration and heating to remove solvents and volatile
materials (e.g., water, nitric acid, carbon dioxide, ammonia, or
acetic acid). The heating is typically done using any method known
to those skilled in the art, such as, by way of example and not
limitation, convection, conduction, radiation, microwave heating,
and others.
[0125] In one embodiment of the invention, the catalyst is
calcined. Calcination is a process that allows chemical reaction
and/or thermal decomposition and/or phase transition and/or removal
of volatile materials. The calcination process is carried out with
any equipment known to those skilled in the art, such as, by way of
example and not limitation, furnaces or reactors of various
designs, including shaft furnaces, rotary kilns, hearth furnaces,
and fluidized bed reactors. The calcination temperature is, in one
embodiment, about 200.degree. C. to about 1200.degree. C.; in
another embodiment, the calcination temperature is about
250.degree. C. to about 900.degree. C.; and in yet another
embodiment, the calcination temperature is about 300.degree. C. to
600.degree. C. The calcination time is, in one embodiment, about
one hour to about seventy-two hours.
[0126] While many methods and machines are known to those skilled
in the art for fractionating particles into discreet sizes and
determining particle size distribution, sieving is one of the
easiest, least expensive, and common ways. An alternative way to
determine the size distribution of particles is with light
scattering. Following calcination, the catalyst is, in one
embodiment, ground and sieved to provide a more uniform product.
The particle size distribution of the catalyst particles includes a
particle span that, in one embodiment, is less than about 3; in
another embodiment, the particle size distribution of the catalyst
particles includes a particle span that is less than about 2; and
in yet another embodiment, the particle size distribution of the
catalyst particles includes a particle span that is less than about
1.5. In another embodiment of the invention, the catalyst is sieved
to a median particle size of about 50 .mu.m to about 500 .mu.m. In
another embodiment of the invention, the catalyst is sieved to a
median particle size of about 100 .mu.m to about 200 .mu.m.
[0127] In one embodiment of the present invention, the catalyst is
prepared by the steps including combining BaHPO.sub.4 and
KH.sub.2PO.sub.4 in a molar ratio between about 3:2 and about 2:3
to form a solid mixture, and grinding said solid mixture to produce
the catalyst.
[0128] In another embodiment of the present invention, the catalyst
is prepared by the steps including: (a) combining BaHPO.sub.4 and
KH.sub.2PO.sub.4 in a molar ratio between about 3:2 and about 2:3
to form a solid mixture; (b) grinding said solid mixture to produce
a mixed powder; (c) calcining said mixed powder at about
550.degree. C. to produce a condensed phosphate mixture; and (d)
contacting said condensed phosphate mixture with a gaseous mixture
comprising water and lactic acid at a 15 temperature of about
350.degree. C. and a total pressure of about 25 bar to produce said
catalyst, and wherein the partial pressure of water in said gaseous
mixture is about 12.5 bar.
[0129] In another embodiment, the catalyst is prepared by the
following steps, which comprise: (a) combining a phosphorus
containing compound, a nitrate salt, phosphoric acid, and water to
form a wet mixture, wherein the molar ratio between phosphorus and
the cations in both said phosphorus containing compound and said
nitrate salt is about 1, (b) calcining said wet mixture stepwise at
about 50.degree. C., about 80.degree. C., about 120.degree. C., and
about 450.degree. C. to about 550.degree. C. to produce a dried
solid, and (c) grinding and sieving said dried solid to about 100
.mu.m to about 200 .mu.m, to produce said catalyst.
[0130] In another embodiment, the catalyst is prepared by the
following steps, which comprise: (a) combining
MnPO.sub.4.qH.sub.2O, KNO.sub.3, and H.sub.3PO.sub.4, in a molar
ratio of about 0.3:1:1, on an anhydrous basis, and water to give a
wet mixture, (b) calcining said wet mixture stepwise at about
50.degree. C., about 80.degree. C., about 120.degree. C., and about
450.degree. C. to about 550.degree. C. to give a dried solid, and
(c) grinding and sieving said dried solid to about 100 .mu.m to
about 200 .mu.m, to produce said catalyst.
[0131] In another embodiment, the catalyst is prepared by the
following steps, which comprise: (a) combining
Ca.sub.2P.sub.2O.sub.7, KNO.sub.3, and H.sub.3PO.sub.4, in a molar
ratio of about 1.6:1:1, and water to give a wet mixture, (b)
calcining said wet mixture stepwise at about 50.degree. C., about
80.degree. C., about 120.degree. C., and about 450.degree. C. to
about 550.degree. C. to give a dried solid, and (c) grinding and
sieving said dried solid to about 100 .mu.m to about 200 .mu.m, to
produce said catalyst.
[0132] In another embodiment, the catalyst is prepared by the
following steps, which comprise: (a) combining a phosphorus
containing compound, a nitrate salt, phosphoric acid, and water to
give a wet mixture, wherein the molar ratio between phosphorus and
the cations in both the phosphorus containing compound and nitrate
salt is about 1, (b) heating said wet mixture to about 80.degree.
C. with stirring until near dryness to form a wet solid, (c)
calcining said wet solid stepwise at about 50.degree. C., about
80.degree. C., about 120.degree. C., and about 450.degree. C. to
about 550.degree. C. to give a dried solid, and (d) grinding and
sieving said dried solid to about 100 .mu.m to about 200 .mu.m, to
produce said catalyst.
[0133] In another embodiment, the catalyst is prepared by the
following steps, which comprise: (a) combining Ba(NO.sub.3).sub.2,
K.sub.2HPO.sub.4, and H.sub.3PO.sub.4, in a molar ratio of about
3:1:4, and water to give a wet mixture, (b) heating said wet
mixture to about 80.degree. C. with stirring until near dryness to
form a wet solid, (c) calcining said wet solid stepwise at about
50.degree. C., about 80.degree. C., about 120.degree. C., and about
450.degree. C. to about 550.degree. C. to give a dried solid, and
(d) grinding and sieving said dried solid to about 100 .mu.m to
about 200 .mu.m, to produce said catalyst.
[0134] In yet another embodiment of the present invention, the
catalyst is prepared by the steps including: (a) combining
K.sub.2HPO.sub.4, Ba(NO.sub.3).sub.2, H.sub.3PO.sub.4, and water to
form a wet mixture, wherein the molar ratio of Ba(NO.sub.3).sub.2,
K.sub.2HPO.sub.4, and H.sub.3PO.sub.4 is about 3:1:4; (b) heating
said wet mixture to about 80.degree. C. with stirring until near
dryness to form a wet solid; (c) calcining said wet solid stepwise
at about 50.degree. C., about 80.degree. C., about 120.degree. C.,
and about 450.degree. C. to about 550.degree. C. to produce a dried
solid; and (d) contacting said dried solid with a gaseous mixture
comprising water and lactic acid at a temperature of about
350.degree. C. and a total pressure of about 25 bar to produce said
catalyst, and wherein the partial pressure of water in said gaseous
mixture is about 12.5 bar.
[0135] In another embodiment, the catalyst is prepared by the
following steps, which comprise: (a) combining
Mn(NO.sub.3).sub.2.4H.sub.2O, K.sub.2HPO.sub.4, and
H.sub.3PO.sub.4, in a molar ratio of about 1:1.5:2, and water to
give a wet mixture, (b) heating said wet mixture to about
80.degree. C. with stirring until near dryness to form a wet solid,
(c) calcining said wet solid stepwise at about 50.degree. C., about
80.degree. C., about 120.degree. C., and about 450.degree. C. to
about 550.degree. C. to give a dried solid, and (d) grinding and
sieving said dried solid to about 100 .mu.m to about 200 .mu.m, to
produce said catalyst.
[0136] In another embodiment, the catalyst is prepared by the
following steps, which comprise: (a) combining
Ca.sub.2P.sub.2O.sub.7 and KH.sub.2PO.sub.4 in a molar ratio of
about 3:1 to give a solid mixture, and (b) calcining said solid
mixture stepwise at about 50.degree. C., about 80.degree. C., about
120.degree. C., and about 450.degree. C. to about 550.degree. C.,
to produce said catalyst.
[0137] Following calcination and optional grinding and sieving, the
catalyst can be utilized to catalyze several chemical reactions.
Non-limiting examples of reactions are: dehydration of
hydroxypropionic acid to acrylic acid (as described in further
detail below), dehydration of glycerin to acrolein, dehydration of
aliphatic alcohols to alkenes or olefins, dehydrogenation of
aliphatic alcohols to ethers, other dehydrogenations, hydrolyses,
alkylations, dealkylations, oxidations, disproportionations,
esterifications, cyclizations, isomerizations, condensations,
aromatizations, polymerizations, and other reactions that may be
apparent to those having ordinary skill in the art.
V Process for the Production of Acrylic Acid or its Derivatives
from Hydroxypropionic Acid or its Derivatives
[0138] A process for converting hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof to acrylic
acid, acrylic acid derivatives, or mixtures thereof of the present
invention comprises the following steps: a) providing an aqueous
solution comprising hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof, wherein the hydroxypropionic acid
is in monomeric form in the aqueous solution; b) combining the
aqueous solution with an inert gas to form an aqueous solution/gas
blend; c) evaporating the aqueous solution gas/blend to produce a
gaseous mixture; and d) dehydrating the gaseous mixture by
contacting the mixture with a dehydration catalyst under a pressure
of at least about 80 psig.
[0139] Hydroxypropionic acid can be 3-hydroxypropionic acid,
2-hydroxypropionic acid (also called, lactic acid), 2-methyl
hydroxypropionic acid, or mixtures thereof. Derivatives of
hydroxypropionic acid can be metal or ammonium salts of
hydroxypropionic acid, alkyl esters of hydroxypropionic acid, alkyl
esters of 2-methyl hydroxypropionic acid, cyclic di-esters of
hydroxypropionic acid, hydroxypropionic acid anhydride, or a
mixture thereof. Non-limiting examples of metal salts of
hydroxypropionic acid are sodium hydroxypropionate, potassium
hydroxypropionate, and calcium hydroxypropionate. Non-limiting
examples of alkyl esters of hydroxypropionic acid are methyl
hydroxypropionate, ethyl hydroxypropionate, butyl
hydroxypropionate, 2-ethylhexyl hydroxypropionate, or mixtures
thereof. A non-limiting example of cyclic di-esters of
hydroxypropionic acid is dilactide.
[0140] Hydroxypropionic acid can be in monomeric form or as
oligomers in an aqueous solution of hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof. In one
embodiment, the oligomers of the hydroxypropionic acid in an
aqueous solution of hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof are less than about 25 wt % based
on the total amount of hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof. In another embodiment, the
oligomers of the hydroxypropionic acid in an aqueous solution of
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof are less than about 10 wt % based on the total
amount of hydroxypropionic acid, hydroxypropionic acid derivatives,
or mixtures thereof. In another embodiment, the oligomers of the
hydroxypropionic acid in an aqueous solution of hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof are
less than about 5 wt % based on the total amount of
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof. In yet another embodiment, the hydroxypropionic
acid is in monomeric form in an aqueous solution of
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof. The process steps to remove the oligomers from
the aqueous solution can be purification or diluting with water and
heating. In one embodiment, the heating step can involve heating
the aqueous solution of hydroxypropionic acid, hydroxypropionic
acid derivatives, or mixtures thereof at a temperature from about
50.degree. C. to about 100.degree. C. to remove the oligomers of
the hydroxypropionic acid. In another embodiment, the heating step
can involve heating the lactic acid aqueous solution at a
temperature from about 95.degree. C. to about 100.degree. C. to
remove the oligomers of the lactic acid and produce a monomeric
lactic acid aqueous solution comprising at least 95 wt % of lactic
acid in monomeric form based on the total amount of lactic acid. In
another embodiment, an about 88 wt % lactic acid aqueous solution
(e.g. from Purac Corp., Lincolnshire, Ill.) is diluted with water
to form an about 20 wt % lactic acid aqueous solution, to remove
the ester impurities that are produced from the intermolecular
condensation reaction. These esters can result in loss of product
due to their high boiling point and oligomerization in the
evaporation stage of the process. Additionally, these esters can
cause coking, catalyst deactivation, and reactor plugging. As the
water content decreases in the aqueous solution, the loss of feed
material to the catalytic reaction, due to losses in the
evaporation step, increases.
[0141] In one embodiment, the hydroxypropionic acid is lactic acid
or 2-methyl lactic acid. In another embodiment, the
hydroxypropionic acid is lactic acid. Lactic acid can be L-lactic
acid, D-lactic acid, or mixtures thereof. In one embodiment, the
hydroxypropionic acid derivative is methyl lactate. Methyl lactate
can be neat or in an aqueous solution.
[0142] Acrylic acid derivatives can be metal or ammonium salts of
acrylic acid, alkyl esters of acrylic acid, acrylic acid oligomers,
or a mixture thereof. Non-limiting examples of metal salts of
acrylic acid are sodium acrylate, potassium acrylate, and calcium
acrylate. Non-limiting examples of alkyl esters of acrylic acid are
methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl
acrylate, or mixtures thereof.
[0143] In one embodiment, the concentration of the hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof in the
aqueous solution is between about 5 wt % and about 50 wt %. In
another embodiment, the concentration of the hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof in the
aqueous solution is between about 10 wt % and about 25 wt %. In yet
another embodiment, the concentration of the hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof in the
aqueous solution is about 20 wt %.
[0144] The aqueous solution can be combined with an inert gas to
form an aqueous solution/gas blend. Non-limiting examples of the
inert gas are air, nitrogen, helium, argon, carbon dioxide, carbon
monoxide, steam, and mixtures thereof. The inert gas can be
introduced to the evaporating step separately or in combination
with the aqueous solution. The aqueous solution can be introduced
with a simple tube or through atomization nozzles. Non-limiting
examples of atomization nozzles include fan nozzles, pressure swirl
atomizers, air blast atomizers, two-fluid atomizers, rotary
atomizers, and supercritical carbon dioxide atomizers. In one
embodiment, the droplets of the aqueous solution are less than
about 500 .mu.m in diameter. In another embodiment, the droplets of
the aqueous solution are less than about 200 .mu.m in diameter. In
yet another embodiment, the droplets of the aqueous solution are
less than about 100 .mu.m in diameter.
[0145] In the evaporating step, the aqueous solution/gas blend is
heated to give a gaseous mixture. In one embodiment, the
temperature during the evaporating step is from about 165.degree.
C. to about 450.degree. C. In another embodiment, the temperature
during the evaporating step is from about 250.degree. C. to about
375.degree. C. In one embodiment, the gas hourly space velocity
(GHSV) in the evaporating step is from about 720 h.sup.-1 to 3,600
h.sup.-1. In another embodiment, the gas hourly space velocity
(GHSV) in the evaporating step is about 7,200 h.sup.-1. The
evaporating step can be performed at either atmospheric pressure or
higher pressure. In one embodiment, the evaporating step is
performed under a pressure from about 80 psig to about 550 psig. In
another embodiment, the evaporating step is performed under a
pressure from about 300 psig to about 400 psig. In yet another
embodiment, the evaporating step is performed under a pressure from
about 350 psig to about 375 psig. In one embodiment, the gaseous
mixture comprises from about 0.5 mol % to about 50 mol %
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof. In another embodiment, the gaseous mixture
comprises from about 1 mol % to about 10 mol % hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof. In
another embodiment, the gaseous mixture comprises from about 1.5
mol % to about 3.5 mol % hydroxypropionic acid, hydroxypropionic
acid derivatives, or mixtures thereof. In another embodiment, the
gaseous mixture comprises about 2.5 mol % hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof.
[0146] The evaporating step can be performed in various types of
equipment, such as, but not limited to, plate heat exchanger, empty
flow reactor, and fixed bed flow reactor. Regardless of the type of
the reactor, in one embodiment, the reactor has an interior surface
comprising material selected from the group consisting of quartz,
borosilicate glass, silicon, hastelloy, inconel, manufactured
sapphire, stainless steel, and mixtures thereof. In another
embodiment, the reactor has an interior surface comprising material
selected from the group consisting of quartz, borosilicate glass,
and mixtures thereof. The evaporating step can be performed in a
reactor with the aqueous solution flowing down, or flowing up, or
flowing horizontally. In one embodiment, the evaporating step is
performed in a reactor with the aqueous solution flowing down.
Also, the evaporating step can be done in a batch form.
[0147] The gaseous mixture from the evaporating step is converted
to acrylic acid, acrylic acid derivatives, and mixture thereof by
contact it with a dehydration catalyst in the dehydrating step. The
dehydration catalyst can be selected from the group comprising
sulfates, phosphates, metal oxides, aluminates, silicates,
aluminosilicates (e.g., zeolites), arsenates, nitrates, vanadates,
niobates, tantalates, selenates, arsenatophosphates,
phosphoaluminates, phosphoborates, phosphocromates,
phosphomolybdates, phosphosilicates, phosphosulfates,
phosphotungstates, and mixtures thereof, and others that may be
apparent to those having ordinary skill in the art. The catalyst
can contain an inert support that is constructed of a material
comprising silicates, aluminates, carbons, metal oxides, and
mixtures thereof. In one embodiment, the dehydrating step is
performed in a reactor, wherein the reactor has an interior surface
comprising material selected from the group consisting of quartz,
borosilicate glass, silicon, hastelloy, inconel, manufactured
sapphire, stainless steel, and mixtures thereof. In another
embodiment, the dehydrating step is performed in a reactor, wherein
the reactor has an interior surface comprising material selected
from the group consisting of quartz, borosilicate glass, and
mixtures thereof. In one embodiment, the temperature during the
dehydrating step is from about 150.degree. C. to about 500.degree.
C. In another embodiment, the temperature during the dehydrating
step is from about 300.degree. C. to about 450.degree. C. In one
embodiment, the GHSV in the dehydrating step is from about 720
h.sup.-1 to about 36,000 h.sup.-1. In another embodiment, the GHSV
in the dehydrating step is about 3,600 h.sup.-1. The dehydrating
step can be performed at higher than atmospheric pressure. In one
embodiment, the dehydrating step is performed under a pressure of
at least about 80 psig. In another embodiment, the dehydrating step
is performed under a pressure from about 80 psig to about 550 psig.
In another embodiment, the dehydrating step is performed under a
pressure from about 150 psig to about 500 psig. In yet another
embodiment, the dehydrating step is performed under a pressure from
about 300 psig to about 400 psig. The dehydrating step can be
performed in a reactor with the gaseous mixture flowing down,
flowing up, or flowing horizontally. In one embodiment, the
dehydrating step is performed in a reactor with the gaseous mixture
flowing down. Also, the dehydrating step can be done in a batch
form.
[0148] In one embodiment, the evaporating and dehydrating steps are
combined in a single step. In another embodiment, the evaporating
and dehydrating steps are performed sequentially in a single
reactor. In yet another embodiment, the evaporating and dehydrating
steps are performed sequentially in a tandem reactor.
[0149] In one embodiment, the selectivity of acrylic acid, acrylic
acid derivatives, and mixture thereof from hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof is at least
about 50%. In another embodiment, the selectivity of acrylic acid,
acrylic acid derivatives, and mixture thereof from hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof is at
least about 80%. In one embodiment, the selectivity of propanoic
acid from hydroxypropionic acid, hydroxypropionic acid derivatives,
or mixtures thereof is less than about 5%. In another embodiment,
the selectivity of propanoic acid from hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof is less than
about 1%. In one embodiment, the conversion of the hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof is
more than about 50%. In another embodiment, the conversion of the
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof is more than about 80%.
[0150] In another embodiment of the present invention, a process
for converting hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof to acrylic acid, acrylic acid
derivatives, or mixtures thereof is provided. The process comprises
the following steps: a) providing an aqueous solution comprising
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof, wherein the hydroxypropionic acid comprises
oligomers in the aqueous solution; b) heating the aqueous solution
at a temperature from about 50.degree. C. to about 100.degree. C.
to remove the oligomers of the hydroxypropionic acid and produce an
aqueous solution of monomeric hydroxypropionic acid; c) combining
the aqueous solution of monomeric hydroxypropionic acid with an
inert gas to form an aqueous solution/gas blend; d) evaporating the
aqueous solution gas/blend to produce a gaseous mixture; and e)
dehydrating the gaseous mixture by contacting the mixture with a
dehydration catalyst and producing the acrylic acid, acrylic acid
derivatives, or mixtures thereof.
[0151] In one embodiment, after the heating step, the concentration
of the oligomers of the hydroxypropionic acid in the aqueous
solution of monomeric of monomeric hydroxypropionic acid is less
than about 20 wt % based on the total amount of hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof. In
another embodiment, after the heating step, the concentration of
the oligomers of the hydroxypropionic acid in the aqueous solution
of monomeric of monomeric hydroxypropionic acid is less than about
5 wt % based on the total amount of hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof.
[0152] In another embodiment of the present invention, a process
for converting hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof to acrylic acid, acrylic acid
derivatives, and mixture thereof is provided. The process comprises
the following steps: a) providing an aqueous solution comprising
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof, wherein the hydroxypropionic acid is in monomeric
form in the aqueous solution; b) combining the aqueous solution
with an inert gas to form an aqueous solution/gas blend; c)
evaporating the aqueous solution/gas blend to produce a gaseous
mixture; d) dehydrating the gaseous mixture by contacting the
mixture with a dehydration catalyst producing acrylic acid, and/or
acrylates; and e) cooling the acrylic acid, acrylic acid
derivatives, and mixture thereof at a GHSV of more than about 360
h.sup.-1.
[0153] The stream of acrylic acid, acrylic acid derivatives, and
mixture thereof produced in the dehydrating step is cooled to give
an aqueous acrylic acid composition as the product stream. The time
required to cool stream of the acrylic acid, acrylic acid
derivatives, or mixtures thereof must be controlled to reduce the
decomposition of acrylic acid to ethylene and polymerization. In
one embodiment, the GHSV of the acrylic acid, acrylic acid
derivatives, and mixture thereof in the cooling step is more than
about 720 h.sup.-1.
[0154] In another embodiment of the present invention, a process
for converting lactic acid to acrylic acid is provided. The process
comprises the following steps: a) diluting an about 88 wt % lactic
acid aqueous solution with water to form an about 20 wt % lactic
acid aqueous solution; b) heating the about 20 wt % lactic acid
aqueous solution at a temperature of about 95.degree. C. to about
100.degree. C. to remove oligomers of the lactic acid, producing a
monomeric lactic acid solution comprising at least about 95 wt % of
the lactic acid in monomeric form based on the total amount of
lactic acid; c) combining the monomeric lactic acid solution with
nitrogen to form an aqueous solution/gas blend; d) evaporating the
aqueous solution/gas blend in a reactor with inside surface of
borosilicate glass at a GHSV of about 7,200 h.sup.-1 at a
temperature from about 300.degree. C. to about 350.degree. C. to
produce a gaseous mixture comprising about 2.5 mol % lactic acid
and about 50 mol % water; e) dehydrating the gaseous mixture in a
reactor with inside surface of borosilicate glass at a GHSV of
about 3,600 h.sup.-1 at a temperature of 350.degree. C. to about
425.degree. C. by contacting the mixture with a dehydration
catalyst under a pressure of about 360 psig, producing the acrylic
acid; and f) cooling the acrylic acid at a GHSV from about 360
h.sup.-1 to about 36,000 h.sup.-1.
[0155] In another embodiment of the present invention, a process
for converting hydroxypropionic acid, derivatives of
hydroxypropionic acid, and mixtures thereof to acrylic acid,
acrylic acid derivatives, or mixtures thereof is provided. The
process comprises the following steps: a) providing an aqueous
solution comprising hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof, wherein the hydroxypropionic acid
is in monomeric form in the aqueous solution, and wherein the
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof comprise from about 10 wt % to about 25 wt % of
the aqueous solution; b) combining the aqueous solution with an
inert gas to form an aqueous solution/gas blend; c) evaporating the
aqueous solution/gas blend to produce a gaseous mixture; and d)
dehydrating the gaseous mixture by contacting the mixture with a
dehydration catalyst producing acrylic acid, acrylic acid
derivatives, or mixtures thereof.
[0156] In another embodiment of the present invention, a process
for converting alkyl lactates to acrylic acid, acrylic acid
derivatives, or mixtures thereof is provided. The process comprises
the following steps: a) providing alkyl lactates or a solution
comprising alkyl lactates and a solvent; b) combining the alkyl
lactates or the solution comprising the alkyl lactates and the
solvent with an inert gas to form a liquid/gas blend; c)
evaporating the liquid/gas blend to produce a gaseous mixture; and
d) dehydrating the gaseous mixture by contacting the gaseous
mixture with a dehydration catalyst under a pressure of at least
about 80 psig, producing acrylic acid, acrylic acid derivatives, or
mixtures thereof.
[0157] In one embodiment, alkyl lactates are selected from the
group consisting of methyl lactate, ethyl lactate, butyl lactate,
2-ethylhexyl lactate, and mixtures thereof. In another embodiment,
the solvent is selected from the group consisting of water,
methanol, ethanol, butanol, 2-ethylhexanol, isobutanol, isooctyl
alcohol, and mixtures thereof.
[0158] In another embodiment, a process for converting
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof to acrylic acid, acrylic acid derivatives, or
mixtures thereof is provided comprising the following steps: a)
providing a solution comprising hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof; b)
combining the solution with a gas to form a solution/gas blend; and
c) dehydrating the solution/gas blend by contacting the
solution/gas blend with a dehydration catalyst.
VI Purification of Bio-Based Acrylic Acid to Crude and Glacial
Acrylic Acid
[0159] In one embodiment, a glacial acrylic acid composition is
provided comprising at least about 98 wt % acrylic acid, and
wherein a portion of the remaining impurities in the glacial
acrylic acid composition is hydroxypropionic acid, hydroxypropionic
acid derivatives, or mixtures thereof.
[0160] In one embodiment, a crude acrylic acid composition is
provided comprising between about 94 wt % and about 98 wt % acrylic
acid, and wherein a portion of the remaining impurities in the
glacial acrylic acid composition is hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof.
[0161] Hydroxypropionic acid can be 3-hydroxypropionic acid,
2-hydroxypropionic acid (also called, lactic acid), 2-methyl
hydroxypropionic acid, or mixtures thereof. Derivatives of
hydroxypropionic acid can be metal or ammonium salts of
hydroxypropionic acid, alkyl esters of hydroxypropionic acid, alkyl
esters of 2-methyl hydroxypropionic acid, cyclic di-esters of
hydroxypropionic acid, hydroxypropionic acid anhydride, or a
mixture thereof. Non-limiting examples of metal salts of
hydroxypropionic acid are sodium hydroxypropionate, potassium
hydroxypropionate, and calcium hydroxypropionate. Non-limiting
examples of alkyl esters of hydroxypropionic acid are methyl
hydroxypropionate, ethyl hydroxypropionate, butyl
hydroxypropionate, 2-ethylhexyl hydroxypropionate, or mixtures
thereof. A non-limiting example of cyclic di-esters of
hydroxypropionic acid is dilactide.
[0162] In one embodiment, the hydroxypropionic acid is lactic acid
or 2-methyl lactic acid. In another embodiment, the
hydroxypropionic acid is lactic acid. Lactic acid can be L-lactic
acid, D-lactic acid, or mixtures thereof. In one embodiment, the
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof in the impurities in the glacial acrylic acid
composition are lactic acid, lactic acid derivatives, or mixtures
thereof. In another embodiment, the hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof in the
impurities in the crude acrylic acid composition are lactic acid,
lactic acid derivatives, or mixtures thereof.
[0163] In one embodiment, the concentration of the hydroxypropionic
acid, hydroxypropionic acid derivatives, or mixtures thereof in the
remaining impurities of the glacial acrylic acid composition is
less than about 2 wt %, based on the total amount of the glacial
acrylic acid composition. In another embodiment, the
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof in the remaining impurities of the glacial acrylic
acid composition is less than about 1 wt %, based on the total
amount of the glacial acrylic acid composition. In another
embodiment, the hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof in the remaining impurities of the
glacial acrylic acid composition is less than about 400 ppm, based
on the total amount of the glacial acrylic acid composition.
[0164] In one embodiment, the bio-based content of the glacial
acrylic acid is greater than about 3%. In another embodiment, the
bio-based content of the glacial acrylic acid is greater than 30%.
In yet another embodiment, the bio-based content of the glacial
acrylic acid is greater than about 90%. In one embodiment, the
bio-based content of the crude acrylic acid is greater than about
3%. In another embodiment, the bio-based content of the crude
acrylic acid is greater than 30%. In yet another embodiment, the
bio-based content of the crude acrylic acid is greater than about
90%.
[0165] The glacial or crude acrylic acid composition can be made
from an aqueous solution of acrylic acid produced from renewable
resources or materials and fed into the purification process to
produce crude acrylic acid or glacial acrylic acid. Non-limiting
examples of renewable resources or materials for the production of
the aqueous solution of acrylic acid are hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof; glycerin;
carbon monoxide and ethylene oxide; carbon dioxide and ethylene;
and crotonic acid. In one embodiment, the renewable resources or
materials are hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof. In another embodiment, the
renewable resources or materials are lactic acid, lactic acid
derivatives, or mixtures thereof. In yet another embodiment, the
renewable resource or material is lactic acid.
[0166] In one embodiment, the aqueous solution of acrylic acid
comprises: 1) acrylic acid; 2) lactic acid, lactic acid
derivatives, or mixtures thereof, and is essentially free of maleic
anhydride, furfural, and formic acid. In another embodiment, the
aqueous solution of acrylic acid has from about 4 wt % to about 80
wt % acrylic acid. In another embodiment, the aqueous solution of
acrylic acid has from about 4 wt % to about 40 wt % acrylic acid.
In yet another embodiment, the aqueous solution of acrylic acid has
from about 5 wt % to about 25 wt % acrylic acid. In another
embodiment, the aqueous solution of acrylic acid has from about 8
wt % to about 16 wt % acrylic acid.
[0167] In one embodiment, the aqueous solution of acrylic acid has
from about 0.001 wt % to about 50 wt % lactic acid, lactic acid
derivatives, or mixtures thereof. In another embodiment, the
aqueous solution of acrylic acid has from about 0.001 wt % to about
20 wt % % lactic acid, lactic acid derivatives, or mixtures
thereof. In yet another embodiment, the aqueous solution of acrylic
acid has about 6 wt % % lactic acid, lactic acid derivatives, or
mixtures thereof.
[0168] In one embodiment, the aqueous solution of acrylic acid has
from about 8 wt % to about 16 wt % acrylic acid and from about 0.1
wt % to about 10 wt % lactic acid, lactic acid derivatives, or
mixtures thereof, and wherein the aqueous solution of acrylic acid
is essentially free of maleic anhydride, furfural, and formic acid.
Non-limiting examples of impurities that can be present in the
aqueous solution of acrylic acid are acetaldehyde, acetic acid, and
propanoic acid.
[0169] The aqueous solution of acrylic acid can be extracted with a
solvent to produce an extract. In one embodiment, the solvent is
selected from the group consisting of ethyl acetate, isobutyl
acetate, methyl acetate, toluene, dimethyl phthalate, hexane,
pentane, diphenyl ether, ethyl hexanoic acid, N-methylpyrrolidone,
C6 to C10 paraffin fractions, and mixtures thereof. In another
embodiment, the extraction solvent is ethyl acetate. In one
embodiment, the extraction solvent can form an azeotrope with
water.
[0170] In one embodiment, the solvent comprises at least one
polymerization inhibitor. Non-limiting examples of polymerization
inhibitors are phenothiazine and 4-methoxy phenol. In another
embodiment, the glacial acrylic acid comprises from about 200 ppm
to about 400 ppm 4-methoxyphenol. In another embodiment, the
polymerization inhibitor is added to the aqueous solution of
acrylic acid before the extracting step.
[0171] After the extraction, the extract can be dried to produce a
dried extract. The drying can be achieved with a variety of
methods, such as, and not by way of limitation, distillation and
sorption. In one embodiment, the drying is performed by azeotropic
distillation. In another embodiment, the sorption is performed on a
solid powder. In yet another embodiment, the solid powder is
selected from the group consisting of magnesium sulfate, sodium
sulfate, calcium sulfate, molecular sieves, metal hydrides,
reactive metals, and mixtures thereof. In yet another embodiment,
the sorption is performed with sodium sulfate and is followed by
filtration to produce a dried filtrate.
[0172] The dried extract or dried filtrate can be further processed
by distillation to produce a distilled acrylic acid composition. In
one embodiment, the distillation is vacuum distillation at about 70
mm Hg and about 40.degree. C. to produce a distilled crude acrylic
acid composition, and is followed by a fractional distillation at
about 40 mm Hg and collecting fractions from 59.degree. C. to
62.degree. C. to produce the distilled acrylic acid
composition.
[0173] In one embodiment, cooling of the distilled acrylic acid
composition to a temperature from about -21.degree. C. to about
14.degree. C. produces crystals of acrylic acid; partially melting
the crystals of acrylic acid produces a liquid/solid mixture;
decanting the liquid/solid mixture produces a purified acrylic acid
solid composition; fully melting the purified acrylic acid solid
composition produces a purified acrylic acid liquid composition;
and determining acrylic acid purity of the purified acrylic acid
liquid composition, and if the purity is less than about 98 wt %
acrylic acid, repeating the cooling, partially melting, decanting,
and fully melting steps on the purified acrylic acid liquid
composition until a purity of about 98 wt % acrylic acid is
achieved and a glacial acrylic acid composition is produced.
[0174] In another embodiment, cooling of the distilled acrylic acid
composition to a temperature from about -21.degree. C. to about
14.degree. C. produces crystals of acrylic acid; partially melting
the crystals of acrylic acid produces a liquid/solid mixture;
decanting the liquid/solid mixture produces a purified acrylic acid
solid composition; fully melting the purified acrylic acid solid
composition produces a purified acrylic acid liquid composition;
and determining acrylic acid purity of the purified acrylic acid
liquid composition, and if the purity is less than about 94 wt %
acrylic acid, repeating the cooling, partially melting, decanting,
and fully melting steps on the purified acrylic acid liquid
composition until a purity of about 94 wt % acrylic acid is
achieved and a crude acrylic acid composition is produced.
[0175] In yet another embodiment, cooling of the distilled acrylic
acid composition to a temperature from about -21.degree. C. to
about 14.degree. C. produces crystals of acrylic acid; partially
melting the crystals of acrylic acid produces a liquid/solid
mixture; decanting the liquid/solid mixture produces a purified
acrylic acid solid composition; fully melting the purified acrylic
acid solid composition produces a purified acrylic acid liquid
composition; and determining acrylic acid purity of the purified
acrylic acid liquid composition, and if the purity is less than
about 99 wt % acrylic acid, repeating the cooling, partially
melting, decanting, and fully melting steps on the purified acrylic
acid liquid composition until a purity of about 99 wt % acrylic
acid is achieved and a glacial acrylic acid composition is
produced.
[0176] In one embodiment, the distilling step is followed by
determining the acrylic acid purity of the distilled acrylic acid
composition, and if the purity is less than about 98 wt % acrylic
acid, repeating the distilling step on the purified acrylic acid
composition until a purity of about 98 wt % acrylic acid is
achieved and a glacial acrylic acid composition is produced. In
another embodiment, the distilling step is followed by determining
the acrylic acid purity of the distilled acrylic acid composition,
and if the purity is less than about 94 wt % acrylic acid,
repeating the distilling step on the purified acrylic acid
composition until a purity of about 94 wt % acrylic acid is
achieved and a crude acrylic acid composition is produced.
[0177] In one embodiment, the distilled acrylic acid composition is
cooled to a temperature from about 0.degree. C. to about 5.degree.
C. to produce crystals of acrylic acid.
[0178] In one embodiment of the present invention, the glacial
acrylic acid composition is produced by the steps comprising: a)
providing an aqueous solution of acrylic acid comprising 1) acrylic
acid and 2) lactic acid, lactic acid derivatives, or mixtures
thereof, and wherein the aqueous solution of acrylic acid is
essentially free of maleic anhydride, furfural, and formic acid; b)
extracting the aqueous solution of acrylic acid with a solvent to
produce an extract; c) drying the extract to produce a dried
extract; d) distilling the dried extract to produce crude acrylic
acid; e) cooling the crude acrylic acid to a temperature from about
-21.degree. C. to about 14.degree. C. to produce crystals of
acrylic acid; f) partially melting the crystals of acrylic acid to
produce a liquid/solid mixture; g) decanting the liquid/solid
mixture to produce a acrylic acid solid composition; h) fully
melting the purified acrylic acid solid composition to produce a
purified acrylic acid composition; and i) determining the acrylic
acid purity of the purified acrylic acid liquid composition and if
the purity is less than 98 wt % acrylic acid repeating the cooling,
partially melting, decanting, and fully melting steps on the
purified acrylic acid liquid composition until a purity of about 98
wt % is achieved to produce glacial acrylic acid composition.
[0179] In another embodiment of the present invention, a glacial
acrylic acid composition is provided produced by the steps
comprising: a) providing an aqueous solution of acrylic acid
comprising: 1) acrylic acid; and 2) lactic acid, lactic acid
derivatives, or mixtures thereof, and wherein the aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; b) extracting the aqueous solution of acrylic acid
with a solvent to produce an extract; c) drying the extract to
produce a dried extract; d) distilling the dried extract to produce
a distilled acrylic acid composition; and e) determining the
acrylic acid purity of the distilled acrylic acid composition, and
if the purity is less than about 98 wt % acrylic acid, repeating
the distilling step on the purified acrylic acid composition until
a purity of about 98 wt % acrylic acid is achieved and the glacial
acrylic acid composition is produced.
[0180] In one embodiment of the present invention, a crude acrylic
acid composition is provided produced by the steps comprising: a)
providing an aqueous solution of acrylic acid comprising: 1)
acrylic acid; and 2) lactic acid, lactic acid derivatives, or
mixtures thereof, and wherein the aqueous solution of acrylic acid
is essentially free of maleic anhydride, furfural, and formic acid;
b) extracting the aqueous solution of acrylic acid with a solvent
to produce an extract; c) drying the extract to produce a dried
extract; d) distilling the dried extract to produce a distilled
acrylic acid composition; and e) determining the acrylic acid
purity of the distilled acrylic acid composition, and if the purity
is less than about 94 wt % acrylic acid, repeating the distilling
step on the purified acrylic acid composition until a purity of
about 94 wt % acrylic acid is achieved and the crude acrylic acid
composition is produced.
[0181] In another embodiment of the present invention, a crude
acrylic acid composition is provided produced by the steps
comprising: a) providing an aqueous solution of acrylic acid
comprising: 1) acrylic acid; and 2) lactic acid, lactic acid
derivatives, or mixtures thereof, and wherein the aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; b) extracting the aqueous solution of acrylic acid
with a solvent to produce an extract; c) drying the extract to
produce a dried extract; d) distilling the dried extract to produce
a distilled acrylic acid composition; e) cooling the distilled
acrylic acid composition to a temperature from about -21.degree. C.
to about 14.degree. C. to produce crystals of acrylic acid; f)
partially melting the crystals of acrylic acid to produce a
liquid/solid mixture; g) decanting the liquid/solid mixture to
produce a purified acrylic acid solid composition; h) fully melting
the purified acrylic acid solid composition to produce a purified
acrylic acid liquid composition; and i) determining the acrylic
acid purity of the purified acrylic acid liquid composition, and if
the purity is less than about 94 wt % acrylic acid, repeating the
cooling, partially melting, decanting, and fully melting steps on
the purified acrylic acid liquid composition until a purity of
about 94 wt % acrylic acid is achieved and the crude acrylic acid
composition is produced.
[0182] In one embodiment of the present invention, a glacial
acrylic acid composition is provided comprising about 99 wt %
acrylic acid, produced by the steps comprising: a) providing an
aqueous solution of acrylic acid comprising: 1) from about 8 wt %
to about 16 wt % acrylic acid; and 2) from about 0.1 wt % to about
10 wt % lactic acid, lactic acid derivatives, or mixtures thereof,
and wherein the aqueous solution of acrylic acid is essentially
free of maleic anhydride, furfural, and formic acid; b) extracting
the aqueous solution of acrylic acid, with ethyl acetate to produce
an extract; c) drying the extract with sodium sulfate to produce a
dried extract; d) vacuum distilling the dried extract at about 70
mm Hg and 40.degree. C. to produce a distilled crude acrylic acid
composition; e) fractionally distilling the distilled crude acrylic
acid composition at about 40 mm Hg and collecting fractions from
59.degree. C. to 62.degree. C. to produce a distilled acrylic acid
composition; f) cooling the distilled acrylic acid composition to a
temperature from about 0.degree. C. to about 5.degree. C. to
produce crystals of acrylic acid; g) partially melting the crystals
of acrylic acid to produce a liquid/solid mixture; h) decanting the
liquid/solid mixture to produce a purified acrylic acid solid
composition; i) fully melting the purified acrylic acid composition
to produce a purified acrylic acid liquid composition; and j)
determining the acrylic acid purity of the purified acrylic acid
liquid composition, and if the purity is less than about 99 wt %
acrylic acid, repeating the cooling, partially melting, decanting,
and fully melting steps on the purified acrylic acid liquid
composition until a purity of about 99 wt % acrylic acid is
achieved and the glacial acrylic acid composition is produced.
VII Examples
[0183] The following examples are provided to illustrate the
invention, but are not intended to limit 10 the scope thereof.
Example 1
[0184] Solid dibasic potassium phosphate, K.sub.2HPO.sub.4 (36.40
g, 209 mmol, .gtoreq.98%; Sigma-Aldrich Co., St. Louis, Mo.;
catalog #P3786) was mixed quickly with an aqueous solution of
barium nitrate, Ba(NO.sub.3).sub.2 (2050 mL of a 0.08 g/mL stock
solution, 627 mmol, 99.999%; Sigma-Aldrich Co., St. Louis, Mo.;
catalog #202754) at room temperature. Phosphoric acid,
H.sub.3PO.sub.4 (58.7 mL of an 85 wt %, density=1.684 g/mL, 857
mmol; Acros Organics, Geel, Belgium; catalog #295700010), was added
to the slurry, providing a solution containing potassium (K.sup.+,
M.sup.I) and barium (Ba.sup.2+, M.sup.II) cations. The final pH of
the suspension was about 1.6. The acid-containing suspension was
then dried slowly in a glass beaker at 80.degree. C. using a
heating plate while magnetically stirring the suspension until the
liquid was evaporated and the material was almost completely dried.
Heating was continued in a oven with air circulation (G1530A,
HP6890 GC; Agilent Corp., Santa Clara, Calif.) at 50.degree. C. for
5.3 h, then at 80.degree. C. for 10 h (0.5.degree. C./min ramp),
following by cooling down at 25.degree. C. The material was
calcined at 120.degree. C. for 2 hours (0.5.degree. C./min ramp)
followed by 450.degree. C. for 4 hours (2.degree. C./min ramp)
using the same oven. After calcination, the material was left
inside the oven until it cooled down by itself at a temperature
below 25.degree. C. before it was taken out of the oven. Finally,
the catalyst was ground and sieved to about 100 .mu.m to about 200
.mu.m.
Example 2
[0185] 454 g of an 88 wt % L-lactic acid solution (Purac Corp.,
Lincolnshire, Ill.) was diluted with 1,300 g of water. The diluted
solution was heated to 95.degree. C. and held at that temperature
with stirring for about 4 to 12 hours. Then, the solution was
cooled to room temperature, and its lactic acid and lactic acid
oligomers concentrations were measured by HPLC (Agilent 1100
system; Santa Clara, Calif.) equipped with a DAD detector and a
Waters Atlantis T3 column (Catalog #186003748; Milford, Mass.)
using methods generally known by those having ordinary skill in the
art. The solution was essentially free of oligomers. Finally, the
solution was further diluted with water to yield a 20 wt % L-lactic
acid aqueous solution and essentially free of oligomers.
Example 3
[0186] The reactor consisted of an electric clam shell furnace
(Applied Test systems, Butler, Pa.) with an 8'' (20.3 cm) heated
zone with one temperature controller connected in series to another
electric clam shell furnace (Applied Test Systems, Butler, Pa.)
with a 16'' (40.6 cm) heated zone containing two temperature
controllers and a reactor tube. The reactor tube consisted of a
13'' (33 cm) borosilicate glass-lined tube (SGE Analytical Science
Pty Ltd., Ringwood, Australia)) and a 23'' (58.4 cm) borosilicate
glass lined tube connected in series using a Swagelok.TM. tee
fitting equipped with an internal thermocouple and having an inside
diameter of 9.5 mm. The head of the column was fitted with a 1/8''
(3.2 mm) stainless steel nitrogen feed line and a 1/16'' (1.6 mm)
fused silica lined stainless steel liquid feed supply line
connected to a HPLC pump (Smartline 100, Knauer, Berlin, Germany)
that was connected to a lactic acid feed tank. The bottom of the
reactor was connected to a Teflon-lined catch tank using 1/8'' (3.2
mm) fused silica lined stainless steel tubing and Swagelok.TM.
fittings. The reactor column was packed with a plug of glass wool,
13 g of fused quartz, 16'' (40.7 cm) with catalyst of Example 1 (47
g and 28.8 mL packed bed volume) and topped with 25 g of fused
quartz. The reactor tube was placed in an aluminum block and placed
into the reactor from above in a downward flow. The reactor was
preheated to 375.degree. C. overnight under 0.25 L/min nitrogen.
The nitrogen feed was increased to 0.85 L/min during the
experiment. The liquid feed was a 20 wt % aqueous solution of
L-lactic acid, prepared as in Example 2, and fed at 0.845 mL/min
(LHSV of 1.8 h.sup.-1; 50.7 g/h), giving a residence time of about
1 s (GHSV of 3,600 h.sup.-1) at STP conditions. The clam shell
heaters were adjusted to give an internal temperature about
350.degree. C. After flowing through the reactor, the gaseous
stream was cooled and the liquid was collected in the catch tank
for analysis by off-line HPLC using an Agilent 1100 system (Santa
Clara, Calif.) equipped with a DAD detector and a Waters Atlantis
T3 column (Catalog #186003748; Milford, Mass.) using methods
generally known by those having ordinary skill in the art. The
gaseous stream was analyzed on-line by GC using an Agilent 7890
system (Santa Clara, Calif.) equipped with a FID detector and
Varian CP-Para Bond Q column (Catalog #CP7351; Santa Clara,
Calif.). The crude reaction mixture was cooled and collected over
159 h to give 748 g acrylic acid as a crude mixture in 54% yield,
75% acrylic acid selectivity, and 69% conversion of lactic acid.
The acrylic acid yield, corrected for the losses during the
evaporating step, was 61% and its selectivity was 89%. The acrylic
acid aqueous concentration was 8.4 wt %, and that of lactic acid
was 6.3 wt %.
Example 4
[0187] The reaction mixtures from Example 3 were combined into four
batches and isolated to give an acrylic acid solution of 668.9 g of
acrylic acid in water. A stabilizer (200-400 ppm phenothiazine) was
added to each batch and the batches were extracted with ethyl
acetate several times. The combined ethyl acetate layers were dried
with sodium sulfate, treated with activated carbon, filtered over
diatomaceous earth, and washed with ethyl acetate. The filtrate was
evaporated at 40-70 mm Hg with a bath temperature of 23.degree.
C.-40.degree. C. to give bio-based acrylic acid as a pale yellow
liquid (81.4% yield). The bio-based acrylic acid was then
fractionally distilled using a 12 inch 14/20 Vigreux column. The
product was collected with head temperature of 59-62.degree. C.,
stabilized with 4-methoxy phenol, and placed in a 3-5.degree. C.
fridge overnight. The solution was removed from the fridge and
thawed slightly. The resulting liquid was decanted off and the
solids were combined. The crystallization was repeated several
times. The four batches were combined to give glacial acrylic acid
(218 g, 32.6% yield on purification). The glacial acrylic acid
composition consisted of 99.1 wt % acrylic acid, 0.1 wt % water,
0.7 wt % propanoic acid, and 0.1 wt % lactic acid.
Example 5
[0188] The cross-linker methylene bis-acrylamide (MBAA; 0.963 g,
0.006 mol) was dissolved in bio-based acrylic acid from Example 4
(150 g, 2.08 mol) by stirring in a holding beaker. The solution was
then added dropwise via a pipette while stirring to 124.9 g of 50
wt % solution of NaOH (1.56 mol) in a 1 L reactor equipped with
magnetic stirrer. The reactor was placed in an ice bath to remove
the heat released by the neutralization. A small amount of water
(10 g) was used to rinse the pipette and original bio-based acrylic
acid/MBAA holding beaker. Once the temperature of the neutralized
acrylic acid became about 20.degree. C., the reactor was removed
from the ice bath. Water was added to the reaction mixture to make
the whole weight of the mixture equal to 474 g. The reactor was
then closed and insulated (Baysilone paste for insulation of the
glass surfaces of vessel and lid, in addition to Teflon tape on the
outside where the lid met the vessel). The reaction mixture was
purged with argon for at least 20 min. The reactor was equipped
with a syringe needle to allow for pressure equilibration. The
reactor was then placed on a stir plate. 0.15 g of the initiator
V50 (2,2'-azobis(2-methylpropionamidine)dihydrochloride; Wako Pure
Chemical Industries, Ltd; Osaka, Japan) was injected in the mixture
while stirring and was allowed to homogenize for another 10 min.
Two UV lamps equipped with side mirrors were placed on both sides
of the reactor in a way to surround it as much as possible. When
the light was turned on, the temperature vs. time started being
recorded. The reaction temperature started increasing after certain
time and reached typically 40.degree. C. to 70.degree. C., after
which it starts slowly decreasing. The gellation was observed by
the decreasing rotation speed of the stir bar, which then came to a
complete stop. After the temperature started dropping steadily
below the maximum point (about 30 min after the temperature started
increasing above room temperature), the reactor was removed and
placed in a circulation oven preset at 60.degree. C. and stayed
there overnight (at least 18 hours). On the next day, the reactor
was removed from the oven and allowed to cool for one hour. The gel
was carefully removed from the reactor and wet-ground through a
steel mesh onto several Teflon-ized metal trays that were then
placed in an oven at 80.degree. C. and 10 mbar vacuum over 3 days.
The dried superabsorbent polymer was then milled in a regular
commercial mill (Retsch GmbH; Haan, Germany) and sieved through a
set of meshes to obtain the 150 .mu.m-850 .mu.m particle size
distribution cut. The so obtained superabsorbent polymer powder was
tested for cylinder retention capacity (CRC), extractables, and
absorption against pressure (AAP). The results were the same as
those obtained from the testing of petroleum-based superabsorbent
polymer, prepared under the same conditions as the bio-based
superabsorbent polymer, to within experimental error.
Example 6
[0189] The superabsorbent polymer powder of Example 5 was tested
for cylinder retention capacity (CRC), extractables, and absorption
against pressure (AAP) using the methods described the "Test and
Calculation Procedures" section below. The results are shown in
Table 1 below, along with results from the same tests on
petroleum-based SAP prepared under the same conditions as in
Example 5.
TABLE-US-00001 TABLE 1 SAP Property Bio-based SAP Petroleum-based
SAP Cylinder retention 43.3 40.2 capacity (CRC), [g/g]
Extractables, [%] 7.3 7.7 Absorption against 34.4 33.1 pressure
(AAP), [g/g]
[0190] The results showed that bio-based SAP and petroleum-based
SAP had the same properties, to within experimental error.
Example 7
[0191] The bio-based content of the superabsorbent polymer
composition of Example 4 is measured in accordance with ASTM D6866
Method B, as described in the Test and Calculation Procedures
section below, and is greater than about 90%.
VIII Test and Calculation Procedures
[0192] Extractables: the extractable fractions of the
water-absorbing superabsorbent polymer particles are measured in
accordance with INDA test method WSP 270.2, incorporated herein by
reference.
[0193] Cylinder retention capacity (CRC): it is measured in
accordance with INDA test method WSP 241.2, incorporated herein by
reference.
[0194] Absorption against pressure (AAP): it is measured in
accordance with INDA test method WSP 242.2, incorporated herein by
reference.
[0195] Residual monomer: it is measured in accordance with INDA
test method WSP 210.2, incorporated herein by reference.
[0196] The above tests and measurements should be carried out,
unless otherwise stated, at an ambient temperature of
23.+-.2.degree. C. and relative humidity of 50.+-.10%.
[0197] Bio-based content: the bio-based content of a material is
measured using the ASTM D6866 method, which allows the
determination of the bio-based content of materials using
radiocarbon analysis by accelerator mass spectrometry, liquid
scintillation counting, and isotope mass spectrometry. When
nitrogen in the atmosphere is struck by an ultraviolet light
produced neutron, it loses a proton and forms carbon that has a
molecular weight of 14, which is radioactive. This .sup.14C is
immediately oxidized into carbon dioxide, which represents a small,
but measurable fraction of atmospheric carbon. Atmospheric carbon
dioxide is cycled by green plants to make organic molecules during
the process known as photosynthesis. The cycle is completed when
the green plants or other forms of life metabolize the organic
molecules producing carbon dioxide, which causes the release of
carbon dioxide back to the atmosphere. Virtually all forms of life
on Earth depend on this green plant production of organic molecules
to produce the chemical energy that facilitates growth and
reproduction. Therefore, the .sup.14C that exists in the atmosphere
becomes part of all life forms and their biological products. These
renewably based organic molecules that biodegrade to carbon dioxide
do not contribute to global warming because no net increase of
carbon is emitted to the atmosphere. In contrast, fossil fuel-based
carbon does not have the signature radiocarbon ratio of atmospheric
carbon dioxide. See WO 2009/155086, incorporated herein by
reference.
[0198] The application of ASTM D6866 to derive a "bio-based
content" is built on the same concepts as radiocarbon dating, but
without use of the age equations. The analysis is performed by
deriving a ratio of the amount of radiocarbon (.sup.14C) in an
unknown sample to that of a modern reference standard. The ratio is
reported as a percentage with the units "pMC" (percent modern
carbon). If the material being analyzed is a mixture of present day
radiocarbon and fossil carbon (containing no radiocarbon), then the
pMC value obtained correlates directly to the amount of biomass
material present in the sample. The modern reference standard used
in radiocarbon dating is a NIST (National Institute of Standards
and Technology) standard with a known radiocarbon content
equivalent approximately to the year AD 1950. The year AD 1950 was
chosen because it represented a time prior to thermo-nuclear
weapons testing, which introduced large amounts of excess
radiocarbon into the atmosphere with each explosion (termed "bomb
carbon"). The AD 1950 reference represents 100 pMC. "Bomb carbon"
in the atmosphere reached almost twice normal levels in 1963 at the
peak of testing and prior to the treaty halting the testing. Its
distribution within the atmosphere has been approximated since its
appearance, showing values that are greater than 100 pMC for plants
and animals living since AD 1950. The distribution of bomb carbon
has gradually decreased over time, with today's value being near
107.5 pMC. As a result, a fresh biomass material, such as corn,
could result in a radiocarbon signature near 107.5 pMC.
[0199] Petroleum-based carbon does not have the signature
radiocarbon ratio of atmospheric carbon dioxide. Research has noted
that fossil fuels and petrochemicals have less than about 1 pMC,
and typically less than about 0.1 pMC, for example, less than about
0.03 pMC. However, compounds derived entirely from renewable
resources have at least about 95 percent modern carbon (pMC), they
may have at least about 99 pMC, including about 100 pMC.
[0200] Combining fossil carbon with present day carbon into a
material will result in a dilution of the present day pMC content.
By presuming that 107.5 pMC represents present day biomass
materials and 0 pMC represents petroleum derivatives, the measured
pMC value for that material will reflect the proportions of the two
component types. A material derived 100% from present day soybeans
would give a radiocarbon signature near 107.5 pMC. If that material
was diluted with 50% petroleum derivatives, it would give a
radiocarbon signature near 54 pMC.
[0201] A bio-based content result is derived by assigning 100%
equal to 107.5 pMC and 0% equal to 0 pMC. In this regard, a sample
measuring 99 pMC will give an equivalent bio-based content result
of 93%.
[0202] Assessment of the materials described herein was done in
accordance with ASTM D6866, particularly with Method B. The mean
values encompass an absolute range of 6% (plus and minus 3% on
either side of the bio-based content value) to account for
variations in end-component radiocarbon signatures. It is presumed
that all materials are present day or fossil in origin and that the
desired result is the amount of bio-component "present" in the
material, not the amount of bio-material "used" in the
manufacturing process.
[0203] Other techniques for assessing the bio-based content of
materials are described in U.S. Pat. Nos. 3,885,155, 4,427,884,
4,973,841, 5,438,194, and 5,661,299, and WO 2009/155086, each
incorporated herein by reference.
[0204] For example, acrylic acid contains three carbon atoms in its
structural unit. If acrylic acid is derived from a renewable
resource, then it theoretically has a bio-based content of 100%,
because all of the carbon atoms are derived from a renewable
resource.
[0205] The foregoing description is given for clearness of
understanding only, and no unnecessary limitations should be
understood therefrom, as modifications within the scope of the
invention may be apparent to those having ordinary skill in the
art.
[0206] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm."
[0207] Every document cited herein, including any cross referenced
or related patent or application, is hereby incorporated herein by
reference in its entirety unless expressly excluded or otherwise
limited. The citation of any document is not an admission that it
is prior art with respect to any invention disclosed or claimed
herein or that it alone, or in any combination with any other
reference or references, teaches, suggests or discloses any such
invention. Further, to the extent that any meaning or definition of
a term in this document conflicts with any meaning or definition of
the same term in a document incorporated by reference, the meaning
or definition assigned to that term in this document shall
govern.
[0208] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
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