U.S. patent application number 15/463890 was filed with the patent office on 2017-07-06 for process to prepare levulinic acid.
The applicant listed for this patent is GFBiochemicals Limited. Invention is credited to Cora M. Leibig, Brian D. Mullen, Dorie Janine Yontz.
Application Number | 20170190651 15/463890 |
Document ID | / |
Family ID | 50622946 |
Filed Date | 2017-07-06 |
United States Patent
Application |
20170190651 |
Kind Code |
A1 |
Mullen; Brian D. ; et
al. |
July 6, 2017 |
PROCESS TO PREPARE LEVULINIC ACID
Abstract
The invention describes processes to prepare levulinic acid,
formic acid and/or hydroxymethyl furfural from various biomass
materials.
Inventors: |
Mullen; Brian D.; (Delano,
MN) ; Yontz; Dorie Janine; (Bloomington, MN) ;
Leibig; Cora M.; (Maple Grove, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GFBiochemicals Limited |
Valletta |
|
MT |
|
|
Family ID: |
50622946 |
Appl. No.: |
15/463890 |
Filed: |
March 20, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14748278 |
Jun 24, 2015 |
9598341 |
|
|
15463890 |
|
|
|
|
13831317 |
Mar 14, 2013 |
9073841 |
|
|
14748278 |
|
|
|
|
61722766 |
Nov 5, 2012 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C 51/00 20130101;
C07C 51/47 20130101; C07C 51/00 20130101; C07C 59/185 20130101 |
International
Class: |
C07C 51/47 20060101
C07C051/47; C07C 51/00 20060101 C07C051/00 |
Claims
1. A process to prepare levulinic acid comprising the steps: a)
heating an aqueous solution of a mineral acid to a temperature from
about 60.degree. C. to about 160.degree. C. in a reactor, wherein
the mineral acid is present from at least 20 percent by to about 80
percent by weight; and b) adding from about 0.15 pounds to about 80
pounds per hour of a monosaccharide or di-saccharide per 100 pounds
of the heated aqueous acid in the reactor to form a reaction
mixture, to provide levulinic acid.
2. The process of claim 1, further comprising the step of combining
the reaction mixture comprising levulinic acid with a phenolic or
substituted phenolic extraction solvent to create an extraction
phase and an aqueous raffinate phase, wherein levulinic acid and
optionally, formic acid are in the extraction phase.
3. The process of claim 2, wherein the phenolic or substituted
phenolic extraction solvent is a phenol, an alkylphenol, a xylenol,
a methoxyphenol, a cresol, a polydimethylsiloxane, a substituted
alkyl phenol, a tertiary amine/alkyl phenol mixture, phenol/alkyl
phenol blends with a C5-C36 hydrocarbon or C6-C12 aromatic
hydrocarbons, 2-ethyl-hexanoic acid or perfluoro-octanoic acid or
perfluoro-octanol or mixtures thereof.
4. The process of claim 3, wherein the extraction solvent comprises
phenol, 4-methoxyphenol, 2-methoxyphenol, 3-methoxyphenol,
2-sec-butyl phenol, 3-sec-butyl phenol, 4-sec-butyl phenol,
2-t-butyl phenol, 4-t-butyl phenol, 2,4-di-t-butyl phenol,
2,4-di-methoxyphenol, 2-methylphenol, 3-methylphenol,
4-methylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol,
3,4-xylenol, or 3,5-xylenol, 4-hexyl-resorcinol, butylated
hydroxyl-toluene (BHT), 2,5-dimethoxyphenol, 3,5-dimethoxy phenol,
2,6-dimethoxy phenol, nonylphenol, or mixtures thereof.
5. The process of claim 2, further comprising the step of
subjecting the extraction phase to a base, an anion exchange resin,
or water washing the extraction phase to reduce the amount of
mineral acid present to less than or equal to 0.5 weight percent of
the extraction phase.
6. The process of claim 2, further comprising the step of treating
the aqueous raffinate phase with an adsorbent, such as activated
carbon or with a hydrocarbon solvent to decrease the amount of the
extraction solvent from the raffinate phase.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/748,278, filed Jun. 24, 2015, which is a continuation
of U.S. patent Ser. No. 13/831,317, filed Mar. 14, 2013, now U.S.
Pat. No. 9,073,841 issued on Jul. 7, 2015, which claims priority to
U.S. Provisional Patent Application No. 61/722,766, filed Nov. 5,
2012, all entitled "PROCESS TO PREPARE LEVULINIC ACID", the
contents of which are incorporated herein in their entirety for all
purposes.
FIELD OF THE INVENTION
[0002] The invention relates generally to the preparation and
purification of levulinic acid.
BACKGROUND OF THE INVENTION
[0003] Levulinic acid can be used to make resins, plasticizers,
specialty chemicals, herbicides and used as a flavor substance.
Levulinic acid derivatives are useful as solvents, and as a
starting materials in the preparation of a variety of industrial
and pharmaceutical compounds such as diphenolic acid (useful as a
component of protective and decorative finishes), calcium
levulinate (a form of calcium for intravenous injection used for
calcium replenishment and for treating hypocalcemia. The use of the
sodium salt of levulinic acid as a replacement for ethylene glycols
as an antifreeze has also been proposed.
[0004] Esters of levulinic acid are known to be useful as
plasticizers and solvents, and have been suggested as fuel
additives. Acid catalyzed dehydration of levulinic acid yields
alpha-angelica lactone.
[0005] Levulinic acid has been synthesized by a variety of chemical
methods. But levulinic acid has not attained much commercial
significance due in part to the low yields of levulinic acid
obtained from most synthetic methods. Yet, another reason is the
formation of a formic acid byproduct during synthesis and its
separation from the levulinic acid. Therefore, the production of
levulinic acid has had high associated equipment costs. Despite the
inherent problems in the production of levulinic acid, however, the
reactive nature of levulinic acid makes it an ideal intermediate
leading to the production of numerous useful derivatives.
[0006] Cellulose-based biomass, which is an inexpensive feedstock,
can be used as a raw material for making levulinic acid. The supply
of sugars from cellulose-containing plant biomass is immense and
replenishable. Most plants contain cellulose in their cell walls.
For example, cotton comprises 90% cellulose. Furthermore, it has
been estimated that roughly 75% of the approximate 24 million tons
of biomass generated on cultivated lands and grasslands are waste.
The cellulose derived from plant biomass can be a suitable source
of sugars to be used in the process of obtaining levulinic acid.
Thus, the conversion of such waste material into a useful chemical,
such as levulinic acid, is desirable.
BRIEF SUMMARY OF THE INVENTION
[0007] There are a few major issues in producing levulinic acid
form biomass. First, levulinic acid is difficult to separate from
the mineral acid catalysts (sulfuric acid or HCl) or the
byproducts, especially from formic acid and char. Secondly, current
processes generally require high temperature reaction conditions,
generally long digestion periods of biomass, specialized equipment
to withstand hydrolysis conditions, and as a result, the yield of
the levulinic acid is quite low, generally in yields of less than
50 stoichiometric percent or less. Also, the solids obtained under
the current reaction conditions can result in fouling of the
reactor and downstream equipment due to plugging or sticking of the
char to the internals of the equipment.
[0008] Therefore, a need exists for a new approach that overcomes
one or more of the current disadvantages noted above.
[0009] The present invention surprisingly provides novel approaches
to more efficiently prepare levulinic acid in commercial quantities
with high yields and high purities. Additionally, the production of
5-hydroxymethyl-2-furaldehyde (HMF) intermediate is also described,
which is an important intermediate to the product of levulinic
acid.
[0010] In one aspect, the use of high concentration of acid, e.g.,
about 20-80 weight percent based on the total weight of reaction
components and low reaction temperature (approximately
60-160.degree. C.) helps to improve yield of desired products with
reduction of undesired byproducts. This is one attribute, but there
are more.
[0011] While multiple embodiments are disclosed, still other
embodiments of the present invention will become apparent to those
skilled in the art from the following detailed description. As will
be apparent, the invention is capable of modifications in various
obvious aspects, all without departing from the spirit and scope of
the present invention. Accordingly, the detailed descriptions are
to be regarded as illustrative in nature and not restrictive.
DETAILED DESCRIPTION
[0012] In the specification and in the claims, the terms
"including" and "comprising" are open-ended terms and should be
interpreted to mean "including, but not limited to . . . ." These
terms encompass the more restrictive terms "consisting essentially
of" and "consisting of."
[0013] It must be noted that as used herein and in the appended
claims, the singular forms "a", "an", and "the" include plural
reference unless the context clearly dictates otherwise. As well,
the terms "a" (or "an"), "one or more" and "at least one" can be
used interchangeably herein. It is also to be noted that the terms
"comprising", "including", "characterized by" and "having" can be
used interchangeably.
[0014] Unless defined otherwise, all technical and scientific terms
used herein have the same meanings as commonly understood by one of
ordinary skill in the art to which this invention belongs. All
publications and patents specifically mentioned herein are
incorporated by reference in their entirety for all purposes
including describing and disclosing the chemicals, instruments,
statistical analyses and methodologies which are reported in the
publications which might be used in connection with the invention.
All references cited in this specification are to be taken as
indicative of the level of skill in the art. Nothing herein is to
be construed as an admission that the invention is not entitled to
antedate such disclosure by virtue of prior invention.
[0015] The present invention provides various advantages in the
preparation of levulinic acid, hydroxymethyl furfural and/or formic
acid. The following list of advantages is not meant to be limiting
but highlights some of the discoveries contained herein.
[0016] First, a biomass material can be used as the initial
feedstock to prepare the levulinic acid, hydroxymethyl furfural
and/or formic acid. This ability provides great flexibility in
obtaining a constant source of starting material and is not
limiting.
[0017] Second, the biomass can be a refined material, such as
fructose, glucose, sucrose, mixtures of those materials and the
like. As such, there is a plentiful supply of materials that can be
converted into the ultimate product(s). For example, sugar beets or
sugar cane can be used as one source. Fructose-corn syrup or
glucose syrup are other readily available materials. Use of such
materials thus helps to reduce the costs to prepare the desired
products.
[0018] Third, it has been discovered that use of high
concentrations of acid(s), generally about 20 weight percent or
more (based on the total mass of the reaction medium) provides a
cleaner reaction product with less char and unwanted byproducts. It
has also been found that use of high concentrations of acid(s),
generally up to 80 weight percent or more, (based on the total mass
of the reaction medium) provides faster reaction times than lower
acid concentrations used with the same reaction conditions.
[0019] Fourth, it has also been discovered that with the use of
higher concentrations of acid, the reaction conditions can be
conducted at much lower temperatures than are currently utilized in
the literature. Again, this lessens the amount of char and
byproducts from the reaction(s) that take place and increases the
yield of the desired product(s).
[0020] Fifth, it has also been discovered that with the methods of
the present invention, the char that is created is much easier to
remove from the reactor and the char remains well-dispersed in the
reaction medium.
[0021] Sixth, it has also been found that the advantages of the new
process conditions, including continuous addition of the biomass
over a period of time during the reaction can be incorporated into
existing processes to improve yield, reduce costs, improve
efficiency and improve purity of product(s).
[0022] Seventh, the processes described herein can be performed via
CSTR or continuous batch process conditions.
[0023] Eighth, an integrated process with recycling and removal of
impurities is also provided herein.
[0024] Ninth, use of highly selective extraction solvents which
extract LA, but minimal amounts of sulfuric acid from the reaction
medium are provided herein.
[0025] In one embodiment, This process uses a high concentration of
sulfuric acid, which has several distinct advantages. For one, the
reactions can be run at lower temperatures compared to low acid
processes and still hydrolyze the sugars in a reasonable time
frame. It has been discovered that under these high acid,
low-temperature reaction conditions (e.g., 60-160.degree. C.,
preferably, 80-150.degree. C., and more preferably, 90-140.degree.
C.), the char byproduct that is formed is in the form of suspended
particles that are easier to remove from the reactor and that can
be filtered from the liquid hydrolysate product stream. In
contrast, with low acid conditions, high temperature is required to
effectively hydrolyze the sugar in a reasonable time frame and
those conditions produce a char byproduct that coats the reactor
components in such a manner that it is difficult to remove without
mechanical or hydraulic energy, and for the most part does not stay
suspended in the reaction mixture. This high-acid reaction
strategy, however, makes it difficult to isolate the organic acid
products (levulinic acid and formic acid) from the mineral acid
reagent. When small amounts of sulfuric acid are used, as is
typical in the prior art, the strong inorganic acid can effectively
be neutralized to its salt form by careful addition of
stoichiometric amounts of base. At the high acid contents used
here, however, the quantity of salt produced would be excessive.
Likewise, the use of an ion exchange column is impractical because
the large quantity of inorganic acid would quickly fill the
capacity of the column.
[0026] Solvent extraction techniques, where the organic acids are
preferably extracted into an organic solvent, are preferred. Even
here, the high mineral acid content poses challenges. The organic
solvent should be insoluble in the aqueous phase, but in some
cases, the sulfuric acid can drive compatibility of the organic
solvent and the aqueous phase. When this happens, a portion of the
organic solvent becomes soluble in the concentrated sulfuric acid
aqueous phase and the risk of solvent loss to side reactions
increases. Even if the organic solvent is stable in the aqueous
sulfuric acid phase, the organic solvent must be recovered from the
aqueous stream before recycling the raffinate back to the reaction
unit in order to maintain optimum reaction selectivity to form LA
or inoperability due to solids agglomeration in the reactor due to
side reactions with the extraction solvent. High mineral acid
concentration also carries with it the potential for higher mineral
acid concentrations in the organic extract phase. When this
happens, there is the risk of solvent loss and LA loss to side
reactions catalyzed by the mineral acid, particularly in the case
when the organic stream is heated to distill the organic solvent.
Therefore, solvent extraction of the organic acid products should
ideally have at least some of the following characteristics:
[0027] little to no miscibility with water;
[0028] little to no miscibility with the mineral acid;
[0029] selectively partition the organic acids into the organic
solvent phase;
[0030] have low partitioning of the mineral acid into the organic
solvent phase;
[0031] have low reactivity between the organic extraction solvent
and the mineral acid;
[0032] have low reactivity between the organic extraction solvent
& the organic acid products;
[0033] have the ability to remove or reduce any mineral acid that
partitions into the organic phase;
[0034] easy to remove from organic acid, such as by backwashing or
distillation;
[0035] allow the neutralization or water-washing of the mineral
acid.
[0036] In one embodiment, the partition coefficient of the
extraction solvent for levulinic acid is at least 0.3, more
specifically, at least 0.5, more specifically, at least 0.7, more
specifically, at least 1.0, more specifically at least 1.3, more
specifically, at least 1.5 more specifically, at least 1.7, and
more specifically at least 2.0, 3 and 4. In one embodiment, the
partition coefficient of the extraction solvent for formic acid is
at least 0.3, more specifically, at least 0.5, more specifically,
at least 0.7, more specifically, at least 1.0, more specifically at
least 1.3, more specifically, at least 1.5 more specifically, at
least 1.7, and more specifically at least 2.0, more specifically,
at least 2.3, more specifically, at least 2.5, more specifically,
at least 3.0, more specifically, at least 3.5, more specifically,
at least 4.0, more specifically, at least 5.0 more specifically, at
least 6.0, more specifically, at least 7.0, more specifically, at
least 8.0, and more specifically, at least 9.0.
[0037] In one aspect, the invention is directed to a process to
make crystallizable levulinic acid ("LA") from sugar solutions.
[0038] Hydrolysis of an aqueous solution of sucrose, glucose,
fructose, or blends of the aforementioned, specifically fructose
and sucrose, occurs in a batch or continuous reactor, specifically
a continuously fed batch-reactor. In one embodiment the method
includes the following steps following hydrolysis of a solution of
sucrose, glucose, fructose, or blends of the aforementioned:
[0039] (a) Filtration of solids from hydrolysate mixture.
[0040] (b) Water or extraction solvent wash of solids
(optional).
[0041] (c) Extraction of LA and formic acid from aqueous
hydrolysate into an extraction solvent.
[0042] (d) Removal of extraction solvent by distillation.
[0043] (e) Optional Thin-film evaporation of LA.
[0044] (f) Optional Crystallization of LA
[0045] (g) Recycling of extraction solvent to liquid extraction
step.
[0046] (h) Recycling of raffiante phase back to reactor.
[0047] (i) recovery of formic acid.
[0048] The process allows fast reaction time, easy to handle char
byproduct, good yields, no neutralization step (optional),
efficient extraction and distillation to afford a crystallizable LA
product.
[0049] A few processes are known to make LA from sugar, but little
is known on how to remove the LA and formic acid from the reactor
and purify it from the hydrolysate. The disclosed process produces
approximately >80% purity LA that may be distilled or
crystallized to a purity>95%.
[0050] Unless otherwise noted, the concentration of sulfuric acid
used is 96-98%.
[0051] Integrated Process Description
[0052] An integrated process to synthesize and isolate levulinic
acid (LA) using recycled mineral acid is described herein. The
integrated process includes:
[0053] a) providing an aqueous solution of >1% LA in an aqueous
mixture comprising 20-80% by weight mineral acid and >0.1%
suspended solids from the method comprising the steps:
[0054] b) heating an aqueous solution of a mineral acid to a
temperature from about 60.degree. C. to about 160.degree. C. in a
reactor, wherein the mineral acid is present from at least 20
percent by weight to about 80 percent by weight; and
[0055] c) adding a monosaccharide or di-saccharide to the heated
aqueous acid in the reactor to form a reaction mixture at a rate
such that the monosaccharide content of the reaction mixture
remains less than or equal to about 5% by weight of the reaction
mixture, to provide levulinic acid; and
[0056] d) removing the suspended solids by filtration to make a
filtrate with <0.099% suspended solids,
[0057] e) optionally, washing the solids with water or an aqueous
base solution and optionally combining the wash with the
filtrate
[0058] f) extracting the LA from the filtrate of step b (and
optionally, c) using an extraction solvent comprising, preferably,
a phenolic or substituted phenolic compounds to provide an extract
phase containing levulinic and formic acid and a raffinate phase;
and
[0059] g) removing the strong acid impurities from the extract
phase to a level below 1%, prior to formic acid separation or
extract solvent distillation; and
[0060] h) removing formic acid by evaporation or distillation from
the solvent and levulinic acid; and
[0061] i) removing the solvent from levulinic acid and recycling it
back into an extraction unit; and
[0062] j) evaporating or distilling any excess water and formic
acid form the raffinate phase;
[0063] k) removing any extraction solvent, preferably, a phenolic
or substituted phenolic solvent impurities from the raffinate phase
to a level below 1%; and
[0064] l) recycling the raffinate back to the reactor in order to
recycle the acid catalyst in the raffinate.
[0065] Preferable LA concentrations in the aqueous solution of step
a) are >1%, >2%, >4%, >5%, preferably between
5-10%.
[0066] Preferable strong acid concentration in the solvent phase in
step g) is <0.8%, <0.5%, <0.2%, and more preferably
<0.1%.
[0067] Preferably the extraction solvent is a phenolic or
substituted phenolic solvent comprises cresol isomers, 2,4-xylenol,
or mixtures of xylenol isomers.
[0068] Step g) may be accomplished by extraction with water,
neutralization with a weak base anion exchange resin, or
neutralization with an inorganic base; <0.1%, <0.05%, or
<0.01% levels of strong acid are preferred.
[0069] Preferably the amount of water used in step g) is <20% by
weight of the extract.
[0070] Preferably the inorganic base in step g) is an aqueous
solution of NaOH, NaHCO.sub.3, Na.sub.2CO.sub.3, Ca(OH).sub.2,
CaCO.sub.3, Na.sub.3PO.sub.4, K.sub.3PO.sub.4,
Ca.sub.3(PO.sub.4).sub.2, BaCO.sub.3, Ba(OH).sub.2, NH.sub.3,
NH.sub.4OH or mixtures thereof.
[0071] Step k) may be accomplished by adsorption with activated
carbon or by extraction with a hydrocarbon solvent; Preferably the
solvent used in step i) is a C5-C24 straight chain, cyclic, or
branched hydrocarbon, an aromatic hydrocarbon, or mineral oil.
[0072] Preferably the level of phenolic or substituted phenolic
solvent in the raffinate is <0.1%, <0.05%, or <0.02% prior
to step 1).
[0073] The process steps (a-1) may be continuous, batch, or
semi-continuous. The process may comprise holding tanks in between
steps. The process may also contain purge streams for the recycled
raffinate stream and the recycled solvent stream.
[0074] Continuous-Fed Batch Description
[0075] A batch reactor comprises an initial mixture of sulfuric
acid and water, wherein the sulfuric acid concentration is 20-80 wt
% of the mixture. The mixture is heated to a temperature of
60-160.degree. C. The contents are stirred with an agitator and
optionally recirculated in the reactor. An aqueous solution
comprising mono-saccharides and/or di-saccharides is continuously
added into the reactor such that the concentration of
monosaccharides or the intermediate, 5-hydroxymethyl-2-furaldehyde
(HMF) does not exceed 5% by weight of the total mixture at any
moment in time. Alternatively, the aqueous solution of
monosaccharides and disaccharides is continuously added into the
reactor such that the feed rate is between 0.15-80 lbs/hour per 100
pounds of the initial mixture of sulfuric acid and water. After the
addition of mono-saccharides and di-saccharides, the reaction
mixture is optionally held for 5-180 minutes between 60-160.degree.
C. Alternatively, after the addition of monosaccharides and
disaccharides into the reactor, the reaction mixture is heated to
120-160.degree. C. and held for 5-180 minutes. The reaction mixture
is emptied from the reactor when the total amount of
monosaccharides is <2%, preferably <1%, more preferably
<0.1% and when the total amount of HMF is <1%, preferably
<0.1%, more preferably <0.05%
[0076] Other embodiments: the sugar feeds may be heated from
40-110.degree. C. prior to addition into the reactor.
[0077] After the reaction, the contents may be cooled when flowing
out of the reactor or the reaction mixture may be cooled in the
reactor prior to emptying the reaction mixture out of the
reactor.
[0078] The char or solids remains suspended in the reaction mixture
throughout the entire reaction.
[0079] Examples of continuous addition batch reactions are shown in
Examples 1 through 8 in the following examples section.
[0080] Biomass
[0081] Biomass, as used herein, includes sludges from paper
manufacturing process; agricultural residues; bagasse pity;
bagasse; molasses; aqueous oak wood extracts; rice hull; oats
residues; wood sugar slops; fir sawdust; corncob furfural residue;
cotton balls; raw wood flour; rice; straw; soybean skin; soybean
oil residue; corn husks; cotton stems; cottonseed hulls; starch;
potatoes; sweet potatoes; lactose; sunflower seed husks; sugar;
corn syrup; hemp; waste paper; wastepaper fibers; sawdust; wood;
residue from agriculture or forestry; organic components of
municipal and industrial wastes; waste plant materials from hard
wood or beech bark; fiberboard industry waste water;
post-fermentation liquor; furfural still residues; and combinations
thereof, sugar, a C6 sugar, a lignocelluloses, cellulose, starch, a
polysaccharide, a disaccharide, a monosaccharide or mixtures
thereof.
[0082] Reactors
[0083] One, optionally two, reactors are used to convert fructose
to the desired products. The reactors are optionally vented to
maintain an internal pressure; the vent stream is optionally
collected to recover steam and formic acid product; the vent stream
can all be returned to the reactor as a reflux. If there are two
reactors in series, the first reactor is optionally controlled at a
different temperature and at a high concentration of acid in order
to achieve desired conversion and selectivity. The first reactor
would generally be controlled at a lower temperature than the
second. Optionally, a process step between the two reactors may be
used to separate "tar" solids and/or to preferentially extract the
reaction products (away from the aqueous feed) to feed into the
second reactor.
[0084] The reactors may be operated in a batch-wise (wherein the
reactants are continuously or pulsed-fed to the reactor and the
reaction continues until the desired degree of conversion, and the
products are then emptied from the reactor) or in a continuous
fashion (wherein reactants are fed continuously and the products
are removed continuously). In one embodiment, the reactors are run
in a continuously-fed batch fashion. In another embodiment, the
reactors are run in a continuous mode.
[0085] The agitation in the reactors should be adequate to prevent
agglomeration of solid co-products which may be formed during the
reaction. Specifically, the reactors should be designed with
sufficient axial flow (from the center of the reactor to the outer
diameter and back).
[0086] Flash (Optional)
[0087] The reaction products may be optionally cooled in a "flash"
process. The flash step rapidly cools the reaction products by
maintaining a pressure low enough to evaporate a significant
fraction of the products. This pressure may be at or below
atmospheric pressure. The evaporated product stream may be refluxed
through stages of a distillation column to minimize the loss of
desired reaction products, specifically levulinic acid, and to
ensure recovery of formic acid reaction.
[0088] The "bottoms" or less volatile stream from the flash step is
advanced to the solids separation stage.
[0089] Solids Separation
[0090] In the solids separation stage of the process, the solvent
and desired reaction products, specifically levulinic acid and
formic acid, are separated from any solids which may have formed
during the reaction phase. The solids may be separated through a
combination of centrifuge, filtration, and settling steps (ref
Perrys Chemical Engineering Handbook, Solids Separation). The
separated solids may be optionally washed with water and solvents
to recover desired reaction products or solvent which may be
entrained in or adsorbed to the solids. It has been found that in
some embodiments, such as those reactions employing high levels of
mineral acid (greater than 20%) that are reacted at lower
temperatures, such as between 60-160.degree. C., the solids may
have density properties similar to the liquid hydrolysate which
effectively allows the solids to be suspended in solution. In these
embodiments, certain separation techniques such as centrifugation
are not as effective. In these embodiments filtration utilizing
filter media having a pore size less than about 20 microns has been
found to effectively remove solids from the mixture. When removing
solids from the system a solid "cake" is formed. It is desirable
that the cake be up to 50% solids. Thus any separation technique
that obtains a cake having a higher amount of solids is preferred.
A certain amount of LA and mineral acid will be present in the cake
and it may be desirable to wash the cake with an extraction solvent
or water to recover LA.
[0091] It has also been surprisingly found that the solid particles
in the high mineral acid and lower temperature embodiments are
easily filtered and do not inhibit flow as the cake is formed. It
is believed that the properties of the char formed under these
process conditions are such that any cake remains porous enough
that a small filter size (less than 20 microns) can be utilized
while maintaining a high flow rate through the medium.
[0092] The isolated solids may be incinerated to generate power or
disposed.
[0093] The liquid stream, comprising (but not limited to) water,
acid, solvent, levulinic acid, formic acid, and some "soluble tars"
are advanced to the extraction stage of the process.
[0094] Extraction
[0095] In the extraction stage of the process, the liquid stream is
mixed with an extraction solvent stream. The preferred extraction
solvent dissolves levulinic acid more effectively than the other
products in the liquid stream. The preferred solvent does not
dissolve significantly into the water phase. Extraction
configurations are preferably multi-stage and continuous, as
described in Perry's Chemical Engineering Handbook. The extraction
system may be in a vertical column, preferably in which the fluids
are contacted in a counter current fashion. The extraction system
may be a KARR.RTM. (KMPS, Inc.) or SCHEIBEL.RTM. column (KMPS,
Inc.), a packed column, or a tray-type column. The column may have
multiple stages. The extraction system may also be a fractional
extraction system. A water-wash may also be conducted on the
solvent phase after the extraction solvent has contacted the
aqueous reactor composition in the extraction system. The
extractions system may be conducted at temperatures from
20-90.degree. C. The extraction system may contain mixing
stages.
[0096] Alternatively, the extraction system may contain one or more
mixer-settlers in series that allow extraction of LA form the
aqueous reactor composition into the extraction solvent. The
mixer-settler system may have multiple stages. A water-wash may
also be conducted on the solvent phase after the extraction solvent
has contacted the aqueous reactor composition in the mixer-settler
extraction system. The mixer-settler extraction system may be
conducted at temperatures from 20-90.degree. C. The mixer-settler
extraction system may contain one or more mixing stages and one or
more settling stages.
[0097] Suitable extraction solvents include, for example but are
not limited to, phenol, 4-methoxyphenol, 2-methoxyphenol,
3-methoxyphenol, 2-sec-butyl phenol, 3-sec-butyl phenol,
4-sec-butyl phenol, 2-t-butyl phenol, 4-t-butyl phenol,
2,4-di-t-butyl phenol, 2,4-di-methoxyphenol, 2-methylphenol,
3-methylphenol, 4-methylphenol, 2,3-xylenol, 2, 4-xylenol,
2,5-xylenol, 2, 6-xylenol, 3,4-xylenol, or 3,5-xylenol,
4-hexyl-resorcinol, butylated hydroxyl-toluene (BHT),
2,5-dimethoxyphenol, 3,5-dimethoxy phenol, 2,6-dimethoxy phenol,
nonylphenol, or mixtures thereof.
[0098] Additional suitable extraction solvent include, for example
but are not limited to, methyl isoamyl ketone, methyl isobutyl
ketone, diisobutyl ketone, acetophenone, cyclohexanone, isophorone,
neopentyl alcohol, isoamyl alcohol, n-hexanol, n-heptanol, 2-ethyl
hexanol, n-octanol, 1-nonanol, 1-undecanol, phenol,
4-methoxyphenol, guaiacol, methylene chloride, methyl isobutyl
carbinol, anisole, ethylene glycol di-n-butyl ether, castor oil,
1H, 1H, 2H, 2H-pentadecafluorooctanoic acid, 1H, 1H, 2H,
2H-pentadecafluorooctanol, 2-ethyl-hexanoic acid,
propyl-substituted bisphenols with PDMS linking groups, diethyl
carbonate, halogen-substituted phenols or bisphenols, and mixtures
thereof.
[0099] The aqueous raffinate is recycled to the reactor phase,
after optional distillation or purification steps to adjust the
relative concentrations of solvent, water, and acid in the
raffinate.
[0100] The extract solvent phase contains levulinic acid and formic
acid and is progressed to the solvent removal stage of the
process.
[0101] Suitable solvents to extract LA include, for example, polar
water-insoluble solvents such as p-methoxy-phenol and
2,4-xylenol/2,5-xylenol mixtures. Such solvents are used generally
at room temperature so as not to serve as potential reaction
component.
[0102] Solvent Removal
[0103] Levulinic acid may be separated from the solvent phase by
evaporating or distilling the solvent. Alternatively, the levulinic
acid may be crystallized from the solvent phase in a
crystallization process. The solvent removal process may be a
combination of distillation and crystallization. The recovered
solvent may be recycled to the extraction step.
[0104] The resulting stream of highly concentrated levulinic acid
may be advanced for further chemical derivatization or may be
further purified in another distillation step such as high vacuum
wipe-film-evaporation, crystallization or falling film evaporation.
Preferably the levulinic acid stream is kept at a low temperature
throughout the solvent removal steps to inhibit the formation of
angelica lactone.
[0105] Mineral Acids
[0106] Suitable acids used to convert the biomass materials
described herein, including sugars, include mineral acids, such as
but not limited, to sulfuric acid, hydrochloric acid, hydrobromic
acid, hydroiodic acid, hydrofluoric acid, perchloric acid and
mixtures thereof.
[0107] The invention will be further described with reference to
the following non-limiting Examples. It will be apparent to those
skilled in the art that many changes can be made in the embodiments
described without departing from the scope of the present
invention. Thus the scope of the present invention should not be
limited to the embodiments described in this application, but only
by embodiments described by the language of the claims and the
equivalents of those embodiments. Unless otherwise indicated, all
percentages are by weight.
Analytical Methods:
[0108] HPLC Methods
[0109] 1. Waters LC 2695 with PDA 2998
[0110] Column Hamilton.times.300 7 .mu.m 250.times.4.1 mm
[0111] Flow: Isocratic 2.0 mL/min
[0112] Sample Temp Target 25.0.degree. C., Column Temp Target
50.0.degree. C.
[0113] Mobile Phase: 20% Methanol 80% 20 mN Phosphoric acid
[0114] 2. Waters LC 2695 with PDA 2998
[0115] Column: Hamilton.times.300 7 .mu.m 250.times.4.1 mm
[0116] Flow: Gradient 2.0 mL/min
[0117] Sample Temp Target 25.0.degree. C., Column Temp Target
50.0.degree. C.
[0118] Mobile Phase: Solvent B=Methanol, Solvent D=20 mN Phosphoric
acid in deionized water
TABLE-US-00001 Gradient Table Time Flow % B % D 1 2.00 0.00 100.0 2
0.50 2.00 0.00 100.0 3 0.51 2.00 12.0 88.0 4 5.00 2.00 12.0 88.0 5
10.00 2.00 40.0 60.0 6 13.00 2.00 40.0 60.0 7 13.01 2.00 0.0 100.0
8 15.00 2.00 0.0 100.0
[0119] 3. Waters LC 2695 with RI 2414
[0120] Column: Bio-Rad Aminex HPX-87H, 300.times.7.8 mm
[0121] Flow: Isocratic 0.60 mL/min
[0122] Sample Temp Target 25.0.degree. C., Column Temp Target
50.0.degree. C.
[0123] Mobile Phase: 20 mM Phosphoric acid in deionized water with
3% Acetonitrile
[0124] 4. Waters LC 2695 with RI 2414
[0125] Column: Supelcosil LC-NH.sub.2
[0126] Flow: Isocratic 1.0 mL/min
[0127] Sample Temp Target 25.0.degree. C., Column Temp Target
50.0.degree. C.
[0128] Mobile Phase: 80% Acetonitrile 20% Water 20 mM Phosphoric
acid
[0129] Char Washing Method (Unless Otherwise Specified)
[0130] The char was placed in a Buchner funnel and first washed
with 2.times.250 mL deionized water and a spatula was used to break
up the char cake so that it was fully dispersed in the water on the
Buchner funnel. After the water wash the char was washed with 250
mL of acetone.
[0131] Moisture Analyzer
[0132] Mettler Toledo HG63 Halogen Moisture Analyzer Drying
Temperature: 125.degree. C.
Example 1 (2.5 hr Con-Add)
[0133] Into a beaker containing a magnetic stir bar charged 43.25 g
(0.24 mol) fructose and 50.08 g deionized water. The beaker was
placed on a stir plate to dissolve the fructose. Into a 500 mL four
neck round bottom flask containing a magnetic stir bar charged
11.84 g deionized water and 153.35 g (1.00 mol) 64% sulfuric acid.
The round bottom flask was situated in a heating mantle and
equipped with a thermocouple, condenser, glass stopper and syringe
pump tube. The sulfuric acid and water mixture was heated to
90.degree. C. while stirring at a rate of 650 RPM. Once the
fructose was all dissolved it was charged into two 60 mL syringes
and situated into a syringe pump. Once the acid and water mixture
was up to temperature the fructose solution started to be added via
the syringe pump. The fructose solution was added over a course of
2.5 hours at a rate of 30.8 mL/hr. The concentration of fructose
did not exceed 0.7%, and the concentration of HMF did not exceed
0.4% during the monosaccharide addition into the reactor. After all
of the fructose had been added, the reaction was left to react for
an additional hour and then was shut down and allowed to cool to
ambient temperature. The solids that were formed remained suspended
in the reactor during the entire reaction. Once the reaction
mixture was cool it was filtered through a glass microfiber 1.1
.mu.m filter paper. The solids were then washed with DI water and
acetone. The moisture analyzer was used to determine the amount of
solids in the reaction mixture. The results of the experiment
showed 57.91 mol % yield of LA, 68.01 mol % yield of FA and an LA
to char ratio of 2.18 using HPLC method 3.
Example 2 (2.5 hr Con-Add)
[0134] The same procedure was followed as in Example 1 with
different charged weights and two different feed rates were used to
add in the fructose solution. 43.28 g (0.24 mol) fructose and 25.03
g deionized water. 36.86 g deionized water and 153.41 g (1.00 mol)
64% sulfuric acid. For the first 75 minutes of the reaction the
syringe pump rate was set to 25.48 ml/hr then for the remaining 75
minutes the syringe pump rate was set to 13.72 mL/hr. The
concentration of fructose did not exceed 1%, and the concentration
of HMF did not exceed 0.5% during the monosaccharide addition into
the reactor. The solids that were formed remained suspended in the
reactor during the entire reaction. The results of the experiment
showed 59.11 mol % yield of LA, 67.47 mol % yield of FA and an LA
to char ratio of 2.42 using HPLC method 3.
Example 3 (0.5 hr Con-Add)
[0135] The same procedure was followed as in Example 1 with
different charged weights and all of the fructose was added over 30
minutes. 36.12 g (0.20 mol) fructose and 30.05 g deionized water.
97.29 g deionized water and 88.27 g (0.90 mol) sulfuric acid. The
syringe pump was set to a rate of 106 mL/hr. The concentration of
fructose did not exceed 3.5%, and the concentration of HMF did not
exceed 1.5% during the monosaccharide addition into the reactor.
The solids that were formed remained suspended in the reactor
during the entire reaction. The results of the experiment showed
69.08 mol % yield of LA, 70.72 mol % yield of FA and an LA to char
ratio of 2.75 using HPLC method 2 and 4.
Example 4 (0.5 hr Con-Add)
[0136] The same procedure was followed as in Example 1 with
different charged weights. 37.90 g (0.21 mol) fructose and 26.03 g
deionized water. 102.08 g deionized water and 102.99 g (1.05 mol)
sulfuric acid. The syringe pump was set to a rate of 94 mL/hr. The
concentration of fructose did not exceed 2.5%, and the
concentration of HMF did not exceed 1% during the monosaccharide
addition into the reactor. The solids that were formed remained
suspended in the reactor during the entire reaction. The results of
the experiment showed 82.28 mol % yield of LA, 92.14 mol % yield of
FA and an LA to char ratio of 3.03 using HPLC method 1 and 4.
Comparative Example 5 (0.17 hr Con-Add)
[0137] The same procedure was followed as in Example 1 with
different charged weights and all of the fructose was added over 10
minutes. 37.92 g (0.21 mol) fructose and 26.06 g deionized water.
102.07 g deionized water and 103.18 g (1.05 mol) sulfuric acid. The
syringe pump was set to 287.4 mL/hr. The concentration of fructose
did exceeded 5%, and the concentration of HMF exceeded 1% during
the monosaccharide addition into the reactor. The solids that were
formed remained suspended in the reactor during the entire
reaction. However, the LA yield was below 60 mol % yield. The
results of the experiment showed 50.59 mol % yield of LA, 69.15 mol
% yield of FA and an LA to char ratio of 2.17 using HPLC method 1
and 4.
Example 6 (1.25 hr Con-Add)
[0138] The same procedure was followed as in Example 1 with
different charged weights and all of the fructose was added over
1.25 hours. 38.03 g (0.21 mol) fructose and 25.60 g deionized
water. 102.57 g deionized water and 103.04 g (1.05 mol) sulfuric
acid. The syringe pump was set to 37.6 mL/hr. The concentration of
fructose did not exceed 1.5%, and the concentration of HMF did not
exceed 0.7% during the monosaccharide addition into the reactor.
The solids that were formed remained suspended in the reactor
during the entire reaction. The results of the experiment showed
81.37 mol % yield of LA, 95.03 mol % yield of FA and an LA to char
ratio of 3.48 using HPLC method 1 and 4.
Example 7 (2.5 hr Con-Add)
[0139] The same procedure was followed as in Example 1 with
different charged weights. 37.89 g (0.21 mol) fructose and 25.06 g
deionized water. 103.09 g deionized water and 103.03 g (1.05 mol)
sulfuric acid. The syringe pump was set to 18.8 mL/hr. The
concentration of fructose did not exceed 0.6%, and the
concentration of HMF did not exceed 0.5% during the monosaccharide
addition into the reactor. The solids that were formed remained
suspended in the reactor during the entire reaction. The results of
the experiment showed 92.89 mol % yield of LA, 103.37 mol % yield
of FA and an LA to char ratio of 3.75 using HPLC method 1 and
4.
Example 8 (6 hr Con-Add)
[0140] The same procedure was followed as in Example 1 with
different charged weights and all of the fructose was added over 6
hours. 37.87 g (0.21 mol) fructose and 23.05 g deionized water.
105.13 g deionized water and 103.00 g (1.05 mol) sulfuric acid. The
syringe pump was set to 6.5 mL/hr. The concentration of HMF did not
exceed 0.5% during the monosaccharide addition into the reactor.
The solids that were formed remained suspended in the reactor
during the entire reaction. Once the reaction mixture was cool it
was filtered through a fritted glass funnel and the solids were
washed with 2.times.20 mL deionized water and then 2.times.20 mL
methylene chloride. The solids were left to air dry overnight and
the next day were placed into a vacuum oven to dry until a constant
weight was achieved. The results of the experiment showed 78.69 mol
% yield of LA, 91.89 mol % yield of FA and an LA to char ratio of
2.84 using HPLC method 1 and 4.
[0141] In another set of examples:
[0142] Reagents
[0143] Formic acid
[0144] Supplier: Alfa Aesar
[0145] Purity: 97%
[0146] Sulfuric acid
[0147] Supplier: Sigma-Aldrich
[0148] Purity: 95-98%
[0149] Levulinic acid
[0150] Supplier: Sigma Aldrich
[0151] Purity=98%
[0152] LBX-98
[0153] Supplier: Merisol
[0154] Mixture of 66.9% 2,4 xylenol and 30.6% 2,5 xylenol
[0155] LBX-98 mixture (Composition A)
[0156] 11.24% levulinic acid
[0157] 1.15% formic acid
[0158] 0.41% sulfuric acid
[0159] 87.2% LBX-98
Example 9
[0160] A 20 mL centrifuge tube was charged with 9.0 g of
Composition A and 1.0 g of DI Water. The centrifuge tube was shaken
for 30 seconds to mix the two layers. The sample rested at room
temperature (17-23.degree. C.) for 30 minutes to allow the layers
to separate. The sample was then placed inside a 45.degree. C. oven
for 5 minutes to allow the layers to separate.
[0161] Sample rested, at room temperature, overnight to allow
separation to continue. Separation layer was marked and sample was
shaken. Sample rested at room temperature for 15 minutes to allow
layers to separate. Sample then placed in a sandbath inside a
60.degree. C. oven for 15 minutes. After checking for layer
separation, samples were placed back into the oven for an
additional 15 minutes. Sample rested in oven overnight and layers
were separated via pipette while still warm.
Example 10
[0162] Same as example 9 but with 8.5 g of Composition A and 1.5 g
DI Water.
Example 11
[0163] Same as example 9 but with 8.0 g Composition A and 2.0 g DI
Water.
Example 12
[0164] Two 20 mL centrifuge tubes were charged with 8.0 g of
Composition A and 2.0 g of DI Water. Before mixing, samples were
heated to 50.degree. C. in an oven. The centrifuge tubes were
removed and shaken for 30 seconds to mix the layers. Samples were
placed back into the oven and monitored for layer separation.
Example 13
[0165] (a) Reagents combined in example 12 were used for example
13(a) in addition to a 20 mL centrifuge tube that was charged with
8.0 g of Composition A and 2.0 g of DI Water. Before mixing,
samples were heated to 60.degree. C. in an oven. The centrifuge
tubes were removed and shaken for 30 seconds to mix the layers.
Samples were placed back into the oven and monitored for layer
separation.
[0166] (b) Reagents combined in example 13(a) were used for example
5(b) at 70.degree. C.
[0167] (c) Reagents combined in example 13(b) were used for example
5(c) at 80.degree. C.
[0168] (d) Reagents combined in example 13(c) were used for example
5(d) at 90.degree. C.
Example 14
[0169] A 20 mL centrifuge tube was charged with 8.0 g Composition A
and 2.0 g of DI Water. Before mixing, sample was heated to
60.degree. C. in an oven. The centrifuge tube was removed and
shaken for 30 seconds to mix the layers. Sample was placed back
into the oven and monitored for layer separation.
TABLE-US-00002 TABLE 1 Water wash data of varying percent water
wash Example 9 Example 10 Example 11 Layer Solvent Aqueous Solvent
Aqueous Solvent Aqueous H2SO4 (%) 0.05 11.90 0.03 4.50 0.02 2.55 LA
(%) 9.90 4.45 9.43 4.70 9.15 4.62 FA (%) 1.03 4.18 0.85 3.52 0.69
2.91 Partition 2.22 2.01 1.98 Coefficient (LA) Partition 0.25 0.24
0.24 Coefficient (FA) Partition 17691 75359 213907 Coefficient (SA)
in Water LA/H2SO4 207.9 320.0 486.7 Ratio in Solvent layer
TABLE-US-00003 TABLE 2 Water wash data of varying temperature
during separation Example 13(d) Example 13(d) Example 13(d) Example
14 Layer Solvent Aqueous Solvent Aqueous Solvent Aqueous Solvent
Aqueous H2SO4 (%) 0.03 2.58 0.02 2.56 0.02 2.54 0.03 2.67 LA (%)
9.19 4.34 9.19 4.35 9.10 4.38 8.95 4.30 FA (%) 0.72 3.08 0.71 3.09
0.70 3.00 0.64 2.82 Partition Coefficient (LA) 2.12 2.11 2.08 2.08
Partition Coefficient (FA) 0.23 0.23 0.23 0.23 Partition
Coefficient (SA) in 154746 166370 149288 121329 Water LA/H2SO4
Ratio in Solvent 365.7 396.2 348.4 277.2 layer
TABLE-US-00004 TABLE 3 Time to maximum separation Temperature Time
to Maximum of Separation Height of Aqueous Layer Example (.degree.
C.) (min) 12 50 840 13(a) 52 840 14 65 120 13(b) 70 120 13(c) 80 30
13(d) 90 30
[0170] In another series of experiments:
[0171] Formic acid
[0172] Supplier: Alfa Aesar
[0173] Purity: 97%
[0174] Sulfuric acid
[0175] Supplier: Sigma-Aldrich
[0176] Purity: 95-98%
[0177] Levulinic acid
[0178] Supplier: Sigma Aldrich
[0179] Purity 98%
[0180] LBX-98
[0181] Supplier: Merisol
[0182] Mixture of 66.9% 2,4 xylenol and 30.6% 2,5 xylenol
[0183] Composition B
[0184] 6.3% levulinic acid
[0185] 0.73% formic acid
[0186] 0.58% sulfuric acid
[0187] >90% LBX-98
Example 15
[0188] A 2 L Erlenmeyer flask was charged with 957 grams of
Composition B. By HPLC and titration Composition B extract
contained 6.3% levulinic acid, 0.73% formic acid, and 0.58%
sulfuric acid. To the flask, 10 grams (1.1 moles NaOH) of 50 wt %
sodium hydroxide solution was added. The mixture was mixed well and
allowed to sit overnight. Observable solid salts were present on
the bottom of the flask the next day. De-ionized water was slowly
added while the mixture stirred until the salts had completely
dissolved. A total of 58 grams of water was added to the 2 L flask.
The extract was separated from the water layer containing the salt
by pouring off the organic phase into a new 1 L flask. By HPLC and
titration the neutralized extract phase contained 6.0% levulinic
acid, 0.69% formic acid and non-detect sulfuric acid.
[0189] In still another set of experiments:
[0190] Reagents
[0191] m-cresol
[0192] Supplier: Acros
[0193] Purity: 99%
[0194] mixed cresol
[0195] Supplier: LANXESS
[0196] 70% m-cresol; 29.5% p-cresol
[0197] isoamyl alcohol
[0198] Supplier: Sigma Aldrich
[0199] Purity: .gtoreq.98%
[0200] methyl isobutyl carbinol
[0201] Supplier: Alfa Aesar
[0202] Purity: 99%
[0203] 2,4-xylenol
[0204] Supplier: Alfa Aesar
[0205] Purity: 98%
[0206] Formic acid
[0207] Supplier: Alfa Aesar
[0208] Purity: 97%
[0209] Sulfuric acid
[0210] Supplier: Sigma-Aldrich
[0211] Purity: 95-98%
[0212] Levulinic acid
[0213] Supplier: Sigma Aldrich
[0214] Purity 98%
Example 16
[0215] (a) An aqueous solution charged with 40% Sulfuric Acid and
8% levulinic acid. A 20 mL centrifuge tube was charged with 5 g of
the aqueous solution and 5 g of m-cresol as the extraction solvent.
Centrifuge tube was shaken for 30 seconds to thoroughly mix the
layers. Centrifuge tube was centrifuged for 15 minutes to separate
the layers. Sample layers were separated via pipette into
scintillation vials.
[0216] (b) Same as example 16(a) but used mixed cresols as the
extraction solvent.
[0217] (c) Same as example 16(a) but used isoamyl alcohol as the
extraction solvent.
[0218] (d) Same as example 16(a) but used methyl isobutyl carbinol
as the extraction solvent.
[0219] (e) Same as example 16(a) but used 2,4-xylenol as the
extraction solvent.
Example 17
[0220] (a) An aqueous solution charged with 40% Sulfuric Acid and
2% levulinic Acid. A 20 mL centrifuge tube was charged with 5 g of
the aqueous solution and 5 g of m-cresol as the extraction solvent.
Centrifuge tube was shaken for 30 seconds to thoroughly mix the
layers. Centrifuge tube was centrifuged for 15 minutes to separate
the layers. Sample layers were separated via pipette into
scintillation vials.
[0221] (b) Same as example 17(a) but used mixed cresols as the
extraction solvent.
[0222] (c) Same as example 17(a) but used isoamyl alcohol as the
extraction solvent.
[0223] (d) Same as example 17(a) but used methyl isobutyl carbinol
as the extraction solvent.
[0224] (e) Same as example 17(a) but used 2,4-xylenol as the
extraction solvent.
Example 18
[0225] (a) An aqueous stock solution charged with 40% Sulfuric Acid
and 8% Formic Acid. A 20 mL centrifuge tube was charged with 5 g of
the aqueous solution and 5 g of m-cresol as the extraction solvent.
Centrifuge tube was shaken for 30 seconds to thoroughly mix the
layers. Centrifuge tube was centrifuged for 15 minutes to separate
the layers. Sample layers were separated via pipette into
scintillation vials.
[0226] (b) Same as example 18(a) but used mixed cresols as the
extraction solvent.
[0227] (c) Same as example 18(a) but used isoamyl alcohol as the
extraction solvent.
[0228] (d) Same as example 18(a) but used methyl isobutyl carbinol
as the extraction solvent.
[0229] (e) Same as example 18(a) but used 2,4-xylenol as the
extraction solvent.
Example 19
[0230] (a) An aqueous solution charged with 40% Sulfuric Acid and
2% Formic Acid. A 20 mL centrifuge tube was charged with 5 g of the
aqueous solution and 5 g of m-cresol as the extraction solvent.
Centrifuge tube was shaken for 30 seconds to thoroughly mix the
layers. Centrifuge tube was centrifuged for 15 minutes to separate
the layers. Sample layers were separated via pipette into
scintillation vials.
[0231] (b) Same as example 19(a) but used mixed cresols as the
extraction solvent.
[0232] (c) Same as example 19(a) but used isoamyl alcohol as the
extraction solvent.
[0233] (d) Same as example 19(a) but used 2,4-xylenol as the
extraction solvent.
Example 20
[0234] (a) An aqueous stock solution charged with 40% Sulfuric
Acid, 6% Levulinic Acid and 2% Formic Acid. A 20 mL centrifuge tube
was charged with 5 g of the aqueous solution and 5 g of m-cresol as
the extraction solvent. Centrifuge tube was shaken for 30 seconds
to thoroughly mix the layers. Centrifuge tube was centrifuged for
15 minutes to separate the layers. Sample layers were separated via
pipette into scintillation vials.
[0235] (b) Same as example 20(a) but used mixed cresols as the
extraction solvent.
[0236] (c) Same as example 20(a) but used isoamyl alcohol as the
extraction solvent.
[0237] (d) Same as example 20(a) but used methyl isobutyl carbinol
as the extraction solvent.
[0238] (e) Same as example 20(a) but used 2,4-xylenol as the
extraction solvent.
Example 21
[0239] (a) An aqueous stock solution charged with 40% Sulfuric
Acid, 4% Levulinic Acid and 4% Formic Acid. A 20 mL centrifuge tube
was charged with 5 g of the aqueous solution and 5 g of m-cresol as
the extraction solvent. Centrifuge tube was shaken for 30 seconds
to thoroughly mix the layers. Centrifuge tube was centrifuged for
15 minutes to separate the layers. Sample layers were separated via
pipette into scintillation vials.
[0240] (b) Same as example 21(a) but used mixed cresols as the
extraction solvent.
[0241] (c) Same as example 21(a) but used isoamyl alcohol as the
extraction solvent.
[0242] (d) Same as example 21(a) but used methyl isobutyl carbinol
as the extraction solvent.
[0243] (e) Same as example 21(a) but used 2,4-xylenol as the
extraction solvent.
Example 22
[0244] (a) An aqueous stock solution charged with 40% Sulfuric
Acid, 2% Levulinic Acid and 6% Formic Acid. A 20 mL centrifuge tube
was charged with 5 g of the aqueous solution and 5 g of m-cresol as
the extraction solvent. Centrifuge tube was shaken for 30 seconds
to thoroughly mix the layers. Centrifuge tube was centrifuged for
15 minutes to separate the layers. Sample layers were separated via
pipette into scintillation vials.
[0245] (b) Same as example 22(a) but used mixed cresols as the
extraction solvent.
[0246] (c) Same as example 22(a) but used isoamyl alcohol as the
extraction solvent.
[0247] (d) Same as example 22(a) but used methyl isobutyl carbinol
as the extraction solvent.
[0248] (e) Same as example 22(a) but used 2,4-xylenol as the
extraction solvent.
Example 23
[0249] (a) An aqueous stock solution charged with 40% Sulfuric
Acid, 8% Levulinic Acid and 3% Formic Acid. A 20 mL centrifuge tube
was charged with 5 g of the aqueous solution and 5 g of m-cresol as
the extraction solvent. Centrifuge tube was shaken for 30 seconds
to thoroughly mix the layers. Centrifuge tube was centrifuged for
15 minutes to separate the layers. Sample layers were separated via
pipette into scintillation vials.
[0250] (b) Same as example 23(a) but used mixed cresols as the
extraction solvent.
[0251] (c) Same as example 23(a) but used isoamyl alcohol as the
extraction solvent.
[0252] (d) Same as example 23(a) but used methyl isobutyl carbinol
as the extraction solvent.
[0253] (e) Same as example 23(a) but used 2,4-xylenol as the
extraction solvent.
Example 24
[0254] (a) An aqueous stock solution charged with 40% Sulfuric Acid
and 6% Levulinic Acid. A 20 mL centrifuge tube was charged with 5 g
of the aqueous solution and 5 g of m-cresol as the extraction
solvent. Centrifuge tube was shaken for 30 seconds to thoroughly
mix the layers. Centrifuge tube was centrifuged for 15 minutes to
separate the layers. Sample layers were separated via pipette into
scintillation vials.
[0255] (b) Same as example 24(a) but used mixed cresols as the
extraction solvent.
[0256] (c) Same as example 24(a) but used 2,4-xylenol as the
extraction solvent.
Example 25
[0257] (a) An aqueous stock solution charged with 40% Sulfuric Acid
and 4% Levulinic Acid. A 20 mL centrifuge tube was charged with 5 g
of the aqueous solution and 5 g of m-cresol as the extraction
solvent. Centrifuge tube was shaken for 30 seconds to thoroughly
mix the layers. Centrifuge tube was centrifuged for 15 minutes to
separate the layers. Sample layers were separated via pipette into
scintillation vials.
[0258] (b) Same as example 25(a) but used mixed cresols as the
extraction solvent.
[0259] (c) Same as example 25(a) but used 2,4-xylenol as the
extraction solvent.
Example 26
[0260] (a) Aqueous stock solution charged with 60% Sulfuric Acid,
6% Levulinic Acid and 2% Formic Acid. A 20 mL centrifuge tube was
charged with 5 g of the aqueous solution and 5 g of 2,4-xylenol as
the extraction solvent. Centrifuge tube was shaken for 30 seconds
to thoroughly mix the layers. Centrifuge tube was centrifuged for
15 minutes to separate the layers. Sample layers were separated via
pipette into scintillation vials.
[0261] (b) Same as example 26(a) but used 60% Sulfuric Acid, 4%
Levulinic Acid, and 4% Formic Acid as the aqueous.
[0262] (c) Same as example 26(a) but used 60% Sulfuric Acid, 42%
Levulinic Acid, and 6% Formic Acid as the aqueous.
[0263] (d) Same as example 26(a) but used 60% Sulfuric Acid, 8%
Levulinic Acid, and 3% Formic Acid as the aqueous.
[0264] (e) Same as example 26(a) but used 60% Sulfuric Acid and 8%
Levulinic Acid as the aqueous.
[0265] (f) Same as example 26(a) but used 60% Sulfuric Acid and 6%
Levulinic Acid as the aqueous.
[0266] (g) Same as example 26(a) but used 60% Sulfuric Acid and 4%
Levulinic Acid as the aqueous.
[0267] (h) Same as example 26(a) but used 60% Sulfuric Acid and 2%
Levulinic Acid as the aqueous.
Example 27
[0268] (a) Aqueous stock solution charged with 20% Sulfuric Acid,
6% Levulinic Acid and 2% Formic Acid. A 20 mL centrifuge tube was
charged with 5 g of the aqueous solution and 5 g of 2,4-xylenol as
the extraction solvent. Centrifuge tube was shaken for 30 seconds
to thoroughly mix the layers. Centrifuge tube was centrifuged for
15 minutes to separate the layers. Sample layers were separated via
pipette into scintillation vials.
[0269] (b) Same as example 27(a) but used 20% Sulfuric Acid, 4%
Levulinic Acid, and 4% Formic Acid as the aqueous.
[0270] (c) Same as example 27(a) but used 20% Sulfuric Acid, 42%
Levulinic Acid, and 6% Formic Acid as the aqueous.
[0271] (d) Same as example 27(a) but used 20% Sulfuric Acid, 8%
Levulinic Acid, and 3% Formic Acid as the aqueous.
[0272] (e) Same as example 27(a) but used 20% Sulfuric Acid and 8%
Levulinic Acid as the aqueous.
[0273] (f) Same as example 27(a) but used 20% Sulfuric Acid and 6%
Levulinic Acid as the aqueous.
[0274] (g) Same as example 27(a) but used 20% Sulfuric Acid and 4%
Levulinic Acid as the aqueous.
[0275] (h) Same as example 27(a) but used 20% Sulfuric Acid and 2%
Levulinic Acid as the aqueous.
TABLE-US-00005 TABLE 4 Example 16(a) Example 16(b) Example 16(c)
Example 16(d) Example 16(e) Layer Solvent Aqueous Solvent Aqueous
Solvent Aqueous Solvent Aqueous Solvent Aqueous LA (%) 6.96 1.76
7.21 1.85 0.65 1.83 0.85 4.36 6.57 2.03 Partition 3.95 3.90 0.36
0.19 3.24 Coefficient (LA)
TABLE-US-00006 TABLE 5 Example 17(a) Example 17(b) Example 17(c)
Example 17(d) Example 17(e) Layer Solvent Aqueous Solvent Aqueous
Solvent Aqueous Solvent Aqueous Solvent Aqueous LA (%) 1.90 0.41
1.92 0.40 0.19 0.65 0.30 1.04 1.81 0.49 Partition 4.63 4.80 0.29
0.29 3.69 Coefficient (LA)
TABLE-US-00007 TABLE 6 Example 18(a) Example 18(b) Example 18(c)
Example 18(d) Example 18(e) Layer Solvent Aqueous Solvent Aqueous
Solvent Aqueous Solvent Aqueous Solvent Aqueous FA (%) 2.47 7.35
2.5 7.23 5.24 0.84 1.76 1.16 1.86 7.53 Partition 0.34 0.35 6.24
1.52 0.25 Coefficient (FA)
TABLE-US-00008 TABLE 7 Example 19(a) Example 19(b) Example 19(c)
Example 19(d) Layer Solvent Aqueous Solvent Aqueous Solvent Aqueous
Solvent Aqueous FA (%) 0.62 1.87 0.62 1.87 1.27 0.36 0.95 0.89
Partition 0.33 0.33 3.53 1.07 Coefficient (FA)
TABLE-US-00009 TABLE 8 Example 20(a) Example 20(b) Example 20(c)
Example 20(d) Example 20(e) Layer Solvent Aqueous Solvent Aqueous
Solvent Aqueous Solvent Aqueous Solvent Aqueous LA (%) 4.47 1.28
4.95 1.3 0.5 1.66 0.87 2.95 4.790 1.540 FA (%) 0.65 1.88 0.65 1.88
1.31 0.18 0.73 0.34 0.540 1.930 Partition 3.49 3.81 0.30 0.29 3.11
Coefficient (LA) Partition 0.35 0.35 7.28 2.15 0.28 Coefficient
(FA)
TABLE-US-00010 TABLE 9 Example 21(a) Example 21(b) Example 21(c)
Example 21(d) Example 21(e) Layer Solvent Aqueous Solvent Aqueous
Solvent Aqueous Solvent Aqueous Solvent Aqueous LA (%) 3.66 0.86
3.36 0.84 0.37 1.19 1.05 1.88 3.280 1.010 FA (%) 1.31 3.55 1.24
3.54 2.75 0.37 1.3 0.62 1.050 3.650 Partition 4.26 4.00 0.31 0.56
3.25 Coefficient (LA) Partition 0.37 0.35 7.43 2.10 0.29
Coefficient (FA)
TABLE-US-00011 TABLE 10 Example 22(a) Example 22(b) Example 22(c)
Example 22(d) Example 22(e) Layer Solvent Aqueous Solvent Aqueous
Solvent Aqueous Solvent Aqueous Solvent Aqueous LA (%) 2 0.46 1.73
0.44 0.24 0.67 1.25 1.1 1.650 0.530 FA (%) 1.87 5.16 1.86 5.16 4.19
0.55 1.98 0.88 1.500 5.310 Partition 4.35 3.93 0.36 1.14 3.11
Coefficient (LA) Partition 0.36 0.36 7.62 2.25 0.28 Coefficient
(FA)
TABLE-US-00012 TABLE 11 Example 23(a) Example 23(b) Example 23(c)
Example 23(d) Example 23(e) Layer Solvent Aqueous Solvent Aqueous
Solvent Aqueous Solvent Aqueous Solvent Aqueous LA (%) 6.35 1.79
6.33 1.78 0.63 2.29 1.17 3.9 5.980 2.140 FA (%) 0.9 2.61 0.91 2.68
1.83 0.25 0.95 0.42 0.780 2.710 Partition 3.55 3.56 0.28 0.30 2.79
Coefficient (LA) Partition 0.34 0.34 7.32 2.26 0.29 Coefficient
(FA)
TABLE-US-00013 TABLE 12 Example 24(a) Example 24(b) Example 24(c)
Layer Solvent Aqueous Solvent Aqueous Solvent Aqueous LA (%) 4.91
1.14 5.03 1.14 3.921 1.704 Partition 4.31 4.41 2.30 Coefficient
(LA)
TABLE-US-00014 TABLE 13 Example 25(a) Example 25(b) Example 25(c)
Layer Solvent Aqueous Solvent Aqueous Solvent Aqueous LA (%) 2.93
0.70 3.27 0.71 2.63 1.08 Partition 4.19 4.61 2.43 Coefficient
(LA)
TABLE-US-00015 TABLE 14 Example 26(a) Example 26(b) Example 26(c)
Example 26(d) Layer Solvent Aqueous Solvent Aqueous Solvent Aqueous
Solvent Aqueous H2SO4 (%) 0.688 N/D 0.629 N/D 0.628 N/D 1.261 N/D
LA (%) 2.426 3.467 1.616 2.362 0.645 1.531 2.273 6.461 FA (%) 0.344
1.672 0.690 3.323 0.763 6.350 0.406 3.328 Partition 0.70 0.68 0.42
0.35 Coefficient (LA) Partition 0.21 0.21 0.12 0.12 Coefficient
(FA) N/D = not determined
TABLE-US-00016 TABLE 15 Example 26(e) Example 26(f) Example 26(g)
Example 26(h) Layer Solvent Aqueous Solvent Aqueous Solvent Aqueous
Solvent Aqueous H2SO4 (%) 0.727 N/D 0.562 N/D 0.490 N/D 0.368 N/D
LA (%) 2.524 5.958 2.075 4.082 1.456 2.540 0.747 1.202 Partition
0.42 0.51 0.57 0.62 Coefficient (LA) N/D = not determined
TABLE-US-00017 TABLE 16 Example 27(a) Example 27(b) Example 27(c)
Example 27(d) Layer Solvent Aqueous Solvent Aqueous Solvent Aqueous
Solvent Aqueous H2SO4 (%) N/D N/D 0.097 N/D 0.017 N/D 0.025 N/D LA
(%) 5.573 1.051 3.789 0.718 1.543 0.462 5.682 1.695 FA (%) 0.055
1.886 1.039 3.758 1.167 7.095 0.062 3.719 Partition 5.30 5.28 3.34
3.35 Coefficient (LA) Partition 0.03 0.28 0.16 0.02 Coefficient
(FA) N/D = not determined
TABLE-US-00018 TABLE 17 Example 27(e) Example 27(f) Example 27(g)
Example 27(h) Layer Solvent Aqueous Solvent Aqueous Solvent Aqueous
Solvent Aqueous H2SO4 (%) 0.019 N/D 0.254 N/D 0.111 N/D 0.010 N/D
LA (%) 5.978 1.650 4.553 1.227 3.016 0.814 1.494 0.401 Partition
3.62 3.71 3.71 3.72 Coefficient (LA) N/D = not determined
[0276] In still more examples:
Example 28
[0277] Into a 1 L four neck round bottom flask containing a
magnetic stir bar charged 171.23 g DI water, 357.85 g (2.34 mol)
sulfuric acid (64%) and 3.01 g m-Cresol. The round bottom flask was
situated in a heating mantle and equipped with a thermocouple,
condenser, glass stopper, and a syringe pump inlet. The water,
sulfuric acid and cresol mixture was heated to 90.degree. C. while
stirring at 500 RPM. Into a 60 mL syringe charged 59.02 g (42 mL)
Cornsweet 90. (Corn Sweet 90 is a high-fructose syrup (90%
fructose, 8.5% glucose, 1.5% oligiomeric sugars) supplied by Archer
Daniels Midland (ADM). It contains 77% solids.)
[0278] Once the sulfuric acid, water and cresol mixture reached a
temperature of 90.degree. C. the cornsweet 90 started to be added
to the mixture via a syringe pump at a rate of 16.8 mL/hr. After
2.5 hours, all of the cornsweet 90 had been added to the round
bottom flask and the reaction mixture was left to react for an
additional hour. After a total reaction time of 3.5 hours the heat
was turned off and the reaction mixture was allowed to cool to
ambient temperature. Once the reaction mixture was cool it was
filtered through a 1.1 .mu.m glass microfiber filter. The char was
then washed with methanol and DI water and measured using a
moisture analyzer. Samples were pulled throughout the reaction and
analyzed by HPLC.
[0279] Reaction observations: After 60 minutes of reaction time
there appeared to be a plastic looking film on the surface of the
reaction mixture and the mixture itself looked thick. It was not
apparent whether or not the magnetic stir bar was still stirring.
Once the reaction was filtered it was very clear that the magnetic
stir bar had indeed stopped stirring because it was completely
encased by a very hard solid substance which had stuck to the
bottom of the round bottom flask. The char formed clumps and seemed
to have some shiny attributes to it.
TABLE-US-00019 Time % % % % % % Sample (min) Glucose Fructose FA LA
HMF Cresol Example 210 0.86 0.00 1.22 2.71 0.01 0.00 28 LA Molar %
Yield 57.68 FA Molar % Yield 65.50 LA to Char Ratio 1.95
Example 29
[0280] Into a 1 L four neck round bottom flask containing a
magnetic stir bar charged 171.61 g DI water, 357.81 g (2.33 mol)
sulfuric acid (64%) and 924 .mu.L (7.7 mmol) 2,4-Xylenol. The round
bottom flask was situated in a heating mantle and equipped with a
thermocouple, condenser, glass stopper, and a syringe pump inlet.
The water, sulfuric acid and xylenol mixture was heated to
90.degree. C. while stirring at 500 RPM. Into a 60 mL syringe
charged 59.03 g (43 mL) cornsweet 90. Once the sulfuric acid, water
and xylenol mixture reached a temperature of 90.degree. C. the
cornsweet 90 started to be added to the mixture via a syringe pump
at a rate of 17.2 mL/hr. After 2.5 hours, all of the cornsweet 90
had been added to the round bottom flask and the reaction mixture
was left to react for an additional hour. After a total reaction
time of 3.5 hours the heat was turned off and the reaction mixture
was allowed to cool to ambient temperature. Once the reaction
mixture was cool it was filtered through a 1.1 .mu.m glass
microfiber filter. The char was then washed with DI water and
measured using a moisture analyzer. Samples were pulled throughout
the reaction and analyzed by HPLC.
[0281] Reaction Observations: After 40 minutes of reaction time
there was a plastic looking film on the surface of the reaction
mixture and the reaction mixture looked thick. It was not apparent
whether or not the magnetic stir bar was still stirring. A foam
ball had formed in the center of the flask and when a spatula was
used to try to break up the char it was unsuccessful because the
char was so hard. Once the reaction mixture was filtered and all of
the liquid had been poured out of the round bottom flask it was
very clear that the magnetic stir bar had stopped stirring because
it was completely encased by a very hard char substance which also
covered the entire bottom of the flask. The char formed clumps and
seemed to have some shiny attributes to it.
TABLE-US-00020 Time % % % % % % Sample (min) Glucose Fructose FA LA
HMF Xylenol Example 20 0.08 0.34 0.00 0.05 0.08 0.04 29A Example
210 0.80 0.00 1.19 2.73 0.00 0.00 29B LA Molar % Yield 58.05 FA
Molar % Yield 64.02 LA to Char Ratio 1.94
Example 30
[0282] Into a 1 L four neck round bottom flask containing a
magnetic stir bar charged 171.21 g DI water, 357.85 g (2.34 mol)
sulfuric acid (64%) and 578 .mu.L (4.8 mmol) 2,4-Xylenol. The round
bottom flask was situated in a heating mantle and equipped with a
thermocouple, condenser, glass stopper, and a syringe pump inlet.
The water, sulfuric acid and xylenol mixture was heated to
90.degree. C. while stirring at 500 RPM. Into a 60 mL syringe
charged 59.02 g (43 mL) cornsweet 90. Once the sulfuric acid, water
and xylenol mixture reached a temperature of 90.degree. C. the
cornsweet 90 started to be added to the mixture via a syringe pump
at a rate of 17.2 mL/hr. After 2.5 hours, all of the cornsweet 90
had been added to the round bottom flask and the reaction mixture
was left to react for an additional hour. After a total reaction
time of 3.5 hours the heat was turned off and the reaction mixture
was allowed to cool to ambient temperature. Once the reaction
mixture was cool it was filtered through a 1.1 .mu.m glass
microfiber filter. The char was then washed with DI water and
measured using a moisture analyzer. Samples were pulled throughout
the reaction and analyzed by HPLC.
[0283] Reaction Observations: After 40 minutes of reaction time, it
was apparent that the magnetic stir bar had stopped stirring but it
was able to be dislodged from the bottom of the flask by poking
with the Teflon coated thermocouple. The char had to be broken up
again after 120 minutes of reaction time. When the reaction mixture
was filtered and all of the liquid had been poured out of the
flask, there was not much char stuck to the reactor. There was char
stuck to the magnetic stir bar and it was hard.
TABLE-US-00021 Time % % % % % Sample (min) Glucose Fructose FA LA
HMF Example 210 0.81 0.00 1.20 2.91 0.00 30 LA Molar % Yield 64.60
FA Molar % Yield 68.16 LA to Char Ratio 2.51
Example 31
[0284] Into a 1 L four neck round bottom flask containing a
magnetic stir bar charged 171.30 g DI water, 357.87 g (2.34 mol)
sulfuric acid (64%) and 462.10 .mu.L (3.9 mmol) 2,4-Xylenol. The
round bottom flask was situated in a heating mantle and equipped
with a thermocouple, condenser, glass stopper, and a syringe pump
inlet. The water, sulfuric acid and xylenol mixture was heated to
90.degree. C. while stirring at 500 RPM. Into a 60 mL syringe
charged 58.98 g (43 mL) cornsweet 90. Once the sulfuric acid, water
and xylenol mixture reached a temperature of 90.degree. C. the
cornsweet 90 started to be added to the mixture via a syringe pump
at a rate of 17.2 mL/hr. After 2.5 hours, all of the cornsweet 90
had been added to the round bottom flask and the reaction mixture
was left to react for an additional hour. After a total reaction
time of 3.5 hours the heat was turned off and the reaction mixture
was allowed to cool to ambient temperature. Once the reaction
mixture was cool it was filtered through a 1.1 .mu.m glass
microfiber filter. The char was then washed with DI water and
measured using a moisture analyzer. Samples were pulled throughout
the reaction and analyzed by HPLC.
[0285] Reaction Observations: After 40 minutes of reaction time, it
was apparent that the magnetic stir bar had stopped stirring but it
was able to be dislodged from the bottom of the flask by poking
with the Teflon coated thermocouple. When the reaction mixture was
filtered and all of the liquid had been poured out of the flask,
there was not much char stuck to the glass but there was some very
hard char stuck to the magnetic stir bar.
TABLE-US-00022 Time % % % % % Sample (min) Glucose Fructose FA LA
HMF Example 210 0.81 0.00 1.20 2.92 0.00 31 LA Molar % Yield 64.04
FA Molar % Yield 66.80 LA to Char Ratio 2.55
Example 32
[0286] Into a 1 L four neck round bottom flask containing a
magnetic stir bar charged 171.21 g DI water, 357.89 g (2.34 mol)
sulfuric acid (64%) and 231.04 .mu.L (1.9 mmol) 2.4-Xylenol. The
round bottom flask was situated in a heating mantle and equipped
with a thermocouple, condenser, glass stopper, and a syringe pump
inlet. The water, sulfuric acid and xylenol mixture was heated to
90.degree. C. while stirring at 500 RPM. Into a 60 mL syringe
charged 58.99 g (43 mL) cornsweet 90. Once the sulfuric acid, water
and xylenol mixture reached a temperature of 90.degree. C. the
cornsweet 90 started to be added to the mixture via a syringe pump
at a rate of 17.2 mL/hr. After 2.5 hours, all of the cornsweet 90
had been added to the round bottom flask and the reaction mixture
was left to react for an additional hour. After a total reaction
time of 3.5 hours the heat was turned off and the reaction mixture
was allowed to cool to ambient temperature. Once the reaction
mixture was cool it was filtered through a 1.1 .mu.m glass
microfiber filter. The char was then washed with DI water and
measured using a moisture analyzer. Samples were pulled throughout
the reaction and analyzed by HPLC.
[0287] Reaction Observations: When the magnetic stir bar was
removed from the flask at the end of the reaction there were some
small spots of hard char visibly stuck to the magnetic stir bar.
When all of the liquid had been poured out of the flask there was a
ring of char that was left but it was easily removed when squirted
with DI water.
TABLE-US-00023 Time % % % % % % Sample (min) Glucose Fructose FA LA
HMF Xylenol Example 210 0.81 0.00 1.22 3.05 0.00 0.00 32 LA Molar %
Yield 66.12 FA Molar % Yield 66.80 LA to Char Ratio 2.75
Example 33
[0288] Into a 1 L four neck round bottom flask containing a
magnetic stir bar charged 171.21 g DI water, 357.85 g (2.34 mol)
sulfuric acid (64%) and 28.88 .mu.L (0.24 mmol) 2,4-Xylenol. The
round bottom flask was situated in a heating mantle and equipped
with a thermocouple, condenser, glass stopper, and a syringe pump
inlet. The water, sulfuric acid and xylenol mixture was heated to
90.degree. C. while stirring at 500 RPM. Into a 60 mL syringe
charged 59.02 g (43 mL) cornsweet 90. Once the sulfuric acid, water
and xylenol mixture reached a temperature of 90.degree. C. the
cornsweet 90 started to be added to the mixture via a syringe pump
at a rate of 17.2 mL/hr. After 2.5 hours, all of the cornsweet 90
had been added to the round bottom flask and the reaction mixture
was left to react for an additional hour. After a total reaction
time of 3.5 hours the heat was turned off and the reaction mixture
was allowed to cool to ambient temperature. Once the reaction
mixture was cool it was filtered through a 1.1 .mu.m glass
microfiber filter. The char was then washed with DI water and
measured using a moisture analyzer. Samples were pulled throughout
the reaction and analyzed by HPLC.
[0289] Reaction Observations: There were no problems stirring the
reaction mixture since the char was well dispersed and did not form
clumps. This char had similar characteristics as to what is
normally observed in a fructose hydrolysis reaction to LA using
these reaction conditions.
TABLE-US-00024 Time % % % % % % Sample (min) Glucose Fructose FA LA
HMF Xylenol Example 210 0.82 0.00 1.23 2.96 0.00 0.00 33 LA Molar %
Yield 68.00 FA Molar % Yield 72.63 LA to Char Ratio 2.85
Example 34
[0290] Into a 1 L four neck round bottom flask containing a
magnetic stir bar charged 171.24 g DI water, 357.88 g (2.34 mol)
sulfuric acid (64%) and 11.55 .mu.L (0.10 mmol) 2,4-Xylenol. The
round bottom flask was situated in a heating mantle and equipped
with a thermocouple, condenser, glass stopper, and a syringe pump
inlet. The water, sulfuric acid and xylenol mixture was heated to
90.degree. C. while stirring at 500 RPM. Into a 60 mL syringe
charged 58.99 g (43 mL) cornsweet 90. Once the sulfuric acid, water
and xylenol mixture reached a temperature of 90.degree. C. the
cornsweet 90 started to be added to the mixture via a syringe pump
at a rate of 17.2 mL/hr. After 2.5 hours, all of the cornsweet 90
had been added to the round bottom flask and the reaction mixture
was left to react for an additional hour. After a total reaction
time of 3.5 hours the heat was turned off and the reaction mixture
was allowed to cool to ambient temperature. Once the reaction
mixture was cool it was filtered through a 1.1 .mu.m glass
microfiber filter. The char was then washed with DI water and
measured using a moisture analyzer. Samples were pulled throughout
the reaction and analyzed by HPLC.
[0291] Reaction observations: There were no problems stirring the
reaction mixture since the char was well dispersed and did not form
clumps. This char had similar characteristics as to what is
normally observed in a fructose hydrolysis using these reaction
conditions.
TABLE-US-00025 Time % % % % % Sample (min) Glucose Fructose FA LA
HMF Example 210 0.81 0.00 1.22 3.02 0.00 34 LA Molar % Yield 67.94
FA Molar % Yield 69.82 LA to Char Ratio 2.81
Example 35
[0292] Into a 1 L four neck round bottom flask containing a
magnetic stir bar charged 171.18 g DI water, 357.91 g (2.34 mol)
sulfuric acid (64%) and 924 .mu.L (7.7 mmol) 2,4-Xylenol. The round
bottom flask was situated in a heating mantle and equipped with a
thermocouple, condenser, and two glass stoppers. The water,
sulfuric acid and xylenol mixture was heated to 110.degree. C.
while stirring at 500 RPM to get the mixture to reflux. After
refluxing for 125 minutes the heat was turned off and the mixture
was allowed to cool to ambient temperature. Once the mixture was
cool it was filtered through a 1.1 .mu.m glass microfiber filter. A
sample of the filtered mixture was taken and analyzed by HPLC which
indicated that there was still 0.13% xylenol after the heat
treatment. The heat treatment step did not effectively remove
xylenol to a low level.
Example 36
[0293] 5 wt % activated carbon was added to the mixture from
Example 35, and the mixture was stirred at ambient temperature for
185 minutes. Samples were pulled after 100 and 185 minutes. The
heat was then turned on to heat up the mixture to 68.7.degree. C.
and once the mixture reached that temperature another sample was
taken. The samples were analyzed by HPLC for Xylenol. The first
sample that was pulled after 100 minutes and mixing at ambient
temperature showed that all of the xylenol had been removed
(non-detect by HPLC). All of the activated carbon was filtered out
of the mixture using a 1.1 .mu.m glass microfiber filter. The
filtered mixture was then charged into a clean 1 L four neck round
bottom flask and equipped with a thermocouple, condenser, glass
stopper, and a syringe pump inlet. The water and sulfuric acid
mixture was heated to 90.degree. C. while stirring at 500 RPM. Into
a 60 mL syringe charged 58.98 g (43 mL) cornsweet 90. Once the
sulfuric acid and water mixture reached a temperature of 90.degree.
C. the cornsweet 90 started to be added to the mixture via a
syringe pump at a rate of 17.2 mL/hr. After 2.5 hours, all of the
cornsweet 90 had been added to the round bottom flask and the
reaction mixture was left to react for an additional hour. After a
total reaction time of 3.5 hours the heat was turned off and the
reaction mixture was allowed to cool to ambient temperature. Once
the reaction mixture was cool it was filtered through a 1.1 .mu.m
glass microfiber filter. The char was then washed with DI water and
measured using a moisture analyzer. Samples were pulled throughout
the reaction and analyzed by HPLC.
[0294] Reaction Observations: There were no problems stirring the
reaction mixture since the char was well dispersed and did not form
clumps. This char had similar characteristics as to what is
normally observed in a fructose hydrolysate under these
conditions.
TABLE-US-00026 Time % % % % % Sample (min) Glucose Fructose FA LA
HMF Example 210 0.94 0.00 1.43 3.41 0.00 36 LA Molar % Yield 76.81
FA Molar % Yield 82.33 LA to Char Ratio 3.09
[0295] Although the present invention has been described with
reference to preferred embodiments, persons skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention. All
references cited throughout the specification, including those in
the background, are incorporated herein in their entirety. Those
skilled in the art will recognize, or be able to ascertain, using
no more than routine experimentation, many equivalents to specific
embodiments of the invention described specifically herein. Such
equivalents are intended to be encompassed in the scope of the
following claims.
* * * * *