U.S. patent application number 16/303005 was filed with the patent office on 2019-09-19 for process for the production of furfural using a water immiscible organic solvent.
The applicant listed for this patent is E I DU PONT DE NEMOURS AND COMPANY. Invention is credited to Torren Ryan Carlson, Jacob G. Dickinson, David William Drew, Paul Joseph Fagan, Francis G. Gallagher, Keith M. Hutchenson, Israbel Liberis, Kenneth Mersman, Gregg Sunshine.
Application Number | 20190284151 16/303005 |
Document ID | / |
Family ID | 59034954 |
Filed Date | 2019-09-19 |
United States Patent
Application |
20190284151 |
Kind Code |
A1 |
Carlson; Torren Ryan ; et
al. |
September 19, 2019 |
PROCESS FOR THE PRODUCTION OF FURFURAL USING A WATER IMMISCIBLE
ORGANIC SOLVENT
Abstract
The disclosure relates to an efficient process for the
production of a furan derivative from C5 and/or C6 sugars. The
process utilizes a water immiscible organic solvent system
comprising at least one alkyl phenol and at least one alkylated
naphthalene.
Inventors: |
Carlson; Torren Ryan;
(Newark, DE) ; Dickinson; Jacob G.; (Wilmington,
DE) ; Drew; David William; (Newark, DE) ;
Fagan; Paul Joseph; (Wilmington, DE) ; Gallagher;
Francis G.; (Wilmington, DE) ; Hutchenson; Keith
M.; (Lincoln University, PA) ; Liberis; Israbel;
(Pomona, NY) ; Mersman; Kenneth; (Newark, DE)
; Sunshine; Gregg; (Wilmington, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
E I DU PONT DE NEMOURS AND COMPANY |
Wilmington |
DE |
US |
|
|
Family ID: |
59034954 |
Appl. No.: |
16/303005 |
Filed: |
June 2, 2017 |
PCT Filed: |
June 2, 2017 |
PCT NO: |
PCT/US17/35626 |
371 Date: |
November 19, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62345031 |
Jun 3, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07D 307/50 20130101;
C07D 307/48 20130101 |
International
Class: |
C07D 307/50 20060101
C07D307/50 |
Claims
1. A process comprising: A) contacting an aqueous feedstock
comprising one or more C.sub.5 and/or C.sub.6 sugars with an acid
catalyst in the presence of a water-immiscible organic solvent at a
temperature in the range of from 90.degree. C. to 250.degree. C. to
form a furan derivative and a residual aqueous feedstock; B)
separating the residual aqueous feedstock from the water-immiscible
organic solvent; C) optionally, isolating the furan derivative from
the water-immiscible organic solvent; and D) optionally, removing
residual water or impurities from the water-immiscible organic
solvent; wherein the water-immiscible organic solvent comprises a
mixture of at least one alkyl phenol and at least one alkylated
naphthalene.
2. The process of claim 1, wherein the acid catalyst is a mineral
acid, a heteropolyacid, an organic acid, a solid acid catalyst,
carbon dioxide in water, or a combination thereof.
3. The process of claim 1, wherein the at least one alkyl phenol is
a compound represented by Structure (I): ##STR00005## wherein R is
a C.sub.1 to C.sub.16 alkyl group; and n is an integer from 1 to
5.
4. The process of claim 1, wherein the at least one alkylated
naphthalene is a compound represented by Structure (II):
##STR00006## wherein R.sup.1 is a C.sub.1 to C.sub.6 alkyl group;
R.sup.2 is a C.sub.1 to C.sub.6 alkyl group; x is an integer from 1
to 4; and y is an integer from 0 to 4.
5. The process of claim 1, wherein the water-immiscible organic
solvent consists essentially of at least one alkyl phenol and at
least one alkylated naphthalene.
6. The process of claim 1, wherein the furan derivative is
furfural, 5-hydroxymethyl furfural, or a combination thereof.
7. The process of claim 1, wherein the weight ratio of the at least
one alkyl phenol to the at least one alkylated naphthalene is in
the range of from 100:1 to 1:100.
8. The process of claim 1, wherein the aqueous feedstock comprises
C.sub.5 sugars.
9. The process of claim 1, wherein the aqueous feedstock comprises
C.sub.6 sugars.
10. The process of claim 1, wherein the step of C) isolating the
furan derivative from the water-immiscible organic solvent is a
distillation step.
11. The process of claim 1, wherein the step of C) isolating the
furan derivative from the water-immiscible organic solvent is a
flash evaporation step.
12. A process comprising: A) contacting an aqueous feedstock
comprising one or more C.sub.5 and/or C.sub.6 sugars with an acid
catalyst in the presence of a water-immiscible organic solvent at a
temperature in the range of from 90.degree. C. to 250.degree. C. to
form a furan derivative and a residual aqueous feedstock; B)
separating the residual aqueous feedstock from the water-immiscible
organic solvent; C) optionally, isolating the furan derivative from
the water-immiscible organic solvent; and D) optionally, removing
residual water or impurities from the water-immiscible organic
solvent; wherein the water-immiscible organic solvent comprises a
mixture of at least one alkyl phenol and at least one hydrocarbon
of carbon number 10 or higher.
13. The process of claim 12, wherein the hydrocarbon is diesel.
14. A composition comprising furfural or 5-hydroxymethyl furfural,
at least one alkyl phenol, at least one alkylated naphthalene, and
in the range of from 0 to 5% by weight of humins.
15. The composition of claim 14 consisting essentially of furfural
or 5-hydroxymethyl furfural, at least one alkyl phenol, at least
one alkylated naphthalene, and in the range of from 0 to 5% by
weight of humins.
Description
FIELD OF THE DISCLOSURE
[0001] The present disclosure is directed towards the production of
furan derivatives, especially, furfural, 5-hydroxymethylfurfural,
and furfuryl alcohol from C5 and C6 sugars.
BACKGROUND OF THE DISCLOSURE
[0002] Furfural and related compounds, such as 5-hydroxymethyl
furfural (HMF), are useful precursors and starting materials for
industrial chemicals for use as pharmaceuticals, herbicides,
stabilizers, fuels, fuel additives and polymers. The current
furfural manufacturing process utilizes various biomass, for
example, corn cobs, sugar cane bagasse, bamboo, saw dust, wood
chippings and oat hulls as a raw material feed stock.
[0003] The biomass is hydrolyzed under acidic conditions to its
monomer C5 and/or C6 sugars, such as glucose, fructose, xylose,
mannose, galactose, rhamnose, and arabinose. Xylose, which is a
pentose (a C5 sugar) is the sugar present in the largest amount. In
an aqueous acidic environment, the C5 sugars are subsequently
dehydrated to furfural.
[0004] A major difficulty with known methods for dehydration of
sugars is the formation of undesirable resinous material called
humins that not only leads to yield loss but can also lead to the
fouling of exposed reactor surfaces and negatively impact heat
transfer characteristics. The present disclosure seeks to minimize
the fouling of exposed reactor surfaces, and also provide a
relatively energy efficient method for removing the products
produced from the hydrolysis of the sugar feedstocks.
SUMMARY OF THE DISCLOSURE
[0005] Disclosed is a process comprising: [0006] A) contacting an
aqueous feedstock comprising one or more C5 and/or C6 sugars with
an acid catalyst in the presence of a water immiscible organic
solvent at a temperature in the range of from 90.degree. C. to
250.degree. C. to form a furan derivative and a residual aqueous
feedstock; [0007] B) separating the residual aqueous feedstock from
the water immiscible organic solvent; [0008] C) optionally,
isolating the furan derivative from the water immiscible organic
solvent and [0009] D) optionally, removing the residual water or
impurities from the water immiscible organic solvent; wherein the
water immiscible organic solvent comprises a mixture of at least
one alkyl phenol and at least one alkylated naphthalene.
[0010] The disclosure also relates to a composition comprising
furfural or 5-hydroxymethyl furfural, at least one alkyl phenol, at
least one alkylated naphthalene and in the range of from 0 to 5% by
weight of humins.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0011] The features and advantages of the present disclosure will
be more readily understood, by those of ordinary skill in the art
from reading the following detailed description. It is to be
appreciated that certain features of the disclosure, which are, for
clarity, described above and below in the context of separate
embodiments, may also be provided in combination in a single
element. Conversely, various features of the disclosure that are,
for brevity, described in the context of a single embodiment, may
also be provided separately or in any sub-combination. In addition,
references to the singular may also include the plural (for
example, "a" and "an" may refer to one or more) unless the context
specifically states otherwise.
[0012] The use of numerical values in the various ranges specified
in this application, unless expressly indicated otherwise, are
stated as approximations as though the minimum and maximum values
within the stated ranges were both proceeded by the word "about".
In this manner, slight variations above and below the stated ranges
can be used to achieve substantially the same results as values
within the ranges. Also, the disclosure of these ranges is intended
as a continuous range including each and every value between the
minimum and maximum values.
[0013] As used herein:
[0014] As used herein, the term "sugar" includes monosaccharides,
disaccharides, and oligosaccharides. Monosaccharides, or "simple
sugars," are aldehyde or ketone derivatives of straight-chain
polyhydroxy alcohols containing at least three carbon atoms. A
pentose is a monosaccharide having five carbon atoms; some examples
are xylose, arabinose, lyxose and ribose. A hexose is a
monosaccharide having six carbon atoms; some examples are glucose
and fructose. Disaccharide molecules (e.g., sucrose, lactose, and
maltose) consist of two covalently linked monosaccharide units. As
used herein, "oligosaccharide" molecules consist of about 3 to
about 20 covalently linked monosaccharide units.
[0015] The term "Cn sugar" includes monosaccharides having n carbon
atoms; disaccharides comprising monosaccharide units having n
carbon atoms; and oligosaccharides comprising monosaccharide units
having n carbon atoms. Thus, "C5 sugar" includes pentoses,
disaccharides comprising pentose units, and oligosaccharides
comprising pentose units.
[0016] The term "furan derivative" means furfural, 5-hydroxymethyl
furfural, furfuryl alcohol, ethers and esters of 5-hydroxymethyl
furfural or a combination thereof. In other embodiments, the furan
derivative is furfural, 5-hydroxymethyl furfural or a combination
thereof.
[0017] The term "hemicellulose" refers to a polymer comprising C5
and C6 monosaccharide units. Hemicellulose consists of short,
highly branched chains of sugars. In contrast to cellulose, which
is a polymer consisting essentially of beta-1,4-linked glucose, a
hemicellulose is a polymer of five different sugars. It contains
five-carbon sugars (usually D-xylose and L-arabinose) and
six-carbon sugars (D-galactose, D-glucose, and D-mannose,
fructose). Hemicellulose can also contain uronic acid, sugars in
which the terminal carbon's hydroxyl group has been oxidized to a
carboxylic acid, such as, D-glucuronic acid,
4-O-methyl-D-glucuronic acid, and D-galacturonic acid. The sugars
are partially acetylated. Typically, the acetyl content is 2 to 3%
by weight of the total weight of hemicellulose. Xylose is typically
the sugar monomer present in hemicellulose in the largest
amount.
[0018] The term "solid acid catalyst" refers to any solid material
containing Bronsted and/or Lewis acid sites, and which is
substantially undissolved by the reaction medium under ambient
conditions.
[0019] As used herein, the term "heteropolyacid" denotes an
oxygen-containing acid with P, As, Si, or B as a central atom which
is connected via oxygen bridges to W, Mo or V. Some examples are
phosphotungstic acid, molybdophosphoric acid.
[0020] The term "humins" refers to an amorphous byproduct that can
form during the disclosed process. The formation of humins is
believed to occur when the furan derivative contacts a C5 and/or C6
sugar in the aqueous phase forming an oligomeric/polymeric product.
The formation of humins can lead to lower yields of the desired
product and potentially foul the surfaces of the equipment used to
produce the furan derivative.
[0021] The phrase "water immiscible organic solvent" refers to a
composition comprising at least one alkylated phenol and at least
one alkyl naphthalene. In other embodiments, the water immiscible
organic solvent consists essentially of at least one alkylated
phenol and at least one alkyl naphthalene. The water immiscible
organic solvent forms a two-phase mixture with water at all
temperatures of the process, for example, 90.degree. C. to
250.degree. C. and the water content of the organic solvent at
25.degree. C. is less than 5% by weight, based on the total weight
of the water immiscible organic solvent. In other embodiments,
water is soluble in the water immiscible organic solvent at less
than 4%, or less than 3%, or less than 2%, or less than 1%, or less
than 0.5%, or less than 0.1%, wherein all percentage are weight
percentages based on the total weight of the water immiscible
organic solvent.
[0022] The disclosed process comprises: [0023] A) contacting an
aqueous feedstock comprising one or more C5 and/or C6 sugars with
an acid catalyst in the presence of a water immiscible organic
solvent at a temperature in the range of from 90.degree. C. to
250.degree. C. to form a furan derivative and a residual aqueous
feedstock; [0024] B) separating the residual aqueous feedstock from
the water immiscible organic solvent; [0025] C) optionally,
isolating the furan derivative from the water immiscible organic
solvent; and [0026] D) optionally, removing residual water from the
water immiscible organic solvent;
[0027] wherein the water immiscible organic solvent comprises a
mixture of at least one alkyl phenol and at least one alkylated
naphthalene.
[0028] Step A) or the process comprises contacting an aqueous
feedstock comprising one or more C5 and/or C6 sugars with an acid
catalyst in the presence of a water immiscible organic solvent at a
temperature in the range of from 90.degree. C. to 250.degree. C. to
form a furan derivative and a residual aqueous feedstock. The water
immiscible organic solvent comprises at least one alkyl phenol and
at least one alkylated naphthalene and forms a two phase mixture
wherein the aqueous feedstock is one phase and the organic solvent
mixture is the other phase.
[0029] The source of the aqueous feedstock comprising one or more
of C5 and/or C6 sugars can be from any lignocellulosic feedstock or
biomass. The lignocellulosic feedstock or biomass may be derived
from a single source, or can comprise a mixture derived from more
than one source; for example, biomass can comprise a mixture of
corn cobs and corn stover, or a mixture of grass, leaves, bioenergy
crops, agricultural residues, municipal solid waste, industrial
solid waste, sludge from paper manufacture, yard waste, wood and
forestry waste or a combination thereof. Specific examples of
biomass include, but are not limited to, bamboo, palm, corn grain,
corn cobs, crop residues such as corn husks, corn stover, corn
fiber, grasses, wheat, wheat straw, barley, barley straw, hay, rice
straw, switchgrass, waste paper, sugar cane bagasse, sorghum, soy,
components obtained from milling of grains, trees, branches, roots,
leaves, wood, wood chips, sawdust, shrubs and bushes, vegetables,
fruits, flowers, and animal manure or a combination thereof.
Biomass that is useful may include biomass that has a relatively
high carbohydrate value, is relatively dense, and/or is relatively
easy to collect, transport, store and/or handle. In some
embodiments, biomass that is useful includes corn cobs, wheat
straw, bamboo, palm, wood, sawdust, sugar cane bagasse or a
combination thereof.
[0030] Typically, lignocellulosic feedstock or biomass is contacted
with water in the presence of an acid to hydrolyze the material to
the C5 and/or C6 sugars. In one embodiment, an amount of water is
used which is at least equivalent to that of the lignocellulosic
feedstock on a weight basis. Typically, the use of more water
provides a more dilute solution of the sugars. However, minimizing
the amount of water used generally improves process economics by
reducing process volumes. In practical terms, the amount of water
used relative to the lignocellulosic feedstock will depend on the
moisture content of the feedstock, as well as the ability to
provide sufficient mixing, or intimate contact, for the biomass
hydrolysis to occur at a practical rate. The aqueous feedstock can
have in the range of from 0.5% by weight to about 50% by weight of
the C5 and/or C6 sugars, based on the total weight of the aqueous
feedstock. In other embodiments, the aqueous feedstock can comprise
in the range of from 1% to 40% by weight or in the range of from 1%
to about 30% by weight of the C5 and/or C6 sugars. All percentages
by weight are based on the total weight of the aqueous feedstock.
In some embodiments, the aqueous feedstock can comprise C5 sugars,
and, in other embodiments, the aqueous feedstock can comprise C6
sugars.
[0031] The aqueous feedstock is contacted with an acid catalyst.
The acid catalyst is a mineral acid, a heteropolyacid, an organic
acid, a solid acid catalyst, carbon dioxide in water or a
combination thereof. In some embodiments, the acid catalyst is a
mineral acid, for example, sulfuric acid, phosphoric acid,
hydrochloric acid, or a combination thereof. In other embodiments,
the acid catalyst is a heteropolyacid comprising phosphotungstic
acid, molybdophosphoric acid, or a combination of these. In some
embodiments, the acid catalyst is an organic acid comprising oxalic
acid, formic acid, acetic acid, an alkyl sulfonic acid, an aryl
sulfonic acid, a halogenated acetic acid, a halogenated
alkylsulfonic acid, a halogenated aryl sulfonic acid, or a
combination of these. An example of a suitable alkyl sulfonic acid
is methane sulfonic acid. An example of a suitable aryl sulfonic
acid is toluenesulfonic acid. An example of a suitable halogenated
acetic acid is trifluoroacetic acid. An example of a suitable
halogenated alkylsulfonic acid is trifluoromethane sulfonic acid.
An example of a suitable halogenated aryl sulfonic acid is
fluorobenzenesulfonic acid.
[0032] The solid acid catalyst is a solid acid having the thermal
stability required to survive reaction conditions. The solid acid
catalyst may be supported on at least one catalyst support.
Examples of suitable solid acids include without limitation the
following categories: 1) heterogeneous heteropolyacids (HPAs) and
their salts, 2) natural or synthetic clay minerals, such as those
containing alumina and/or silica (including zeolites), 3) cation
exchange resins, 4) metal oxides, 5) mixed metal oxides, 6) metal
salts such as metal sulfides, metal sulfates, metal sulfonates,
metal nitrates, metal phosphates, metal phosphonates, metal
molybdates, metal tungstates, metal borates, and 7) combinations of
any members of any of these categories. The metal components of
categories 4 to 6 may be selected from elements from Groups 1
through 12 of the Periodic Table of the Elements, as well as
aluminum, chromium, tin, titanium, and zirconium. Examples include,
without limitation, sulfated zirconia and sulfated titania. Any of
the above listed solid acid catalysts are well known in the art and
can be used. Some commercially available examples of solid acid
catalysts can include, for example, AMBERLYST.TM. and DOWEX.RTM.
available from Dow Chemicals (Midland, Mich.) (for example,
DOWEX.RTM. Monosphere M-31, AMBERLYST.TM. 15, AMBERLITE.TM. 120);
CG resins available from Resintech, Inc. (West Berlin, N.J.);
resins such as MONOPLUS.TM. S 100H available from Sybron Chemicals
Inc. (Birmingham, N.J.), NAFION.RTM. perfluorinated sulfonic acid
polymer, NAFION.RTM. Super Acid Catalyst (a bead-form strongly
acidic resin which is a copolymer of tetrafluoroethylene and
perfluoro-3,6-dioxa-4-methyl-7-octene sulfonyl fluoride, converted
to either the proton (H.sup.+), or the metal salt form) available
from DuPont Company (Wilmington, Del.).
[0033] The process further includes a water immiscible organic
solvent, wherein the organic solvent is a mixture of at least one
alkyl phenol and at least one alkylated naphthalene. The alkyl
phenol is:
##STR00001##
wherein R is a C1 to C16 alkyl group; and n is an integer from 1 to
5. The term "alkyl", includes straight-chain, branched or cyclic
alkyl such as, for example, methyl, ethyl, n-propyl, i-propyl, or
the different butyl, pentyl or hexyl isomers, including cycloalkyl.
The alkyl group can be in the ortho- (o-), meta- (m-) or para- (p-)
positions. In some embodiments, R is a C1 to C12 alkyl group and n
is 1 or 2. In still further embodiments, R is a C1 to C6 alkyl and
n is 1 or 2. Some specific embodiments include, for example,
tert-butyl phenol, sec-butyl phenol, pentyl phenol, hexyl phenol,
nonyl phenol and dodecyl phenol. In some embodiments, R is
sec-butyl or tert-butyl. In still further embodiments, n is 1 and R
is o-sec-butyl, m-sec-butyl, p-sec-butyl, o-tert-butyl,
m-tert-butyl or p-tert-butyl. Mixtures of any of the various alkyl
phenols can also be used.
[0034] The water immiscible organic solvent also comprises at least
one alkylated naphthalene. Suitable alkylated naphthalenes can
comprise:
##STR00002##
wherein R.sup.1 is C1 to C6 alkyl, R2 is C1 to C6 alkyl, x is an
integer from 1 to 4, and y is an integer from 0 to 4. Suitable
examples of an alkylated naphthalene can include for example, any
of the isomers of methyl naphthalene, dimethyl naphthalene, ethyl
naphthalene, diethyl naphthalene, methyl ethyl naphthalene, propyl
naphthalene, butyl naphthalene, pentyl naphthalene, hexyl
naphthalene, methyl propyl naphthalene, methyl butyl naphthalene,
methyl pentyl naphthalene, methyl hexyl naphthalene or a
combination thereof. In other embodiments, the alkylated
naphthalene is a mixture comprising various alkylated naphthalenes
having a molecular weight in the range of from 128 to 548 atomic
mass units. In other embodiments, the alkylated naphthalene can
have a molecular weight in the range of from 128 to 296 or from 128
to 212 or from 128 to 156 atomic mass units. In still other
embodiments, the alkylated naphthalene can be a mixture comprising
two or more alkylated naphthalenes. Suitable alkyl naphthalenes can
include, for example, AROMATIC.RTM. 200 fluid, AROMATIC.RTM. 150
fluid or AROMATIC.RTM. 150 ND fluid, all available from
Exxon-Mobil. The alkyl naphthalenes may have small percentages of
aromatic compounds other than naphthalenes. In some embodiments,
the alkyl naphthalene may have up to 10% by weight of an alkylated
benzene. In other embodiments, the alkylated naphthalene may have
less than 5% by weight or less than 2% by weight or less than 1% by
weight of alkylated benzenes. In some embodiments, the alkylated
naphthalene is free from naphthalene.
[0035] It has been found that a combination of both an alkyl phenol
and an alkylated naphthalene can provide a more efficient solvent
than either alkyl phenols or alkylated naphthalenes can provide by
themselves. Alkyl phenols are able to solvate a relatively larger
amount of water, when compared to alkylated naphthalenes, which
makes the separation of the furan derivative and recycle of the
solvent problematic. Alkylated naphthalenes on their own, provide a
very low water miscibility but a relatively lower partition
coefficient for the furan derivative, especially for furfural.
Thus, the use of alkyl naphthalenes, exclusively, as the solvent is
insufficient due to the low furfural yields obtained and the
insolubility of humins in pure alkylated naphthalenes, which can
result in reactor fouling.
[0036] The weight ratio of the at least one alkyl phenol to the at
least one alkylated naphthalene can vary in the range of from 100:1
to 1:100, wherein the weight ratio is based on the total weight of
the alkyl phenol and the alkylated naphthalene. It should be noted
that at relatively higher concentrations of the at least one
alkylated phenol, when compared to the at least one alkylated
naphthalene, and at high temperatures, for example, over
100.degree. C. or 125.degree. C. or 150.degree. C. or 175.degree.
C. or 200.degree. C., the at least one alkyl phenol may solvate
greater than 5% by weight water. For example, it has been found
that at around 200.degree. C. using 100% tert-butyl phenol and a
solvent to water ratio of 4:1, that a single phase system can be
generated, which is not preferred. Therefore, care should be taken
to use relatively lower temperatures, higher concentrations of the
at least one alkylated naphthalene or both in order to maintain two
liquid phases in the reactor. In other embodiments, the weight
ratio of the at least one alkyl phenol to the alkylated naphthalene
can be between and optionally include any of the following values:
95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90
and 5:95. In other embodiments, the weight ratio of the alkyl
phenol to alkylate naphthalene can be in the range of from 99:1 to
1:99 or from 10:90 to 90:10 or from 80:20 to 20:80 or from 70:30 to
25:75 or from 60:40 to 25:75 or from 50:50 to 25:75. In one
embodiment, the water immiscible organic solvent comprises a
combination of at least one alkyl phenol and at least one alkylated
naphthalene. The ratios are by weight, based on the total weight of
the alkylated phenol and the alkylated naphthalene. In other
embodiments, the water immiscible organic solvent consists of or
consists essentially of at least one alkyl phenol and at least one
alkylated naphthalene. As used in this context, the phrase
"consists essentially of" means that the water immiscible organic
solvent contains less than 10% by weight of compounds that are not
an alkyl phenol or an alkylated naphthalene, for example, the water
miscible organic solvent contains less than 10% by weight of
benzene or less than 10% by weight of at least one alkylated
benzene. In other embodiments, the phrase consisting essentially of
means that the water miscible organic solvent contains less than 5%
or less than 3% or less than 2% or less than 1% by weight of
compounds that are not the alkyl phenol or the alkylated
naphthalene. The percentage by weight is based on the total weight
of the water immiscible organic solvent.
[0037] The weight ratio of the aqueous feedstock to the water
immiscible organic solvent can vary in the range from 95:5 to 5:95.
In other embodiments, the ratio of the aqueous feedstock to the
water immiscible organic solvent can be between 10:1 to 1:10. In
still further embodiments, the ratio can be between 5:1 to 1:5 or
from 2:1 to 1:2, wherein the ratios are based on the total weight
of the aqueous feedstock to the weight of the water immiscible
organic solvent.
[0038] The step of contacting the aqueous feedstock with an acid
catalyst in the presence of the water immiscible organic solvent
can take place in any reactor that is suitable for biphasic
reactions. For example, the process can be carried out in a batch
mode using a batch reactor or can be carried out in a continuous
manner using any of the known reactors, for example, a Scheibel
column, a continuous stirred tank reactor or a plug flow reactor
may be utilized. In some embodiments, the contacting step occurs by
mixing the various components in a vessel.
[0039] The reactor can be operated at a variety of temperatures, in
the range of from 90.degree. C. to 250.degree. C. It has been found
that if the amount of the alkyl phenol is high when compared to the
amount of the alkylated naphthalene, and the temperature of the
reaction is above 250.degree. C., then the water immiscible organic
solvent can begin to absorb more than 5% by weight of water. In
other embodiments, the temperature of the mixture in the reactor
can be in the range of from 120.degree. C. to 225.degree. C. or
from 150.degree. C. to 200.degree. C. The step of contacting can
take place for a sufficient time to convert at least a portion of
the C5 and/or C6 sugars to the desired product. In some
embodiments, the reaction time can be in the range of from 1 minute
to 24 hours. In other embodiments, the reaction time can be in the
range of from 5 minutes to 12 hours or from 10 minutes to 8
hours.
[0040] During the contacting step, at least a portion of the C5
and/or C6 sugars are converted to one or more furan derivatives,
wherein the furan derivatives are more soluble in the water
immiscible organic solvent and therefore, as the reaction
progresses the concentration of the furan derivative in the organic
phase increases and the concentration of the C5 and/or C6 sugar in
the aqueous feedstock decreases, thereby forming a residual aqueous
feedstock having a lower concentration of the sugar than the
aqueous feedstock prior to the contacting step. The products of the
contacting step can include, for example, one or more furan
derivatives, for example furfural, 5-hydroxymethyl furfural or a
combination thereof. C5 sugars will generally form furfural while
C6 sugars will generally form 5-hydroxymethyl furfural. The furan
derivative products are more soluble in the water immiscible
organic solvent than in the aqueous phase and therefore, the water
immiscible organic solvent contains a relatively higher percentage
of the products than does the aqueous phase, which can minimize the
formation of by-products, for example, humins.
[0041] In some embodiments salts can be added to the aqueous
feedstock either before, during or after the contacting step A).
The addition of salts can help to drive the furan derivatives out
of the residual aqueous feedstock and into the water immiscible
organic solvent. Suitable salts can include for example, sodium
chloride, calcium chloride, sodium sulfate, magnesium sulfate,
sodium bromide, sodium iodide, potassium chloride, potassium
bromide, potassium iodide, or a combination thereof. The salts can
be used in an amount in the range of from 0% to 10% based on the
total weight of the aqueous feedstock. In other embodiments, the
amount of salt can be in the range of from 1% to 9% or 2% to 8%.
All percentages are based on the total weight of the aqueous
feedstock.
[0042] The step of B) separating the residual aqueous feedstock
from the water immiscible organic solvent can occur in any suitable
vessel. For example, the reactor vessel can be used as the
separation vessel by stopping the mixing and allowing the two
phases to separate. In other embodiments, a decanter can be used to
separate the residual aqueous feedstock and the water miscible
organic solvent comprising the product. The contact of C5 and/or C6
sugars with the acid catalyst produces both the desired furan
derivative and can also produce a byproduct called humins. The
separation of the humins from both the residual aqueous feedstock
and the water immiscible organic solvent comprising the furan
derivative can be accomplished during the separation stage. For
example, the humins can be removed by centrifugation, or by using a
tricanter. In another embodiment, the humins can be removed before
or after the separation of the two liquid phases by filtration.
[0043] The step of C) isolating the furan derivative from the water
immiscible organic solvent can be accomplished by any means known
in the art. In some embodiments, the step of isolating the furan
derivative from the water immiscible organic solvent is a
distillation step. It has been found that the isolation step using
a mixture of the alkyl phenol and the alkylated naphthalene
requires significantly less energy input to vaporize (i.e.,
distill) the furan derivative and residual water when compared to
using a solvent consisting of alkyl phenol. This results in a much
more efficient process. It is believed that since humins are less
soluble in the water immiscible organic solvent, when compared to
alkylated phenol, that they are easier to remove as well. In other
embodiments, the furan derivative can be separated from the water
immiscible organic solvent by precipitation, adsorption, or
chromatography.
[0044] The process further comprises an optional step D) removing
residual water or impurities from the water immiscible organic
solvent. In order to increase the overall efficiency of the
process, the water immiscible solvent can be purified to reuse in
step A). The removal step D) can be accomplished by removing any
water by distillation or removing impurities, for example, humins,
by precipitation. It has been found that the disclosed water
immiscible solvent tends to absorb less water when compared to a
solvent system consisting of alkylated phenol. Therefore, in some
embodiments, step D) may be a step of removing impurities from the
water immiscible organic solvent. The water immiscible organic
solvent may be recycled back to step A) with or without removal of
the water or impurities. Hum ins that may have formed can be
removed by filtration or centrifugation, as is known in the art. In
still further embodiments, the water immiscible organic solvent can
be distilled to provide humin-free water immiscible organic
solvent.
[0045] The water immiscible organic solvent can then be discarded
from the process or can be recycled using any methods known in the
art for reuse in step A). In some embodiments, the water immiscible
organic solvent can be added directly back into the process at step
A) or can be further purified by removing any humins that may have
accumulated in the water immiscible organic solvent. In other
embodiments, at least a portion of the accumulated humins can be
removed from the water immiscible organic solvent and then the at
least partially purified water immiscible organic solvent can be
returned to the process. In this way, the build-up of humins in the
system can be minimized. Similarly, the residual aqueous feedstock
can be discarded or can be recycled back into the process with or
without any additional purification steps.
[0046] In other embodiments, the disclosure comprises a composition
comprising furfural or 5-hydroxymethyl furfural, at least one alkyl
phenol, at least one alkylated naphthalene and in the range of from
0 to 5% by weight of humins. In still further embodiments, the
disclosure relates to compositions consisting of or consisting
essentially of furfural or 5-hydroxymethyl furfural, at least one
alkyl phenol, at least one alkylated naphthalene and in the range
of from 0 to 5% by weight of humins
[0047] Non-limiting examples of the process disclosed herein
include: [0048] 1. A process comprising: [0049] A) contacting an
aqueous feedstock comprising one or more C5 and/or C6 sugars with
an acid catalyst in the presence of a water immiscible organic
solvent at a temperature in the range of from 90.degree. C. to
250.degree. C. to form a furan derivative and a residual aqueous
feedstock; [0050] B) separating the residual aqueous feedstock from
the water immiscible organic solvent; [0051] C) optionally,
isolating the furan derivative from the water immiscible organic
solvent; and [0052] D) optionally, removing residual water or
impurities from the water immiscible organic solvent; [0053]
wherein the water immiscible organic solvent comprises a mixture of
at least one alkyl phenol and at least one alkylated naphthalene.
[0054] 2. The process of embodiment 1 wherein the acid catalyst is
a mineral acid, a heteropolyacid, an organic acid, a solid acid
catalyst, carbon dioxide in water or a combination thereof. [0055]
3. The process of any one of embodiments 1 or 2 wherein the alkyl
phenol is:
##STR00003##
[0055] wherein R is a C1 to C16 alkyl group; and n is an integer
from 1 to 5. [0056] 4. The process of any one of embodiments 1, 2
or 3 wherein the at least one alkylated naphthalene is:
##STR00004##
[0056] wherein R.sup.1 is C1 to C6 alkyl; R.sup.2 is C1 to C6
alkyl; x is an integer from 1 to 4; and y is an integer from 0 to
4. [0057] 5. The process of any one of embodiments 1, 2, 3 or 4
wherein the water immiscible solvent consists essentially of at
least one alkyl phenol and at least one alkylated naphthalene.
[0058] 6. The process of any one of embodiments 1, 2, 3, 4 or 5
wherein the furan derivative is furfural, 5-hydroxymethyl furfural
or a combination thereof. [0059] 7. The process of any one of
embodiments 1, 2, 3, 4, 5 or 6 wherein the weight ratio of the at
least one alkyl phenol to the at least one alkylated naphthalene is
in the range of from 100:1 to 1:100. [0060] 8. The process of any
one of embodiments 1, 2, 3, 4, 5, 6 or 7 wherein the aqueous
feedstock comprises C5 sugars. [0061] 9. The process of any one of
embodiments 1, 2, 3, 4, 5, 6, 7 or 8 wherein the step C) isolating
the furan derivative from the water immiscible organic solvent is a
distillation step. [0062] 10. A composition comprising furfural or
5-hydroxymethyl furfural, at least one alkyl phenol, at least one
alkylated naphthalene and in the range of from 0 to 5% by weight of
humins. [0063] 11. The composition of embodiments 10 wherein the
composition consists essentially of furfural or 5-hydroxymethyl
furfural, at least one alkyl phenol, at least one alkylated
naphthalene and in the range of from 0 to 5% by weight of
humins.
EXAMPLES
[0064] Unless otherwise specified, all the reagents are available
from the Sigma-Aldrich Chemical Co (St. Louis, Mo.) and/or Alfa
Aesar (Ward Hill, Mass.)
[0065] In the examples, the following abbreviations are used:
[0066] MN--1-methyl naphthalene
[0067] 2TBP--2-tert-butyl phenol
[0068] 2SBP--2-sec-butyl phenol
[0069] NP--p-nonyl phenol
Example A
[0070] Determination of the stability of the water immiscible
solvent at reaction temperatures.
[0071] Three organic solutions were prepared by combining
1-methylnaphthalene (MN) with the desired alkyl phenol. 1 weight
percent of tert-butylbenzene and sulfolane were added as dual
internal standards to the organic solutions (only tert-butylbenzene
was needed for quantitative analysis), making these solutions 74
weight percent 1-methylnaphthalene, 24 weight percent of the alkyl
phenol and 2 weight percent internal standard. The desired alkyl
phenols were 2-tertbutylphenol (2TBP), 2-sec-butylphenol (2SBP) and
p-nonylphenol (NP). 1 milliliter of each solution was added to 8
different metal tube reactors. To each tube reactor was added 10
microliters (1 volume percent) of an aqueous acidic solution
containing between 25 and 80 weight percent sulfuric acid.
[0072] The metal tubes were sealed and were then put into a hot oil
bath (initially set at 170.degree. C., this cooled to about
150.degree. C. upon loading it with the 24 metal tubes) sitting
atop a rotary shaker at 100 rpm. The lid to the heater/shaker was
sealed and time 0 was established when the oil heated up to
158.degree. C. The reaction temperature set point was adjusted to
and maintained at 160.degree. C. After 45 minutes, the tubes were
removed from the hot oil and were quenched on ice. The oil was
washed off with acetone and the samples were opened. The contents
were transferred to 4 milliliter vials. 50 microliters of each
reaction mixture was added to 200 microliters of tetrahydrofuran
(THF) in 2 milliliter gas chromatography vials.
[0073] Each sample was analyzed using gas chromatography (GC) under
the following conditions: Agilent DB-FFAP column (30 meter
long.times.250 micron inner diameter and 0.25 micron film
thickness), inlet temperature 225.degree. C., helium pressure 1.15
kg/cm.sup.2, column flow 1.5 milliliters/minute, total flow 211
milliliters/minute, split flow 204 milliliters/minute, split ratio
50:1, 1 microliter injection, detector temperature 250.degree. C.,
hydrogen 35 milliliters/minute, air 350 milliliters/minute, makeup
helium 35 milliliters/minute, initial oven temperature 50.degree.
C., ramp to 80.degree. C. at 10 Celsius/minute, ramp to 200.degree.
C. at 20.degree. C./minute, ramp to 250.degree. C. at 10.degree.
C./minute and hold for 3 minutes.
[0074] The 2TBP and 2SBP peaks were calibrated against the two
internal standards. The NP solution was an isomer of various alkyl
phenols, so the sum of the areas of the various peaks was taken to
represent an estimate of the total amount of p-nonylphenol. An
estimated response factor was adjusted such that it gave the proper
amount of NP using these 8 peaks in the non-heated control reaction
mixture. This value was then used for the other heated samples.
[0075] The ratio of the remaining solvent detected after heating
relative to the initial solvent before heating amount was expressed
as a percentage of initial solvent for each of the acid loadings.
This was used as a measure of solvent stability under the acidic
conditions. The results are shown in TABLE 1.
TABLE-US-00001 TABLE 1 Weight Percent of percent initial alkyl
sulfuric phenol (tert- acid in 2TBP 2SBP *NP butylbenzene Example
aqueous (milli- (milli- (milli- internal No. solution moles) moles)
moles) standard) 1 26.6% 54.410 n/a n/a 97% 2 32.3% 55.572 n/a n/a
99% 3 44.8% 53.487 n/a n/a 96% 4 56.1% 53.100 n/a n/a 95% 5 62.0%
45.693 n/a n/a 82% 6 68.1% 35.861 n/a n/a 64% 7 74.0% 31.673 n/a
n/a 57% 8 80.1% 25.554 n/a n/a 46% 9 26.6% n/a 54.939 n/a 98% 10
32.3% n/a 53.916 n/a 96% 11 44.8% n/a 53.935 n/a 96% 12 56.1% n/a
54.347 n/a 97% 13 62.0% n/a 55.502 n/a 99% 14 68.1% n/a 55.250 n/a
99% 15 74.0% n/a 52.214 n/a 93% 16 80.1% n/a 50.761 n/a 91% 17
26.6% n/a n/a 37.903 99% 18 32.3% n/a n/a 38.273 100% 19 44.8% n/a
n/a 39.386 103% 20 56.1% n/a n/a 40.464 106% 21 62.0% n/a n/a
37.948 99% 22 68.1% n/a n/a 37.382 98% 23 74.0% n/a n/a 35.791 94%
24 80.1% n/a n/a 35.288 92%
[0076] The results show that at higher acid levels, t-butyl phenol
is less stable than s-butyl phenol and p-nonylphenol.
Example B
[0077] Water Uptake in a Water Immiscible Organic Solvent
[0078] An excess of water (greater than 20 wt %) was added to the
organic solvents and the mixtures were vigorously agitated for
several minutes. The samples were allowed to sit overnight before
being separated by centrifugation at 4000 rpm for 5 min. The water
content of the organic solvent samples was then measured by adding
a known mass of the solvent sample to a Mettler Toledo DL31 Karl
Fischer Titrator. The titrator used AQUASTAR.RTM. CombiTitrant 5
titrant and HYDRANAL.RTM. Methanol Dry solvent. Samples were run in
sets of four, and the average value of the four runs is reported in
TABLE 2.
TABLE-US-00002 TABLE 2 Water in Aromatic organic Phenol hydrocarbon
Aromatic solvent Example (wt %) Phenol (wt %) hydrocarbon (wt %) 25
5 2TBP 95 MN 0.1 26 10 2TBP 90 MN 0.2 27 25 2TBP 75 MN 0.4 28 50
2TBP 50 MN 1.0 Comparative 100 2TBP 0 4.0 A Comparative 100 2TBP 0
4.2 B
[0079] The results in TABLE 2 show that the water immiscible
organic solvent of the disclosure absorbs a significantly less
amount of water than does 2-tert-butyl phenol as a solvent on its
own.
[0080] The following methods, described below, were used in the
formation of furan derivatives via batch reactors and continuous
stirred tank reactors. The contents of the reactors were analyzed
using the analytical methods described below.
[0081] Process Method A: Continuous Stirred Tank Reaction
[0082] The solvent and aqueous phases were pumped into a continuous
stirred tank reactor consisting of a pressure vessel with a nominal
volume of 100 milliliters (mL) and a working volume of
approximately 55 mL. The liquid level in the reactor was maintained
by a dip tube extending downward from the top of the reactor.
Nitrogen was continually added to the reactor headspace. The
aqueous phase contained the sugar and acid catalyst. The reactor
was agitated at 700 revolutions per minute (rpm) with a pitched
blade impeller. The reactor residence time was estimated by
dividing the total volumetric flow rate at the reaction temperature
of the liquid materials entering the reactor by the working volume
of the reactor. The reactor pressure was maintained above the
saturation pressure of water at the reaction temperature by a
diaphragm-style back pressure regulator. Reaction samples (5-15 mL)
were collected by a liquid handling device from Gilson throughout
the reaction. The average furfural yield and 5-carbon (C5) sugar
conversion at steady state are reported.
[0083] Process Method B: Batch Reaction
[0084] A 1 liter (L) pressure vessel was charged with a desired
amount organic solvent and aqueous phase. The aqueous phase was
prepared with the sugar(s) and the acid catalyst of interest. The
total mass of this charge was generally around 700 grams (g). The
pressure vessel was sealed and pressured to 4.83 bar (70 psig) with
nitrogen. The vessel contents were agitated by two pitched blade
impellers operating at 1000 rpm. The vessel was heated to
170.degree. C. and held at this temperature for at least 1 hour.
Samples were taken periodically from the vessel and analyzed.
[0085] Process Method C: Injected Batch Reaction
[0086] A 1 L pressure vessel was charged with the desired organic
solvent and approximately 102 g of water and 2.4 g sulfuric acid.
The aqueous xylose (24 wt %) and arabinose (16 wt %) solution was
added to a piston pump. The pressure vessel was sealed and
pressured to 4.83 bar (70 psig) with nitrogen. The vessel contents
were agitated by two pitched blade impellers operating at 1000 rpm.
The vessel was heated to 170.degree. C. When the reactor contents
reached the reaction temperature, the aqueous xylose and arabinose
solution was added to the reactor through a sample line preheated
to at least 100.degree. C. The addition of the aqueous xylose and
arabinose solution occurred in less than four minutes. The reaction
temperature was maintained for at least 30 minutes (min). Samples
were taken periodically from the vessel and analyzed.
[0087] Process Method D: Injected Batch Reaction #2
[0088] A 1 L pressure vessel was charged with the desired organic
solvent. An aqueous solution of xylose, arabinose, sulfuric acid
and succinic acid was added to a piston pump. The pressure vessel
was sealed and pressured to 4.83 bar (70 psig) with nitrogen. The
vessel contents were agitated by two pitched blade impellers
operating at 1000 rpm. The vessel was heated to 170.degree. C. When
the reactor contents reached the reaction temperature, the aqueous
solution was added to the reactor through a sample line preheated
to at least 80.degree. C. The addition of the aqueous solution
occurred in less than four minutes. The reaction temperature was
maintained for at least 30 min. Samples were taken periodically
from the vessel and analyzed.
[0089] Analytical Methods
[0090] Analytical Method E
[0091] Solvent Analysis
[0092] Biphasic samples of reaction mixtures were separated and
filtered. 200 microliters of the filtered organic layer and 200
microliters of internal standard solution consisting of 2 weight
percent dioxane in 1-methylnaphthalene were weighed into a GC vial.
The sample was thoroughly mixed and analyzed on the GC for furfural
content.
[0093] An Agilent 6890 GC was used for the analysis with the
following parameters: Agilent DB-FFAP column (30 meter
long.times.250 micron inner diameter and 0.25 micron film
thickness), inlet temperature 225 Celsius, helium pressure 16.4
pounds per square inch, column flow 1.5 milliliters/minute, total
flow 211 milliliters/minute, split flow 204 milliliters/minute,
split ratio 50:1, 1 microliter injection, detector temperature
250.degree. C., hydrogen 35 milliliters/minute, air 350
milliliters/minute, makeup helium 35 milliliters/minute, initial
oven temperature 60.degree. C., ramp to 140.degree. C. at
10.degree. C./minute, ramp to 250.degree. C. at 25.degree.
C./minute and hold for 3 minutes. The total run time was about 15.4
min. Resulting chromatograms were integrated and the raw areas, in
combination with the known amount of internal standard, were used
for quantitation.
[0094] Aqueous Layer
[0095] 100 microliters of the filtered aqueous layer was weighed
into a syringeless filter device (Whatman, UN203NPUORG) with 0.45
micron PTFE membrane. To the device was weighed 200 microliters of
aqueous internal standard solution consisting of 1 weight percent
dimethylsulfoxide. The two liquids were thoroughly mixed and then
approximately 20 mg of CaCO3 was added to the device to neutralize
the acid aqueous phase. After neutralization and evolution of gas
was completed, the filter insert was engaged and the filtered
sample was analyzed by High Performance Liquid Chromatography
(HPLC).
[0096] An Agilent 1100 series HPLC equipped with degasser, binary
pump, autosampler, column heater and refractive index detector
modules was used to analyze furfural and other compounds related to
the production of furfural. The column used was a Bio-Rad Aminex
HPX-87P 300 mm.times.7.8 mm column (Catalog No. 125-0098). To
protect this column, the sample first passed through a cation and
anion combo deashing guard column (Catalog No. 125-0118) in a
stainless steel column holder (Catalog No. 125-0139) and then
through a 30 mm.times.4.6 mm cartridge guard column (Catalog No.
125-0119) held in a stainless steel guard column holder (Catalog
No. 125-0131). The cartridge guard column and the primary column
were heated to 80.degree. C., but the deashing column remained at
room temperature. The refractive index detector used positive
polarity and was heated as close to the column temperature as
possible, which was 55.degree. C. Pure 18.2 MO Millipore DI water
was used as the mobile phase. The water was pumped through the
column at 0.6 ml/min. A 20 microliter injection of each analytical
sample was initiated for the 60 min run. Resulting chromatograms
were integrated and the raw areas, in combination with the known
amount of internal standard, were used for quantitation.
[0097] Controls
[0098] For each analysis, aqueous and organic control samples with
known concentrations of sugars and furfural, respectively, were
prepared according to the methods described previously.
[0099] Quantitation
[0100] Quantitation of these compounds using either HPLC or GC was
always done by generating calibration curves for the individual
analytes such that the y axis corresponded to the area ratio of the
analyte divided by the area of the internal standard and the x axis
corresponded to the amount of analyte divided by the amount of
internal standard. The curves for each line were linear and were
fit through zero. Quantification of real or control samples was
done by dividing the ratio of the analyte peak area to the internal
standard peak area by the slope of the calibration curve for a
particular analyte and then multiplying by the amount of internal
standard known to be in solution.
[0101] Analytical Method F
[0102] For these methods, the internal standards, dodecane (0.25-1
wt %) and succinic acid (0.5-1 wt %), were added to the solvent and
aqueous phase before reaction. Post reaction, the aqueous and
solvent layers were allowed to settle, or settling was induced by
centrifugation of the samples at 4000 rpm for 3 min.
[0103] Solvent Analysis
[0104] 300 microliters of the solvent phase was added to 0.45
micrometer filter type GC vials. These samples were analyzed using
the solvent analysis technique from Method E or by using an Agilent
5890 GC with the following parameters: A DB-17 (30 m.times.0.32
mm.times.0.5 .mu.m) capillary column. An inlet temperature
25.degree. C., helium pressure 10.0 pounds per square inch (0.703
kg/cm.sup.2), column flow 2.1 milliliters/minute, septum purge flow
of 3.7 milliliters/minute, vent flow of 44 milliliters/min, and a 1
microliter sample injection. The flame ionization detector was
operated at 250.degree. C. with 35 milliliters/min of hydrogen flow
and 350 milliliters/min of air flow.
[0105] Aqueous Analysis for Furfural
[0106] The aqueous phase was analyzed for furfural by weighing 250
microliters of an internal standard solution consisting of 0.25 wt
% dioxane in 2-propanol and 50 microliter of filtered aqueous
reaction sample to a filter type GC vial. This sample was then
analyzed using the DB-17 GC method described above.
[0107] Aqueous Phase Sugar Analysis
[0108] 38 microliters of pyridine, 200 microliters of
N,O-Bis(trimethylsilyl)trifluoroacetamide, and 2 microliters of
filtered aqueous sample were added to a GC vial and sealed. These
vials were then heated to 60.degree. C. for 30 min and analyzed on
an Agilent 6890 GC with the following conditions: A Supelco Equity
1701: 30 m.times.0.25 mm.times.0.25 .mu.m column running a constant
He pressure of 19.9 psig. The split ratio was 15:1. The injector
temperature was 260.degree. C. and the injection volume was 2
microliters. The column oven temperature was started at 140.degree.
C., ramped to 210.degree. C. at 6.degree. C./min, ramped to
250.degree. C. at 20.degree. C./min, and then held for 4 min.
[0109] Quantitation
[0110] The same quantitation methods were used as Method E.
[0111] Analytical Method G: Octane Internal Standards
[0112] This method is the same as Method F, except for the
following: 200 microliters of the solvent phase and 200 microliters
of an internal standard solution, consisting of 0.65 wt % octane in
aromatic 150 fluid naphthalene depleted, were massed into a filter
type GC vial.
[0113] Analytical Method H
[0114] Post reaction, the aqueous and solvent layers were allowed
to settle or settling was induced by centrifugation of the samples
at 4000 rpm for 3 min.
[0115] Solvent Phase
[0116] The solvent phase analysis was analogous to Method F, except
hydroxymethylfurfural was the analyte of interest.
[0117] Aqueous Phase
[0118] The aqueous phase was analyzed for sugars, fructose and
hydroxymethylfurfural using an Agilent 1200 series HPLC with a
Bio-Rad Aminex HPX-87H 300.times.7.8 millimeter column. The mobile
phase was 5 millimolar sulfuric acid in water flowing at 0.6
mL/min. The column temperature was maintained at 40.degree. C.
Samples were prepared by adding 250 microliters of sample to 900
microliters 50:50 (volume to volume) mix of acetonitrile and water
containing 1 wt % dimethyl sulfoxide. A refractive index detector
was used to detect the analytes.
[0119] Sugar Conversion and Product yields were calculated using
the following method:
Conversion ( X ) = 1 - C reactant , out C reactant , in
##EQU00001##
[0120] The conversion calculation assumes that all of the sugar
analytes are in the aqueous phase.
Yield ( Y ) = C product , out C reactant , in ##EQU00002##
[0121] Both aqueous and organic phases were analyzed for
product.
Example C
[0122] Process Method A and Analytical Method E (analytical) were
used. The residence time of the reactor was estimated to be 4.5
minutes. The aqueous phase was 9.7% by weight xylose and 1.5% by
weight arabinose. 2% by weight sulfuric acid was the catalyst, and
the water immiscible organic solvent was AROMATIC.TM. 200 aromatic
fluid with 2TBP added in various weight percentages, based on the
total amount of water immiscible organic solvent listed in TABLE
3.
TABLE-US-00003 TABLE 3 Solvent:Aq 2TBP Conversion Yield Example
ratio (wt %) (%) (%) 29 3.3 25 45 40 30 2.0 43 43 38 31 4.5 43 56
49 32 3.3 25 52 42 33 3.3 50 46 40 34 2.0 7 35 28 35 3.3 25 43 36
36 4.5 7 50 44 37 5.0 25 54 48 38 3.3 25 58 48 39 1.5 25 36 27 40
2.8 0 37 31 41 3.3 25 43 38 42 3.3 25 48 40
Example D
[0123] Process Method A and Analytical Method F were used to study
the kinetics of the biphasic process by varying the reaction
temperature, acid concentration and residence time according to
TABLE 4. The water immiscible organic phase was 25% by weight 2TBP
in AROMATIC.TM. 200 aromatic fluid or AROMATIC.TM. 200 ND aromatic
fluid. The water immiscible organic solvent was used at 3.25 grams
of solvent per gram of aqueous phase. The aqueous phase for each of
these examples contained 10% by weight xylose. The acid used was
sulfuric acid and the amount in TABLE 4 is listed as the percentage
by weight based on the aqueous phase.
TABLE-US-00004 TABLE 4 Acid Residence Temp concentration time
Conversion Yield Example (.degree. C.) (%) (minutes) (%) (%) 43 170
2.0 2.9 43 28 44 170 2.0 5.9 60 38 45 170 2.0 10.6 66 42 46 170 2.0
19.0 82 53 47 170 1.0 2.8 31 14 48 170 1.0 4.4 46 23 49 170 1.0 7.8
42 20 50 170 1.0 12.0 60 29 51 170 1.0 31.2 76 47 52 170 3.0 3.2 49
30 53 170 3.0 7.0 63 41 54 170 3.0 7.0 63 42 56 170 3.0 15.7 79 53
57 180 1.0 3.0 62 30 58 180 1.0 7.3 69 39 59 180 2.0 7.8 76 47 60
180 2.0 20.2 86 54 61 150 1.0 6.4 22 12 62 150 1.0 13.1 33 15 63
150 1.0 21.3 39 19 64 150 1.0 6.4 23 10
[0124] The results in TABLES 3 and 4 show that conversion of sugars
to furan derivatives in the presence of the water immiscible
organic solvent readily occurs over a wide range of temperatures,
acid concentrations, and residence times.
Example E
[0125] Process Method A and Analytical Method E were used to study
the conversion at higher temperatures. In these examples, the ratio
of water immiscible organic solvent to aqueous phase is 4:1
(wt/wt), the concentration of xylose in the aqueous phase is 10% by
weight and the sulfuric acid concentration is given as a percentage
by weight based on the amount of the aqueous phase. 2TBP and MN
were used as the water immiscible organic solvent.
TABLE-US-00005 TABLE 5 Residence T time wt % acid Conversion Yield
Example (.degree. C.) (minutes) phenol (%) (%) (%) Comp C 220 6.7 0
0.10 60 43 Comp D 220 6.7 0 0.07 59 41 65 200 8.9 25 0.26 35 24 66
200 8.9 25 0.19 35 23
[0126] The results in TABLE 5 show that even at relatively high
temperatures, the water immiscible organic solvent provides good
yields at low conversions.
Example F
[0127] Process method D and Analytical Methods F and G were used to
study effects of sulfuric acid, solvent to aqueous phase ratio, and
solvent composition on the conversion and yield. The alkylated
naphthalene solvent used in each case was AROMATIC.TM. solvent,
with the grade listed in TABLE 6. ND means a naphthalene depleted
grade, which contains low levels of naphthalene.
TABLE-US-00006 TABLE 6 Example 67 68 69 70 71 Phenol 2TBP 2TBP 2TBP
2TBP 2SBP amt (g) 244.0 138.1 135.2 133.2 133.2 wt % 43 25 25 25 25
Alkylated 200 200 200 ND 150 ND 200 ND naphthalene amt (g) 327.1
401.0 400.0 399.8 407.6 wt % 57 75 75 75 75 Solvent:Aqueous 4.5 3.2
3.2 3.2 3.2 ratio (g/g) Xylose (g) 27.19 33.44 33.57 33.09 33.53
Arabinose (g) 1.26 0.00 0.00 0.00 0.00 Water (g) 95.49 129.20
127.30 127.37 129.06 Sugar (wt % 22 20 20 20 20 in water) Sulfuric
acid (g) 2.56 3.34 3.39 3.31 3.35 Succinic acid (g) 1.32 1.47 1.37
1.31 1.32 Conversion 96 91 96 96 95 at maximum yield (%) Maximum 63
64 64 63 65 yield (%) Analytical F F F G F Method
Example G
[0128] Process methods C and Analytical Method E were used to study
the effect of various alkyl phenols on the conversion and
yield.
TABLE-US-00007 TABLE 7 Example 72 73 Phenol dodecyl phenol nonyl
phenol amt (g) 250.0 210.0 wt % 45 37.5 AROMATIC .TM. 200 amt (g)
310.0 350.0 wt % 55 62.5 Solvent:Aqueous ratio (g/g) 4.1 4.1 Xylose
(g) 7.80 7.80 Arabinose (g) 5.23 5.24 Water (g) 121.59 122.50 Sugar
(wt % in water) 10 10 Sulfuric acid (g) 2.41 2.42 Conversion at
maximum yield (%) 98 98 Maximum yield (%) 20 64
Example H
[0129] Process Method D and Analytical Method H were used to show
that C6 sugars could be used to form hydroxymethylfurfural.
TABLE-US-00008 TABLE 8 Example 74 Phenol 2TBP amt (g) 135.2 wt % 25
Alkylated naphthalene AROMATIC .TM. 200 ND Amt (g) 400.1 wt % 75
Solvent:Aqueous ratio (g/g) 3.3 Fructose (g) 33.55 Water (g) 127.55
Sugar (wt % in water) 20 Sulfuric acid (g) 3.38 Succinic acid (g)
1.36 Conversion at maximum yield (%) 90 Maximum yield (%) 55
Example I
[0130] Water Uptake in Organic Solvents and Modeling Data
[0131] The results of the water uptake from the Karl Fischer
Titration experiments, shown in example B, were used to determine
the water content in the organic solvent entering the distillation
column. A second-order polynomial equation provided an accurate fit
to the experimental data and allowed for interpolation between data
points.
[0132] ASPEN Calculations for Heat Duty
[0133] Modeling of the energy used for the separation of furfural
from the organic solvent was performed in ASPEN Plus v7.3 using the
RadFrac block to simulate distillation. The liquid-liquid
equilibrium was calculated using the nonrandom, two-liquid (NRTL)
model, and the vapor-liquid equilibrium was modeled using the
Peng-Robinson equation of state. The Design Institute for Physical
Properties (DIPPR) database method was used to calculate the
enthalpy. The mixture densities were calculated from the mole
fraction average of the pure component liquid molar volumes. The
modeled operating conditions of the distillation column were set to
approximate a furfural feed of 1000 kg/hr and an organic solvent
rate of 48077 kg/hr, so that 95% of the furfural was removed
overhead, the reboiler temperature was modeled at 170.degree. C.,
and the column was always run under vacuum. The phrase "calculated
heat duty" means the amount of energy required for the separation
of the furfural/water mixture and includes the energy required to
preheat the feed from 30.degree. C. to the desire preheat
temperature and the heat added in the column reboiler as determined
by the Aspen modeling. A second-order polynomial equation provided
an accurate fit to the model results and allowed for interpolation
between output points. The results are shown in Table 9.
TABLE-US-00009 TABLE 9 Amount Distillation Conditions Calculated of
water Feed Column Heat Duty 2TBP 1MN (wt %) Water Preheat Pressure
(MJ/kg Ex (wt %) (wt %) by KFT (kg/hr) (.degree. C.) (psia)
furfural) 75 5 95 0.1 47.1 140 2.2 14.3 76 10 90 0.2 76.9 -- --
14.4** 77 25 75 0.4 192 -- -- 15.2** 78 50 50 1.0 472 120 2.7 18.0
79 60 40 1.5* 703 120 2.8 19.8 80 70 30 2.0* 949 120 2.9 21.7 81 80
20 2.6* 1236 120 3.0 23.9 82 100 0 4.0 1910 80 4.0 29.6 *Estimated
from a second-order polynomial fit to the Karl Fischer titration
data. **Estimated from a second-order polynomial fit to the Aspen
calculation for heat duty.
[0134] The results from Table 9 show significantly lower calculated
heat duty for water immiscible organic solvents containing both the
alkyl phenol and the alkylated naphthalene when compared to a
solvent consisting of a pure alkyl phenol.
* * * * *