U.S. patent application number 15/689278 was filed with the patent office on 2017-12-21 for purification of bio based acrylic acid to crude and glacial acrylic acid.
The applicant listed for this patent is The Procter & Gamble Company. Invention is credited to Dimitris Ioannis Collias, Jane Ellen Godlewski, Janette Villalobos Lingoes, Juan Esteban Velasquez.
Application Number | 20170362158 15/689278 |
Document ID | / |
Family ID | 49325607 |
Filed Date | 2017-12-21 |
United States Patent
Application |
20170362158 |
Kind Code |
A1 |
Godlewski; Jane Ellen ; et
al. |
December 21, 2017 |
Purification Of Bio Based Acrylic Acid To Crude And Glacial Acrylic
Acid
Abstract
Processes for the purification of bio-based acrylic acid to
crude and glacial acrylic acid are provided. The bio-based acrylic
acid is produced from hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof. The purification includes some or
all of the following processes: extraction, drying, distillation,
and melt crystallization. The produced glacial or crude acrylic
acid contains hydroxypropionic, hydroxypropionic acid derivatives,
or mixtures thereof as an impurity.
Inventors: |
Godlewski; Jane Ellen;
(Loveland, OH) ; Lingoes; Janette Villalobos;
(Cincinnati, OH) ; Velasquez; Juan Esteban;
(Cincinnati, OH) ; Collias; Dimitris Ioannis;
(Mason, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Procter & Gamble Company |
Cincinnati |
OH |
US |
|
|
Family ID: |
49325607 |
Appl. No.: |
15/689278 |
Filed: |
August 29, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14872453 |
Oct 1, 2015 |
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15689278 |
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13760505 |
Feb 6, 2013 |
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14872453 |
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61623054 |
Apr 11, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 37/0036 20130101;
A61F 2013/530496 20130101; B01J 27/25 20130101; B01J 27/1811
20130101; B01J 27/1817 20130101; B01J 37/04 20130101; A61F 13/534
20130101; C07C 51/09 20130101; C07C 57/04 20130101; B01J 27/1853
20130101; C08F 2/10 20130101; B01J 27/187 20130101; C07C 51/377
20130101; B01J 27/195 20130101; A61F 13/53 20130101; B01J 27/1856
20130101; B01J 35/023 20130101; B01J 27/188 20130101; B01J 37/08
20130101; B01J 27/198 20130101; B01J 27/1806 20130101; A61F
2013/530489 20130101; B01J 27/186 20130101; C07C 51/48 20130101;
C07C 51/44 20130101; B01J 27/16 20130101; C07C 51/377 20130101;
C07C 57/04 20130101 |
International
Class: |
C07C 51/48 20060101
C07C051/48; C07C 57/04 20060101 C07C057/04; A61F 13/534 20060101
A61F013/534; B01J 27/16 20060101 B01J027/16; C07C 51/44 20060101
C07C051/44; C07C 51/377 20060101 C07C051/377; C07C 51/09 20060101
C07C051/09; B01J 37/08 20060101 B01J037/08; B01J 37/04 20060101
B01J037/04; B01J 37/00 20060101 B01J037/00; B01J 35/02 20060101
B01J035/02; B01J 27/25 20060101 B01J027/25; B01J 27/198 20060101
B01J027/198; B01J 27/195 20060101 B01J027/195; B01J 27/188 20060101
B01J027/188; B01J 27/187 20060101 B01J027/187; B01J 27/186 20060101
B01J027/186; B01J 27/185 20060101 B01J027/185; B01J 27/18 20060101
B01J027/18; C08F 2/10 20060101 C08F002/10 |
Claims
1. A composition of crude acrylic acid comprising between about 94
wt % and about 98 wt % acrylic acid, and wherein a portion of the
remaining impurities in said composition of crude acrylic acid is
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof.
2. The composition of claim 1, wherein the hydroxypropionic acid,
hydroxypropionic acid derivatives, or mixtures thereof is lactic
acid, lactic acid derivatives, or mixtures thereof.
3. A crude acrylic acid composition 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 said aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; b. Extracting said aqueous solution of acrylic
acid with a solvent to produce an extract; c. Drying said extract
to produce a dried extract; d. Distilling said dried extract to
produce a distilled acrylic acid composition; and e. Determining
the acrylic acid purity of said distilled acrylic acid composition,
and if the purity is less than about 94 wt % acrylic acid,
repeating said distilling step on the purified acrylic acid
composition until a purity of about 94 wt % acrylic acid is
achieved and said crude acrylic acid composition is produced.
4. The composition of claim 3, wherein the aqueous solution of
acrylic acid comprises from about 4 wt % to about 80 wt % acrylic
acid.
5. The composition of claim 3, wherein the aqueous solution of
acrylic acid comprises from about 5 wt % to about 25 wt % acrylic
acid.
6. The composition of claim 3, wherein the aqueous solution of
acrylic acid comprises from about 0.001 wt % to about 50 wt %
lactic acid, lactic acid derivatives, or mixtures thereof.
7. The composition of claim 3, wherein the aqueous solution of
acrylic acid comprises from about 0.001 wt % to about 20 wt %
lactic acid, lactic acid derivatives, or mixtures thereof.
8. The composition of claim 3, wherein said 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.
9. The composition of claim 3, wherein said drying is performed by
azeotropic distillation.
10. The composition of claim 3, wherein said drying is performed by
distillation.
11. The composition of claim 3, wherein said drying is performed by
sorption.
12. The composition of claim 11, wherein said sorption is performed
on a solid powder selected from the group consisting of magnesium
sulfate, sodium sulfate, calcium sulfate, molecular sieves, metal
hydrides, reactive metals, and mixtures thereof.
13. A crude acrylic acid composition 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 said aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; b. Extracting said aqueous solution of acrylic
acid with a solvent to produce an extract; c. Drying said extract
to produce a dried extract; d. Distilling said dried extract to
produce a distilled acrylic acid composition; e. Cooling said
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 said crystals of acrylic acid to
produce a liquid/solid mixture; g. Decanting said liquid/solid
mixture to produce a purified acrylic acid solid composition; h.
Fully melting said purified acrylic acid solid composition to
produce a purified acrylic acid liquid composition; and i.
Determining the acrylic acid purity of said purified acrylic acid
liquid composition, and if the purity is less than about 94 wt %
acrylic acid, repeating said 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 said crude acrylic acid composition is produced.
14. The composition of claim 13, wherein the aqueous solution of
acrylic acid comprises from about 4 wt % to about 80 wt % acrylic
acid.
15. The composition of claim 13, wherein the aqueous solution of
acrylic acid comprises from about 5 wt % to about 25 wt % acrylic
acid.
16. The composition of claim 13, wherein the aqueous solution of
acrylic acid comprises from about 0.001 wt % to about 50 wt %
lactic acid, lactic acid derivatives, or mixtures thereof.
17. The composition of claim 13, wherein the aqueous solution of
acrylic acid comprises from about 0.001 wt % to about 20 wt %
lactic acid, lactic acid derivatives, or mixtures thereof.
18. The composition of claim 13, wherein said 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.
19. The composition of claim 13, wherein said drying is performed
by azeotropic distillation.
20. The composition of claim 13, wherein said drying is performed
by distillation.
21. The composition of claim 13, wherein said drying is performed
by sorption.
22. The composition of claim 21, wherein said sorption is performed
on a solid powder selected from the group consisting of magnesium
sulfate, sodium sulfate, calcium sulfate, molecular sieves, metal
hydrides, reactive metals, and mixtures thereof.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to the production of
crude and glacial acrylic acid from bio-based acrylic acid produced
from hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof. More specifically, the invention relates to the
purification of bio-based acrylic acid to crude and glacial acrylic
acid using some or all of the extraction, drying, distillation, and
melt crystallization processes. The produced crude and glacial
acrylic acid contains hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof as an impurity.
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 acrylic acid is produced by the
heterogeneously-catalyzed gas-phase oxidation of propylene with the
use of molecular oxygen. Typical side products in this process are
carbonyl compounds, such as, benzaldehyde, furfurals,
propionaldehyde, etc., and acids or anhydrides, such as, formic
acid, propanoic acid, acetic acid, and maleic acid, or maleic
anhydride. The typical composition in wt % of a reaction gas coming
out of the process is (see U.S. Pat. No. 7,179,875 (issued in
2007)): acrylic acid up to 30%, steam up to 30%, carbon oxides up
to 15%, nitrogen up to 90%, oxygen up to 10%, propylene up to 1%,
acrolein up to 2%, propane up to 2%, formic acid up to 1%, acetic
acid up to 2%, propionic acid up to 2%, aldehydes up to 3%, and
maleic anhydride up to 0.5%.
[0004] Depending on the end use, there are two purity levels of
acrylic acid: crude acrylic acid (also called technical grade
acrylic acid) and glacial acrylic acid. Crude acrylic acid has a
typical minimum overall purity level of 94% and is used to make
acrylic esters for paint, adhesive, textile, paper, leather, fiber,
and plastic additive applications. Glacial acrylic acid has a
typical overall purity level ranging from 98% to 99.7% and is used
to make polyacrylic acid for superabsorbent polymer (SAP; in
disposable diapers, training pants, adult incontinence
undergarments, etc.), paper and water treatment, and detergent
co-builder applications. The levels of the impurities need to be as
low as possible in glacial acrylic acid to allow for a high-degree
of polymerization to acrylic acid polymers (PAA) and avoid adverse
effects of side products in applications. For example, aldehydes
hinder the polymerization and also lead to discoloration of the
polymerized acrylic acid; maleic anhydride forms undesirable
copolymers which have a detriment to the polymer properties; and
carboxylic acids, that do not participate in the polymerization,
might affect the final odor of PAA or SAP or provide adverse
effects in the use of the products, e.g. skin irritation when the
SAP contains formic acid, or odor when the SAP contains acetic acid
or propionic acid. To remove or reduce the amounts of side products
from petroleum-based acrylic acid and produce either
petroleum-based crude acrylic acid or petroleum-based glacial
acrylic acid, multistage distillations and/or extraction and/or
crystallizations steps were employed in the prior art (e.g. see
U.S. Pat. Nos. 5,705,688 (issued in 1998), and 6,541,665 (issued in
2003)).
[0005] Bio-based acrylic acid, produced from renewable feedstocks
or intermediate chemicals (e.g. lactic acid or lactate, glycerin,
3-hydroxypropionic acid or its ester, etc.), has different impurity
profiles and levels than petroleum-based acrylic acid. For example,
when lactic acid is used as the intermediate chemical, the major
impurities are acetaldehyde, acetic acid, lactic acid, and
propanoic acid. Nevertheless, the minimum overall purity levels of
bio-based crude acrylic acid and bio-based glacial acrylic acid
required for the final applications from bio-based acrylic acid are
expected to be the same as those in petroleum-based acrylic acid,
i.e., 94% and 98%, respectively.
[0006] Accordingly, there is a need for commercially viable
processes to purify bio-based acrylic acid produced from the
dehydration of hydroxypropionic acid, hydroxypropionic acid
derivatives, or mixtures thereof, to crude or glacial acrylic
acid.
SUMMARY OF THE INVENTION
[0007] In one embodiment of the present invention, a glacial
acrylic acid composition is provided comprising at least about 98
wt % acrylic acid, and wherein a portion of the remaining
impurities in said glacial acrylic acid composition is
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof.
[0008] In another embodiment of the present invention, a glacial
acrylic acid composition is provided produced by the steps
comprising: [0009] a. Providing an aqueous solution of acrylic acid
comprising: 1) acrylic acid; and 2) lactic acid, lactic acid
derivatives, or mixtures thereof, and wherein said aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; [0010] b. Extracting said aqueous solution of
acrylic acid, with a solvent to produce an extract; [0011] c.
Drying said extract to produce a dried extract; [0012] d.
Distilling said dried extract to produce distilled acrylic acid
composition; [0013] e. Cooling said distilled acrylic acid
composition to a temperature from about -21.degree. C. to about
14.degree. C. to produce crystals of acrylic acid; [0014] f.
Partially melting said crystals of acrylic acid to produce a
liquid/solid mixture; [0015] g. Decanting said liquid/solid mixture
to produce a purified acrylic acid solid composition; [0016] h.
Fully melting said purified acrylic acid solid composition to
produce a purified acrylic acid liquid composition; and [0017] i.
Determining the acrylic acid purity of said purified acrylic acid
liquid composition, and if the purity is less than about 98 wt %
acrylic acid, repeating said 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 said glacial acrylic acid composition is produced.
[0018] In yet another embodiment of the present invention, a
glacial acrylic acid composition is provided produced by the steps
comprising: [0019] a. Providing an aqueous solution of acrylic acid
comprising: 1) acrylic acid; and 2) lactic acid, lactic acid
derivatives, or mixtures thereof, and wherein said aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; [0020] b. Extracting said aqueous solution of
acrylic acid with a solvent to produce an extract; [0021] c. Drying
said extract to produce a dried extract; [0022] d. Distilling said
dried extract to produce a distilled acrylic acid composition; and
[0023] e. Determining the acrylic acid purity of said distilled
acrylic acid composition, and if the purity is less than about 98
wt % acrylic acid, repeating said distilling step on the purified
acrylic acid composition until a purity of about 98 wt % acrylic
acid is achieved and said glacial acrylic acid composition is
produced.
[0024] In one embodiment of the present invention, 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 said crude acrylic acid composition is
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof, is provided.
[0025] In another embodiment of the present invention, a crude
acrylic acid composition is provided produced by the steps
comprising: [0026] a. Providing an aqueous solution of acrylic acid
comprising: 1) acrylic acid; and 2) lactic acid, lactic acid
derivatives, or mixtures thereof, and wherein said aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; [0027] b. Extracting said aqueous solution of
acrylic acid with a solvent to produce an extract; [0028] c. Drying
said extract to produce a dried extract; [0029] d. Distilling said
dried extract to produce a distilled acrylic acid composition; and
[0030] e. Determining the acrylic acid purity of said distilled
acrylic acid composition, and if the purity is less than about 94
wt % acrylic acid, repeating said distilling step on the purified
acrylic acid composition until a purity of about 94 wt % acrylic
acid is achieved and said crude acrylic acid composition is
produced.
[0031] In yet another embodiment of the present invention, a crude
acrylic acid composition is provided produced by the steps
comprising: [0032] a. Providing an aqueous solution of acrylic acid
comprising: 1) acrylic acid; and 2) lactic acid, lactic acid
derivatives, or mixtures thereof, and wherein said aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; [0033] b. Extracting said aqueous solution of
acrylic acid with a solvent to produce an extract; [0034] c. Drying
said extract to produce a dried extract; [0035] d. Distilling said
dried extract to produce a distilled acrylic acid composition;
[0036] e. Cooling said distilled acrylic acid composition to a
temperature from about -21.degree. C. to about 14.degree. C. to
produce crystals of acrylic acid; [0037] f. Partially melting said
crystals of acrylic acid to produce a liquid/solid mixture; [0038]
g. Decanting said liquid/solid mixture to produce a purified
acrylic acid solid composition; [0039] h. Fully melting said
purified acrylic acid solid composition to produce a purified
acrylic acid liquid composition; and [0040] i. Determining the
acrylic acid purity of said purified acrylic acid liquid
composition, and if the purity is less than about 94 wt % acrylic
acid, repeating said 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 said
crude acrylic acid composition is produced.
[0041] 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: [0042] 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 said aqueous solution of acrylic acid is
essentially free of maleic anhydride, furfural, and formic acid;
[0043] b. Extracting said aqueous solution of acrylic acid, with
ethyl acetate to produce an extract; [0044] c. Drying said extract
with sodium sulfate to produce a dried extract; [0045] d. Vacuum
distilling said dried extract at about 70 mm Hg and 40.degree. C.
to produce a distilled crude acrylic acid composition; [0046] e.
Fractionally distilling said 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; [0047] f. Cooling said distilled acrylic acid
composition to a temperature from about 0.degree. C. to about
5.degree. C. to produce crystals of acrylic acid; [0048] g.
Partially melting said crystals of acrylic acid to produce a
liquid/solid mixture; [0049] h. Decanting said liquid/solid mixture
to produce a purified acrylic acid solid composition;
[0050] i. Fully melting said purified acrylic acid composition to
produce a purified acrylic acid liquid composition; and [0051] j.
Determining the acrylic acid purity of said purified acrylic acid
liquid composition, and if the purity is less than about 99 wt %
acrylic acid, repeating said 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 said glacial acrylic acid composition is produced.
[0052] Additional features of the invention may become apparent to
those skilled in the art from a review of the following detailed
description, taken in conjunction with the examples and the
appended claims.
DETAILED DESCRIPTION OF THE INVENTION
I Definitions
[0053] 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 %.
[0054] 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 %.
[0055] 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 %.
[0056] As used herein, the term "bio-based" material refers to a
renewable material.
[0057] As used herein, the term "renewable material" refers to a
material that is produced from a renewable resource.
[0058] 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.
[0059] 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.
[0060] 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.
[0061] 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.
[0062] As used herein, the term "cyclophosphate" refers to any
cyclic condensed phosphate constituted of two or more
corner-sharing PO.sub.4 tetrahedra.
[0063] As used herein, the term "monophosphate" or "orthophosphate"
refers to any salt whose anionic entity, [PO.sub.4].sup.3-, is
composed of four oxygen atoms arranged in an almost regular
tetrahedral array about a central phosphorus atom.
[0064] As used herein, the term "oligophosphate" refers to any
polyphosphates that contain five or less PO.sub.4 units.
[0065] 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.
[0066] 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.
[0067] As used herein, the term "cation" refers to any atom or
group of covalently-bonded atoms having a positive charge.
[0068] As used herein, the term "monovalent cation" refers to any
cation with a positive charge of +1.
[0069] As used herein, the term "polyvalent cation" refers to any
cation with a positive charge equal or greater than +2.
[0070] As used herein, the term "anion" refers to any atom or group
of covalently-bonded atoms having a negative charge.
[0071] 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.
[0072] As used herein, the term "heteropolyphosphate" refers to any
heteropolyanion, wherein X represents phosphorus (P) and Y
represents any other atom.
[0073] 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.
[0074] 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.
[0075] 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.
[0076] 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.
[0077] 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.
[0078] 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.
[0079] 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.
[0080] As used herein, the term "C2" means ethane and ethylene.
[0081] As used herein, the term "C3" means propane and
propylene.
[0082] As used herein, the term "C4" means butane and butenes.
[0083] 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.
[0084] 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.
[0085] As used herein, the term "Gas Hourly Space Velocity" or
"GHSV" in h.sup.-1 is defined as [Total gas flow rate
(mL/min)/catalyst bed volume (mL)]/60. The total gas flow rate is
calculated under Standard Temperature and Pressure conditions (STP;
0.degree. C. and 1 atm).
[0086] As used herein, the term "Liquid Hourly Space Velocity" or
"LHSV" in h.sup.-1 is defined as [Total liquid flow rate
(mL/min)/catalyst bed volume (mL)]/60.
II Purification Processes
[0087] Unexpectedly it has been found that, some or all of the
processes of extraction, drying, distilling, cooling, partial
melting, and decanting can be used to produce crude and glacial
acrylic acid produced from bio-based acrylic acid. Although the
impurities that are present in bio-based acrylic acid are different
than those present in petroleum-based acrylic acid, the same
processes that are used to purify the petroleum-based acrylic acid
can be used to purify bio-based acrylic acid to crude or glacial
purity levels.
[0088] 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.
[0089] 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.
[0090] 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.
[0091] 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.
[0092] 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.
[0093] 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%.
[0094] 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.
[0095] 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.
[0096] 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.
[0097] 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 said 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.
[0098] 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.
[0099] 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.
[0100] 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.
[0101] 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.
[0102] 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 said 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.
[0103] 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 said 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.
[0104] 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 said 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.
[0105] 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 said 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 said 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.
[0106] 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.
[0107] 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 said aqueous solution of acrylic acid is
essentially free of maleic anhydride, furfural, and formic acid; b)
extracting said aqueous solution of acrylic acid with a solvent to
produce an extract; c) drying said extract to produce a dried
extract; d) distilling said dried extract to produce crude acrylic
acid; e) cooling said 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 said crystals of acrylic acid to
produce a liquid/solid mixture; g) decanting said liquid/solid
mixture to produce a acrylic acid solid composition; h) fully
melting said purified acrylic acid solid composition to produce a
purified acrylic acid composition; and i) determining the acrylic
acid purity of said purified acrylic acid liquid composition and if
the purity is less than 98 wt % acrylic acid repeating said
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.
[0108] 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 said aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; b) extracting said aqueous solution of acrylic
acid with a solvent to produce an extract; c) drying said extract
to produce a dried extract; d) distilling said dried extract to
produce a distilled acrylic acid composition; and e) determining
the acrylic acid purity of said distilled acrylic acid composition,
and if the purity is less than about 98 wt % acrylic acid,
repeating said distilling step on the purified acrylic acid
composition until a purity of about 98 wt % acrylic acid is
achieved and said glacial acrylic acid composition is produced.
[0109] 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 said aqueous solution of acrylic acid
is essentially free of maleic anhydride, furfural, and formic acid;
b) extracting said aqueous solution of acrylic acid with a solvent
to produce an extract; c) drying said extract to produce a dried
extract; d) distilling said dried extract to produce a distilled
acrylic acid composition; and e) determining the acrylic acid
purity of said distilled acrylic acid composition, and if the
purity is less than about 94 wt % acrylic acid, repeating said
distilling step on the purified acrylic acid composition until a
purity of about 94 wt % acrylic acid is achieved and said crude
acrylic acid composition is produced.
[0110] 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 said aqueous solution
of acrylic acid is essentially free of maleic anhydride, furfural,
and formic acid; b) extracting said aqueous solution of acrylic
acid with a solvent to produce an extract; c) drying said extract
to produce a dried extract; d) distilling said dried extract to
produce a distilled acrylic acid composition; e) cooling said
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 said crystals of acrylic acid to
produce a liquid/solid mixture; g) decanting said liquid/solid
mixture to produce a purified acrylic acid solid composition; h)
fully melting said purified acrylic acid solid composition to
produce a purified acrylic acid liquid composition; and i)
determining the acrylic acid purity of said purified acrylic acid
liquid composition, and if the purity is less than about 94 wt %
acrylic acid, repeating said 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 said crude acrylic acid composition is produced.
[0111] 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 said aqueous solution of acrylic acid is essentially
free of maleic anhydride, furfural, and formic acid; b) extracting
said aqueous solution of acrylic acid, with ethyl acetate to
produce an extract; c) drying said extract with sodium sulfate to
produce a dried extract; d) vacuum distilling said dried extract at
about 70 mm Hg and 40.degree. C. to produce a distilled crude
acrylic acid composition; e) fractionally distilling said 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 said 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 said crystals of acrylic acid to produce a
liquid/solid mixture; h) decanting said liquid/solid mixture to
produce a purified acrylic acid solid composition; i) fully melting
said purified acrylic acid composition to produce a purified
acrylic acid liquid composition; and j) determining the acrylic
acid purity of said purified acrylic acid liquid composition, and
if the purity is less than about 99 wt % acrylic acid, repeating
said 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 said glacial acrylic
acid composition is produced.
III Catalysts for the Conversion of Hydroxypropionic Acid or Its
Derivatives to Acrylic Acid or Its Derivatives
[0112] In one embodiment, the catalyst comprises: (a) at least one
condensed phosphate anion selected from the group consisting of
formulae (I), (II), and (III),
[P.sub.nO.sub.3n+1].sup.(n+2)- (I)
[P.sub.nO.sub.3n].sup.n- (II)
[P.sub.(2m+n)O.sub.(5m+3n)].sup.n- (III)
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.
[0113] The anions defined by formulae (I), (II), and (III) are also
referred to as polyphosphates (or oligophosphates),
cyclophosphates, and ultraphosphates, respectively.
[0114] In another embodiment, the catalyst comprises: (a) at least
one condensed phosphate anion selected from the group consisting of
formulae (I) and (II),
[P.sub.nO.sub.3n+1].sup.(n+2)- (I)
[P.sub.nO.sub.3n].sup.n- (II)
[0115] 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.
[0116] The cations can be monovalent or polyvalent. In one
embodiment, one cation is monovalent and the other cation is
polyvalent. 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+.
[0117] 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+, Mo.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.
[0118] 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.2xP.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 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 a positive integer. In another embodiment, the catalyst
comprises any blend 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 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 a positive integer.
[0119] 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.
[0120] In one embodiment, the catalyst comprises: (a) at least two
different condensed phosphate anions selected from the group
consisting of formulae (I), (II), and (III),
[P.sub.nO.sub.3n+1].sup.(n+2)- (I)
[P.sub.nO.sub.3n].sup.n- (II)
[P.sub.(2m+n)O.sub.(5m+3n)].sup.n- (III)
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.
[0121] 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.
[0122] 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
[0123] In one embodiment, the method of preparing the catalyst
includes mixing and heating at least two different phosphorus
containing compounds, wherein each said compound is described by
one of the formulae (IV) to (XXV), or any of the hydrated forms of
said formulae:
M.sup.1.sub.y(H.sub.3-yPO.sub.4) (IV)
M.sup.II.sub.y(H.sub.3-yPO.sub.4).sub.2 (V)
M.sup.III.sub.y(H.sub.3-yPO.sub.4).sub.3 (VI)
M.sup.IV.sub.y(H.sub.3-yPO.sub.4).sub.4 (VII)
(NH.sub.4).sub.y(H.sub.3-yPO.sub.4) (VIII)
M.sup.II.sub.a(OH).sub.b(PO.sub.4).sub.c (IX)
M.sup.III.sub.d(OH).sub.e(PO.sub.4).sub.f (X)
M.sup.IIM.sup.IPO.sub.4 (XI)
M.sup.IIIM.sup.I.sub.3(PO.sub.4).sub.2 (XII)
M.sup.IV.sub.2M.sup.I(PO.sub.4).sub.3 (XIII)
M.sup.I.sub.zH.sub.4-zP.sub.2O.sub.7 (XIV)
M.sup.II.sub.vH.sub.(4-2v)P.sub.2O.sub.7 (XV)
M.sup.IVP.sub.2O.sub.7 (XVI)
(NH.sub.4).sub.zH.sub.4-zP.sub.2O.sub.7 (XVII)
M.sup.IIIM.sup.IP.sub.2O.sub.7 (XVIII)
M.sup.IH.sub.w(PO.sub.3).sub.(1+w) (XIX)
M.sup.IIH.sub.w(PO.sub.3).sub.(2+w) (XX)
M.sup.IIIH.sub.w(PO.sub.3).sub.(3+w) (XXI)
M.sup.IVH.sub.w(PO.sub.3).sub.(4+w) (XXII)
M.sup.II.sub.gM.sup.I.sub.h(PO.sub.3).sub.i (XXIII)
M.sup.III.sub.jM.sup.I.sub.k(PO.sub.3).sub.l (XXIV)
P.sub.2O.sub.5 (XXV)
wherein M.sup.I is 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 l are any positive integers, such that the equations:
2a=b+3c, 3d=e+3f, i=2g+h, and l=3j+k are satisfied.
[0124] In one embodiment, the catalyst is prepared by mixing and
heating one or more phosphorus containing compounds of formula
(IV), wherein y is equal to 1, and one or more phosphorus
containing compounds of formula (V), wherein y is equal to 2. In
another embodiment, the catalyst is prepared by mixing and heating
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 and heating 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 mixing and heating KH.sub.2PO.sub.4 and
BaHPO.sub.4.
[0125] In one embodiment, the catalyst is prepared by mixing and
heating one or more phosphorus containing compound of formula (IV),
wherein y is equal to 1, one or more phosphorus containing
compounds of formula (XV), wherein v is equal to 2. In another
embodiment, the catalyst is prepared by mixing and heating
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 and heating 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 mixing and heating
KH.sub.2PO.sub.4 and Ba.sub.2P.sub.2O.sub.7.
[0126] 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.
[0127] In another embodiment, the method of preparing the catalyst
includes mixing and heating (a) at least one phosphorus containing
compound, wherein each said compound is described by one of the
formulae (IV) to (XXV), or any of the hydrated forms of said
formulae:
M.sup.I.sub.y(H.sub.3-yPO.sub.4) (IV)
M.sup.II.sub.y(H.sub.3-yPO.sub.4).sub.2 (V)
M.sup.III.sub.y(H.sub.3-yPO.sub.4).sub.3 (VI)
M.sup.IV.sub.y(H.sub.3-yPO.sub.4).sub.4 (VII)
(NH.sub.4).sub.y(H.sub.3-yPO.sub.4) (VIII)
M.sup.II.sub.a(OH).sub.b(PO.sub.4).sub.c (IX)
M.sup.III.sub.d(OH).sub.e(PO.sub.4).sub.f (X)
M.sup.IIM.sup.IPO.sub.4 (XI)
M.sup.IIIM.sup.I.sub.3(PO.sub.4).sub.2 (XII)
M.sup.IV.sub.2M.sup.I(PO.sub.4).sub.3 (XIII)
M.sup.I.sub.zH.sub.4-zP.sub.2O.sub.7 (XIV)
M.sup.II.sub.vH.sub.(4-2v)P.sub.2O.sub.7 (XV)
M.sup.IVP.sub.2O.sub.7 (XVI)
(NH.sub.4).sub.zH.sub.4-zP.sub.2O.sub.7 (XVII)
M.sup.IIIM.sup.IP.sub.2O.sub.7 (XVIII)
M.sup.IH.sub.w(PO.sub.3).sub.(1+w) (XIX)
M.sup.IIH.sub.w(PO.sub.3).sub.(2+w) (XX)
M.sup.IIIH.sub.w(PO.sub.3).sub.(3+w) (XXI)
M.sup.IVH.sub.w(PO.sub.3).sub.(4+w) (XXII)
M.sup.II.sub.gM.sup.I.sub.h(PO.sub.3).sub.i (XXIII)
M.sup.III.sub.jM.sup.I.sub.k(PO.sub.3).sub.l (XXIV)
P.sub.2O.sub.5 (XXV)
[0128] 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 l are any positive
integers, such that the equations: 2a=b+3c, 3d=e+3f, i=2g+h, and
l=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 (XL), or any
of the hydrated forms of said formulae:
M.sup.INO.sub.3 (XXVI)
M.sup.II(NO.sub.3).sub.2 (XXVII)
M.sup.III(NO.sub.3).sub.3 (XXVIII)
M.sup.I.sub.2CO.sub.3 (XXIX)
M.sup.IICO.sub.3 (XXX)
M.sup.III.sub.2(CO.sub.3).sub.3 (XXXI)
(CH.sub.3COO)M.sup.I (XXXII)
(CH.sub.3COO).sub.2M.sup.II (XXXIII)
(CH.sub.3COO).sub.3M.sup.III (XXXIV)
(CH.sub.3COO).sub.4M.sup.IV (XXXV)
M.sup.I.sub.2O (XXXVI)
M.sup.IIO (XXXVII)
M.sup.III.sub.2O.sub.3 (XXXVIII)
M.sup.IVCO.sub.2 (XXXIX)
M.sup.ICl (XXXX)
M.sup.IICl.sub.2 (XXXXI)
M.sup.IIICl.sub.3 (XXXXII)
M.sup.IVCl.sub.4 (XXXXIII)
M.sup.I.sub.2SO.sub.4 (XXXXIV)
M.sup.IISO.sub.4 (XXXXV)
M.sup.III.sub.2(SO.sub.4).sub.3 (XXXXVI)
M.sup.IV(SO.sub.4).sub.2 (XXXXVII)
M.sup.IOH (XXXVIII)
M.sup.II(OH).sub.2 (XXXIX)
M.sup.III)OH).sub.3 (XL).
[0129] 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.
[0130] 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.
[0131] In another embodiment of the present invention, the catalyst
is prepared by mixing and heating one or more phosphorus containing
compounds of formulae (IV) to (XXV) or their hydrated forms, and
one or more nitrate salts of formulae (XXVI) to (XXVIII) 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 (IV) and one or more nitrate salts
of formula (XXVII). In a further embodiment of the present
invention, the catalyst is prepared by mixing and heating a
phosphorus containing compound of formula (IV) wherein y is equal
to 2, a phosphorus containing compound of formula (IV) wherein y is
equal to 0 (i.e., phosphoric acid), and a nitrate salt of formula
(XXVII). 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.
[0132] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (IV) and one or more nitrate salts of formula
(XXVIII). In a further embodiment of the present invention, the
catalyst is prepared by mixing and heating a phosphorus containing
compound of formula (IV) wherein y is equal to 2, a phosphorus
containing compound of formula (IV) wherein y is equal to 0 (i.e.,
phosphoric acid), and a nitrate salt of formula (XXVIII). 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.
[0133] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (V) and one or more nitrate salts of formula
(XXVI). In another embodiment of the present invention, the
catalyst is prepared by mixing and heating a phosphorus containing
compound of formula (V) wherein y is equal to 2, a phosphorus
containing compound of formula (V) wherein y is equal to 0 (i.e.,
phosphoric acid), and a nitrate salt of formula (XXVI). In yet
another embodiment of the present invention, the catalyst is
prepared by mixing and heating BaHPO4, H.sub.3PO.sub.4, and
KNO.sub.3. In another embodiment, the catalyst is prepared by
mixing and heating CaHPO.sub.4, H.sub.3PO.sub.4, and KNO.sub.3.
[0134] In one embodiment of this invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (V), one or more phosphorus containing
compounds of formula (XV), and one or more nitrate salts of formula
(XXVI). In a further embodiment of this invention, the catalyst is
prepared by mixing and heating a phosphorus containing compound of
formula (V), wherein y is equal to 0 (i.e., phosphoric acid); a
phosphorus containing compound of formula (XV), wherein v is equal
to 2; and a nitrate salt of formula (XXVI). 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.
[0135] In another embodiment of this invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (VI) and one or more nitrate salts of formula
(XXVI). In another embodiment of this invention, the catalyst is
prepared by mixing and heating a phosphorus containing compound of
formula (VI), wherein y is equal to 3; a phosphorus containing
compound of formula (VI), wherein y is equal to 0 (i.e., phosphoric
acid); and a nitrate salt of formula (XXVI). 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.
[0136] In one embodiment of this invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (IV), one or more phosphorus containing
compounds of formula (IX), and one or more nitrate salts of formula
(XXVII). In another embodiment of this invention, the catalyst is
prepared by mixing and heating a phosphorus containing compound of
formula (IV), wherein y is equal to 2; a phosphorus containing
compound of formula (IV), wherein y is equal to 0 (i.e., phosphoric
acid); a phosphorus containing compound of formula (IX), wherein a
is equal to 2, b is equal to 1, and c is equal to 1; and a nitrate
salt of formula (XXVII). 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.
[0137] In one embodiment of this invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formula (V), one or more phosphorus containing
compounds of formula (IX), and one or more nitrate salts of formula
(XXVI). In another embodiment of this invention, the catalyst is
prepared by mixing and heating a phosphorus containing compound of
formula (V), wherein y is equal to 3; a phosphorus containing
compound of formula (V), wherein y is equal to 0 (i.e., phosphoric
acid); a phosphorus containing compound of formula (IX), wherein a
is equal to 2, b is equal to 1, and c is equal to 1; and a nitrate
salt of formula (XXVI). 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.
[0138] 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 (IV) to (XXV) or any of
the hydrated forms, and one or more carbonate salts described by
one of the formulae (XXIX) to (XXXI) or any of the hydrated
forms.
[0139] 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 (IV) to (XXV) or any of
the hydrated forms, and one or more acetate salts described by one
of the formulae (XXXII) to (XXXV), any other organic acid-derived
salts, or any of the hydrated forms.
[0140] 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 (IV) to (XXV) or any of
the hydrated forms, and one or more metal oxides described by one
of the formulae (XXXVI) to (XXXIX) or any of the hydrated
forms.
[0141] 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 (IV) to (XXV) or any of
the hydrated forms, and one or more chloride salts described by one
of the formulae (XXXX) to (XXXXIII), any other halide salts, or any
of the hydrated forms.
[0142] 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 (IV) to (XXV) or any of
the hydrated forms, and one or more sulfate salts described by one
of the formulae (XXXXIV) to (XXXXVII) or any of the hydrated
forms.
[0143] 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 (IV) to (XXV) or any of
the hydrated forms, and one or more hydroxides described by one of
the formulae (XXXXVIII) to (XL) or any of the hydrated forms.
[0144] In one embodiment of the present invention, the catalyst is
prepared by mixing and heating one or more phosphorus containing
compounds of formulae (IV) to (XXV), and two or more non-phosphorus
containing compounds of formulae (XXVI) to (XL) or their hydrated
forms.
[0145] 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.
[0146] When the catalyst includes only two different cations, the
molar ratio between cations is, in one embodiment, between about
1:50 and about 50:1; and in another embodiment, the molar ratio
between cations is between about 1:4 and about 4:1. For example,
when the catalyst includes potassium (K.sup.+) and barium
(Ba.sup.2+), the molar ratio between them (K:Ba), in one
embodiment, is between about 1:4 and about 4:1. Also, when the
catalyst is prepared by mixing and heating K.sub.2HPO.sub.4,
Ba(NO.sub.3).sub.2, and H.sub.3PO.sub.4, the potassium and barium
are present, in another embodiment, in a molar ratio, K:Ba, between
about 2:3 to about 1:1.
[0147] 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.
[0148] 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.
[0149] 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.
[0150] 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.
[0151] 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.
[0152] 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.
[0153] 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.
[0154] 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.
[0155] 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.
[0156] 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.
[0157] 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.
[0158] 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, es
terific ations , 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
[0159] 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 said 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.
[0160] 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.
[0161] 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.
[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 derivative is methyl lactate. Methyl lactate
can be neat or in an aqueous solution.
[0163] 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.
[0164] 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 %.
[0165] 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.
[0166] 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.
[0167] 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.
[0168] 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,
niobate s , tantalates , selenates, arsenatophosphates ,
phosphoaluminates, phosphoborates, phosphocromates ,
phosphomolybdates, phospho silicate s , pho spho sulfates ,
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.
[0169] 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.
[0170] 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%.
[0171] 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 said hydroxypropionic acid comprises
oligomers in said 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 said acrylic acid, acrylic acid
derivatives, or mixtures thereof.
[0172] 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.
[0173] 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 said hydroxypropionic acid is in
monomeric form in said 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.
[0174] 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.-.
[0175] 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 said about 20 wt % lactic acid
aqueous solution at a temperature of about 95.degree. C. to about
100.degree. C. to remove oligomers of said lactic acid, producing a
monomeric lactic acid solution comprising at least about 95 wt % of
said lactic acid in monomeric form based on the total amount of
lactic acid; c) combining said monomeric lactic acid solution with
nitrogen to form an aqueous solution/gas blend; d) evaporating said
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 said 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 said mixture with a dehydration
catalyst under a pressure of about 360 psig, producing said acrylic
acid; and f) cooling said acrylic acid at a GHSV from about 360
h.sup.-1 to about 36,000 h.sup.-1.
[0176] 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 said hydroxypropionic
acid is in monomeric form in said aqueous solution, and wherein the
hydroxypropionic acid, hydroxypropionic acid derivatives, or
mixtures thereof comprise from about 10 wt % to about 25 wt % of
said aqueous solution; b) combining said aqueous solution with an
inert gas to form an aqueous solution/gas blend; c) evaporating
said aqueous solution/gas blend to produce a gaseous mixture; and
d) dehydrating said gaseous mixture by contacting said mixture with
a dehydration catalyst producing acrylic acid, acrylic acid
derivatives, or mixtures thereof.
[0177] 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 said alkyl
lactates or said solution comprising said alkyl lactates and said
solvent with an inert gas to form a liquid/gas blend; c)
evaporating said liquid/gas blend to produce a gaseous mixture; and
d) dehydrating said gaseous mixture by contacting said gaseous
mixture with a dehydration catalyst under a pressure of at least
about 80 psig, producing acrylic acid, acrylic acid derivatives, or
mixtures thereof.
[0178] 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.
[0179] 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 EXAMPLES
[0180] The following examples are provided to illustrate the
invention, but are not intended to limit the scope thereof.
Example 1
[0181] 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
[0182] 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
[0183] 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
[0184] 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 at 40 mm Hg using a 12 inch 14/20 Vigreux
column. The product was collected with head temperature of
59.degree. C.-62.degree. C., stabilized with 4-methoxy phenol, and
placed in a 3.degree. C.-5.degree. C. fridge overnight. The
solution was removed from the fridge and thawed. 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
[0185] The bio-based content of the glacial acrylic acid
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%.
VII Test and Calculation Procedures
[0186] 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.
[0187] 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.
[0188] 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), and
may have at least about 99 pMC, including about 100 pMC.
[0189] 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.
[0190] 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%.
[0191] 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.
[0192] Other techniques for assessing the bio-based content of
materials are described in U.S. Pat. Nos. 3,885155, 4,427,884,
4,973,841, 5,438,194, and 5,661,299, and WO 2009/155086, each
incorporated herein by reference.
[0193] 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.
[0194] 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.
[0195] 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."
[0196] 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.
[0197] 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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