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WO1997047579A1 - Methods for synthesis of high purity carboxylic and fatty acids - Google Patents

Methods for synthesis of high purity carboxylic and fatty acids Download PDF

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Publication number
WO1997047579A1
WO1997047579A1 PCT/US1997/010000 US9710000W WO9747579A1 WO 1997047579 A1 WO1997047579 A1 WO 1997047579A1 US 9710000 W US9710000 W US 9710000W WO 9747579 A1 WO9747579 A1 WO 9747579A1
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WO
WIPO (PCT)
Prior art keywords
acid
alcohol
carboxylic
reaction mixture
water insoluble
Prior art date
Application number
PCT/US1997/010000
Other languages
French (fr)
Inventor
Irshad Ahmed
Original Assignee
Renewable Energy Development Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Renewable Energy Development Corporation filed Critical Renewable Energy Development Corporation
Priority to AU33840/97A priority Critical patent/AU3384097A/en
Publication of WO1997047579A1 publication Critical patent/WO1997047579A1/en

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
    • C07C51/493—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification whereby carboxylic acid esters are formed

Definitions

  • the present invention relates to methods for the production of high purity carboxylic and fatty acids. Description of the Related Art
  • a number of carboxylic and fatty acids are important intermediates in the synthesis of hundreds of commercially significant derivative chemicals.
  • applications for levulinic acid derived chemicals include: esters and ester derivatives, for use as solvents, paint strippers, and plasticizers; hydrogenation chemicals for use as fuel additives, pharmaceuticals, electronic and intermediate chemicals, flavors and fragrances; and compounds of levulinic acid produced via reactions with carbonyl reagents and halogens, for use as agricultural, specialty and intermediate chemicals.
  • succinic acid derived chemicals are useful as resins for plastics, plasticizers, plant growth stimulants, food ingredient (salt substitute), flavor additive, acidulant, biophosphors, pharmaceutical intermediates, corrosion inhibitors, soaps and detergents, surfactants, and plating compounds, and other applications.
  • carboxylic and fatty acids derived chemicals such as epoxyethyl levulinate, methyl tetrahydrofuran, valerolactone, 1,4 pentanediol, 1 ,4-butanediol, maleic anhydride, adipic acid, and others for high volume applications.
  • levulinic acid For example, two basic routes are known for the synthesis of levulinic acid.
  • fossil fuel based furfural derived from pyridine is catalytically converted in the presence of an inorganic acid in multi-step Cannizzaro reaction to levulinic acid.
  • This pathway initially yields a low purity levulinic acid, which may be purified to the desired purity or reagent grade via several separation steps, including vacuum distillation, liquid-liquid extraction, and ultra centrifugation.
  • vacuum distillation, liquid-liquid extraction, and ultra centrifugation Unfortunately, this process is prohibitively expensive because of the petroleum feedstock and because of the expensive purification steps required.
  • the second known pathway for synthesizing levulinic acid begins with relatively inexpensive cellulosic feedstock.
  • cellulose is converted to glucose which is converted to hydroxymethylfurfural and levulinic acid via high temperature acid hydrolysis.
  • this pathway typically produces more than one desired product in a reaction mixture comprising only approximately 10 to 15-percent levulinic acid.
  • steam distillation has been used to separate the levulinic acid from the above reaction mixture, steam distillation is relatively expensive.
  • the high temperatures associated with steam distillation cause the levulinic acid to degrade yielding a pale yellow malodorous product, unsuitable for many applications.
  • succinic acid produces maleic anhydride as the primary contaminant along with trace levels of amides and other organic acids including adipic acid, itaconic acid and aspartic acid.
  • amides and other organic acids including adipic acid, itaconic acid and aspartic acid.
  • fatty acids are derived from vegetable oils which contain a mixture of fatty acids that are combined with glycerine.
  • Current commercial applications of fatty acids require separation of fatty acids from glycerine followed by further fractionation of different fatty acids into their purified individual forms.
  • the use of fatty acids in pharmaceuticals, cosmetics and other high value applications require a high degree of purity which through conventional methods of chromatographic and ultra- centrifugation methods have proven to be relatively expensive. It is accordingly an object of this invention to overcome the disadvantages and drawbacks of the known art and to provide methods for the synthesis of high purity carboxylic and fatty acids.
  • a method for separating a carboxylic or fatty acid from a reaction mixture of water soluble components comprising the steps of: (a) esterifying the acid with an alcohol to produce a water insoluble ester; (b) separating the water insoluble ester from the reaction mixture; (c) hydrolyzing the water insoluble ester to yield the acid and the alcohol; and (d) separating the acid from the alcohol.
  • the present invention is based on the discovery that carboxylic and fatty acids can be separated from reaction mixtures containing a variety of water soluble components by ester if ication, separation and hydrolysis as described herein.
  • Methods for producing high purity carboxylic and fatty acids in accordance with the present invention comprise the following steps: (1) esterification of a reaction mixture containing a carboxylic or fatty acid with an alcohol to produce a water insoluble ester; (2) separation of the water insoluble ester from the other components of the reaction mixture; (3) hydrolysis of the water insoluble ester to recover the original carboxylic or fatty acid and the alcohol; and (4) separation of the carboxylic or fatty acid from the alcohol.
  • esterification of the carboxylic or fatty acid in the reaction mixture can be accomplished with a standard Fisher esterification reaction as follows:
  • R is any alkyl or aryl group and R'OH is any suitable alcohol, including without limitation, methyl, ethyl, propyl, butyl, amyl, ethoxyethyl, lauryl, aryoxyalkyl, 2- haloakyl, cyclohexyl, chloromethyldihydrosafrole, tetrahydrofurfuryl , benzyl, cyclohexyl, 2,4,6-trichloro-phenyl, 2,4,6-bromo-phenyl, dimethyl benzyl, 1-napthyl carbinyl, and
  • R'OH is preferably methyl alcohol.
  • a stoichiometric excess of the alcohol is preferably used to insure that all of the carboxylic or fatty acid is esterified.
  • the esterification reaction is preferably performed at a temperature range of 100-150C under atmospheric pressure in the presence of a mineral acid catalyst.
  • the resulting water insoluble ester may be separated from the remaining water soluble components of the reaction mixture by any suitable separation technique, including, without limitation, decantation, vacuum distillation, liquid-liquid extraction, molecular sieves, or a combination thereof.
  • the separation technique is preferably a low temperature technique to protect the ester from degradation.
  • the separated water insoluble ester may then be hydrolyzed to yield the original carboxylic or fatty acid.
  • this step comprises acid hydrolysis with a mineral acid, such as sulfuric or formic acid, to reverse the Fisher esterification.
  • hydrolysis can be achieved with an aqueous base.
  • a stoichiometric excess of the acid is preferably used to ensure that all of the ester is hydrolyzed.
  • the hydrolysis reaction is preferably performed at 118°C temperature under 1 to 1.5 times the atmospheric pressures in the presence of a suitable catalyst, such as sulfuric acid.
  • the carboxylic or fatty acid may then be separated from the alcohol and any other hydrolysis product through any suitable separation technique, including, without limitation, vacuum distillation, centrifugation, chromatographic separation, solvent extraction, filtration using molecular and other conventional techniques.
  • a low temperature membrane separation technique adapted to protect the heat sensitive carboxylic or fatty acid is employed.
  • One such separation method employs micron grade polycarbonate membranes designed specifically for separation of the desired carboxylic or fatty acid.
  • esterification, ester separation, hydrolysis, and carboxylic or fatty acid separation steps may be carried out in a batch processing stirred tank reactor ("STR") or in a continuous processing continuous stirred tank reactor (“CSTR") system. In either case the catalysts and the esterification reactants may be recovered and recycled.
  • STR batch processing stirred tank reactor
  • CSTR continuous processing continuous stirred tank reactor
  • levulinic acid derived from cellulose by acid hydrolysis is esterified with methanol to produce water insoluble methyl levulinate.
  • the reaction mixture containing the levulinic acid may be relatively acidic as a result of the acid hydrolysis, it is preferable to adjust the pH of the reaction mixture by adding sufficient amount of a suitable base, such as ammonium hydroxide, to the reactor prior to the esterification so that the pH of the reaction mixture prior to esterification is between approximately 4 and 5.
  • a suitable base such as ammonium hydroxide
  • the methyl levulinate may be separated from the other reaction products and impurities, which are water soluble, through any suitable separation technique as described above.
  • the separated methyl levulinate may then be hydrolyzed, preferably with sulfuric or formic acid to yield levulinic acid.
  • the levulinic acid produced in the hydrolysis step may be separated from the alcohol and any other reaction products using the separation techniques described above.
  • the theoretical yield of levulinic acid employing the methods of the present invention is 71.6 percent, calculated based on the ratio of the molecular weights of levulinic acid and hexose polymer. It is anticipated that the actual yield of methods in accordance with the present invention will be approximately 60 to 65 percent of the theoretical yield.
  • the methods of the present invention may be applied to any reaction mixture containing a carboxylic or a fatty acid, including without limitation, acetic acid, stearic acid, and lauric acid.
  • the methods of the present invention may be applied to: (1) reaction mixtures containing levulinic acid resulting from the acid hydrolysis of cellulose; (2) reaction mixtures containing levulinic acid resulting from the catalytic conversion of pyridine or furfural; (3) reaction mixtures containing succinic acid resulting from the fermentation of six glucose sugars derived from starch/sugar crops (such as corn, sugarcane, and potatoes), cellulosic biomass (such a paper sludge, saw dust, and corn cobs), and/or from petrochemical ly derived maleic anhydride.
  • the material flow is as shown above. 25.0 lbs. of ground wood is mixed with 42 liters of 4-6% sulfuric acid solution and fed to a batch STR along with steam at 150 psi pressure and 335 °F temperature. The reactor slurry contains 20 percent solids.
  • reaction mixture is filtered to separate solids.
  • the reaction temperature for methyl levulinate formation is dropped to between 100-150°C temperature at 1-1.5 atmospheric pressure in the presence of the sulfuric acid as the catalyst in a STR or a CSTR reactor system.
  • About 2.5 pounds of methanol is then added to the reaction mixture producing a reaction mixture of water insoluble methyl levulinate and other water soluble byproducts and impurities, he methyl levulinate is separated from the reaction mixture using vacuum distillation.
  • Approximately 10 liters of 4-6% sulfuric acid are then added to hydrolyze methyl levulinate producing a reaction mixture containing levulinic acid, methanol and sulfuric acid.
  • the levulinic acid is then separated from the reaction mixture using molecular sieves and/or centrifugation combination.
  • the methanol is regenerated at the end of second hydrolysis and is recycled back to the primary esterification reaction at about 70 to 80% recycling rate.
  • the temperature for esterification reaction is maintained at 118°C.
  • the final product is anticipated to be about 8.5 pounds of purified levulinic acid.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

A method for separating a carboxylic or fatty acid from a reaction mixture of water-soluble components, including the steps of: (a) esterifying the acid with an alcohol to produce a water insoluble ester; (b) separating the water insoluble ester from the reaction mixture; (c) hydrolyzing the water insoluble ester to yield the acid and the alcohol; and (d) separating the acid from the alcohol.

Description

METHODS FOR SYNTHESIS OF HIGH PURITY CARBOXYLIC AND FATTY ACIDS
BACKGROUND OF THR INVENTION Field of the Invention The present invention relates to methods for the production of high purity carboxylic and fatty acids. Description of the Related Art
A number of carboxylic and fatty acids, including particularly levulinic acid, succinic acid, acetic acid, stearic acid, and lauric acid, are important intermediates in the synthesis of hundreds of commercially significant derivative chemicals. For example, applications for levulinic acid derived chemicals include: esters and ester derivatives, for use as solvents, paint strippers, and plasticizers; hydrogenation chemicals for use as fuel additives, pharmaceuticals, electronic and intermediate chemicals, flavors and fragrances; and compounds of levulinic acid produced via reactions with carbonyl reagents and halogens, for use as agricultural, specialty and intermediate chemicals. Similarly, succinic acid derived chemicals are useful as resins for plastics, plasticizers, plant growth stimulants, food ingredient (salt substitute), flavor additive, acidulant, biophosphors, pharmaceutical intermediates, corrosion inhibitors, soaps and detergents, surfactants, and plating compounds, and other applications. Unfortunately, it has proven difficult and expensive to produce high purity carboxylic and fatty acids. Synthesis routes often start with expensive raw materials and frequently involve expensive and sometimes ineffective separation techniques to remove impurities. As a result, it has not been economically practical to produce certain carboxylic and fatty acids derived chemicals, such as epoxyethyl levulinate, methyl tetrahydrofuran, valerolactone, 1,4 pentanediol, 1 ,4-butanediol, maleic anhydride, adipic acid, and others for high volume applications.
For example, two basic routes are known for the synthesis of levulinic acid. In one pathway, fossil fuel based furfural derived from pyridine is catalytically converted in the presence of an inorganic acid in multi-step Cannizzaro reaction to levulinic acid. This pathway initially yields a low purity levulinic acid, which may be purified to the desired purity or reagent grade via several separation steps, including vacuum distillation, liquid-liquid extraction, and ultra centrifugation. Unfortunately, this process is prohibitively expensive because of the petroleum feedstock and because of the expensive purification steps required.
The second known pathway for synthesizing levulinic acid begins with relatively inexpensive cellulosic feedstock. In this pathway, cellulose is converted to glucose which is converted to hydroxymethylfurfural and levulinic acid via high temperature acid hydrolysis. Unfortunately, this pathway typically produces more than one desired product in a reaction mixture comprising only approximately 10 to 15-percent levulinic acid. It has proven extremely difficult to separate the levulinic acid from the other components of the reaction mixture, which typically include among other things, water, hydroxymethylfurfural, mineral acids (sulfuric or hydrochloric), formic acid, and other single carbon compounds. Although steam distillation has been used to separate the levulinic acid from the above reaction mixture, steam distillation is relatively expensive. Moreover, the high temperatures associated with steam distillation cause the levulinic acid to degrade yielding a pale yellow malodorous product, unsuitable for many applications.
Similarly, the production reaction sequence for succinic acid produces maleic anhydride as the primary contaminant along with trace levels of amides and other organic acids including adipic acid, itaconic acid and aspartic acid. Separating such closely related molecules based on molecular weights fractionation as employed in chromatographic separations and molecular sieves is impractical. Other conventional techniques used such as vacuum distillation are energy intensive and hence not viable economically based on high energy costs.
Similarly, a wide variety of fatty acids are derived from vegetable oils which contain a mixture of fatty acids that are combined with glycerine. Current commercial applications of fatty acids require separation of fatty acids from glycerine followed by further fractionation of different fatty acids into their purified individual forms. The use of fatty acids in pharmaceuticals, cosmetics and other high value applications require a high degree of purity which through conventional methods of chromatographic and ultra- centrifugation methods have proven to be relatively expensive. It is accordingly an object of this invention to overcome the disadvantages and drawbacks of the known art and to provide methods for the synthesis of high purity carboxylic and fatty acids.
Further objects and advantages of this invention will become apparent from the detailed description of a preferred embodiment which follows.
SUMMARY OF THR INVENTION A method for separating a carboxylic or fatty acid from a reaction mixture of water soluble components, comprising the steps of: (a) esterifying the acid with an alcohol to produce a water insoluble ester; (b) separating the water insoluble ester from the reaction mixture; (c) hydrolyzing the water insoluble ester to yield the acid and the alcohol; and (d) separating the acid from the alcohol.
DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is based on the discovery that carboxylic and fatty acids can be separated from reaction mixtures containing a variety of water soluble components by ester if ication, separation and hydrolysis as described herein. Methods for producing high purity carboxylic and fatty acids in accordance with the present invention comprise the following steps: (1) esterification of a reaction mixture containing a carboxylic or fatty acid with an alcohol to produce a water insoluble ester; (2) separation of the water insoluble ester from the other components of the reaction mixture; (3) hydrolysis of the water insoluble ester to recover the original carboxylic or fatty acid and the alcohol; and (4) separation of the carboxylic or fatty acid from the alcohol.
In accordance with the present invention, esterification of the carboxylic or fatty acid in the reaction mixture can be accomplished with a standard Fisher esterification reaction as follows:
RCOOH + Impurities + R'OH + H+ > RCOOR' + H2O + Impurities wherein: R is any alkyl or aryl group and R'OH is any suitable alcohol, including without limitation, methyl, ethyl, propyl, butyl, amyl, ethoxyethyl, lauryl, aryoxyalkyl, 2- haloakyl, cyclohexyl, chloromethyldihydrosafrole, tetrahydrofurfuryl , benzyl, cyclohexyl, 2,4,6-trichloro-phenyl, 2,4,6-bromo-phenyl, dimethyl benzyl, 1-napthyl carbinyl, and
(di)chloro-benzyl alcohol. R'OH is preferably methyl alcohol. A stoichiometric excess of the alcohol is preferably used to insure that all of the carboxylic or fatty acid is esterified. The esterification reaction is preferably performed at a temperature range of 100-150C under atmospheric pressure in the presence of a mineral acid catalyst.
Once the desired carboxylic or fatty acid has been esterified, the resulting water insoluble ester may be separated from the remaining water soluble components of the reaction mixture by any suitable separation technique, including, without limitation, decantation, vacuum distillation, liquid-liquid extraction, molecular sieves, or a combination thereof. The separation technique is preferably a low temperature technique to protect the ester from degradation. The separated water insoluble ester may then be hydrolyzed to yield the original carboxylic or fatty acid. In a preferred embodiment of the present invention, this step comprises acid hydrolysis with a mineral acid, such as sulfuric or formic acid, to reverse the Fisher esterification. Alternatively, hydrolysis can be achieved with an aqueous base. Again, a stoichiometric excess of the acid is preferably used to ensure that all of the ester is hydrolyzed. The hydrolysis reaction is preferably performed at 118°C temperature under 1 to 1.5 times the atmospheric pressures in the presence of a suitable catalyst, such as sulfuric acid.
The carboxylic or fatty acid may then be separated from the alcohol and any other hydrolysis product through any suitable separation technique, including, without limitation, vacuum distillation, centrifugation, chromatographic separation, solvent extraction, filtration using molecular and other conventional techniques. Preferably a low temperature membrane separation technique adapted to protect the heat sensitive carboxylic or fatty acid is employed. One such separation method employs micron grade polycarbonate membranes designed specifically for separation of the desired carboxylic or fatty acid.
The esterification, ester separation, hydrolysis, and carboxylic or fatty acid separation steps may be carried out in a batch processing stirred tank reactor ("STR") or in a continuous processing continuous stirred tank reactor ("CSTR") system. In either case the catalysts and the esterification reactants may be recovered and recycled. In a preferred embodiment of the present invention, levulinic acid derived from cellulose by acid hydrolysis is esterified with methanol to produce water insoluble methyl levulinate. Since the reaction mixture containing the levulinic acid may be relatively acidic as a result of the acid hydrolysis, it is preferable to adjust the pH of the reaction mixture by adding sufficient amount of a suitable base, such as ammonium hydroxide, to the reactor prior to the esterification so that the pH of the reaction mixture prior to esterification is between approximately 4 and 5. After esterification, the methyl levulinate may be separated from the other reaction products and impurities, which are water soluble, through any suitable separation technique as described above. The separated methyl levulinate may then be hydrolyzed, preferably with sulfuric or formic acid to yield levulinic acid. Finally, the levulinic acid produced in the hydrolysis step may be separated from the alcohol and any other reaction products using the separation techniques described above.
The theoretical yield of levulinic acid employing the methods of the present invention is 71.6 percent, calculated based on the ratio of the molecular weights of levulinic acid and hexose polymer. It is anticipated that the actual yield of methods in accordance with the present invention will be approximately 60 to 65 percent of the theoretical yield.
The methods of the present invention may be applied to any reaction mixture containing a carboxylic or a fatty acid, including without limitation, acetic acid, stearic acid, and lauric acid. In particular, the methods of the present invention may be applied to: (1) reaction mixtures containing levulinic acid resulting from the acid hydrolysis of cellulose; (2) reaction mixtures containing levulinic acid resulting from the catalytic conversion of pyridine or furfural; (3) reaction mixtures containing succinic acid resulting from the fermentation of six glucose sugars derived from starch/sugar crops (such as corn, sugarcane, and potatoes), cellulosic biomass (such a paper sludge, saw dust, and corn cobs), and/or from petrochemical ly derived maleic anhydride.
The invention will be clarified further by a consideration of the following example, which is intended to be purely exemplary. PROSPRCTIVR EXAMPLE
Cellulose (paper waste) Water Formic Acid
I | 20% solids & Byproducts
| 25 pounds | 42 liters water
I
Feedstock > Slurry > Stage I Acid Levulinic Acid Preparation Preparation Hydrolysis & Byproducts
Methanol Recycle 70%
Purified Methyl Ester < Filtration Levulinic Formation Acid ~8.51bs.
Lignin Residue & Unreacted Sugars
The material flow is as shown above. 25.0 lbs. of ground wood is mixed with 42 liters of 4-6% sulfuric acid solution and fed to a batch STR along with steam at 150 psi pressure and 335 °F temperature. The reactor slurry contains 20 percent solids.
After about 4-5 hours, the reaction mixture is filtered to separate solids. The reaction temperature for methyl levulinate formation is dropped to between 100-150°C temperature at 1-1.5 atmospheric pressure in the presence of the sulfuric acid as the catalyst in a STR or a CSTR reactor system. About 2.5 pounds of methanol is then added to the reaction mixture producing a reaction mixture of water insoluble methyl levulinate and other water soluble byproducts and impurities, he methyl levulinate is separated from the reaction mixture using vacuum distillation. Approximately 10 liters of 4-6% sulfuric acid are then added to hydrolyze methyl levulinate producing a reaction mixture containing levulinic acid, methanol and sulfuric acid. The levulinic acid is then separated from the reaction mixture using molecular sieves and/or centrifugation combination. The methanol is regenerated at the end of second hydrolysis and is recycled back to the primary esterification reaction at about 70 to 80% recycling rate. The temperature for esterification reaction is maintained at 118°C. The final product is anticipated to be about 8.5 pounds of purified levulinic acid. It will be further understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the invention as expressed in the following claims.

Claims

O 97/47579 PC17US97/100008CLAIMS What is claimed is:
1. A method for separating a carboxylic or fatty acid from a reaction mixture of water soluble components, comprising the steps of:
(a) esterifying the acid with an alcohol to produce a water insoluble ester;
(b) separating the water insoluble ester from the reaction mixture;
(c) hydrolyzing the water insoluble ester to yield the acid and the alcohol; and
(d) separating the acid from the alcohol.
2. The method of claim 1 , wherein: the acid is levulinic acid, succinic acid, acetic acid, stearic acid, or lauric acid.
3. The method of claim 1, wherein: the alcohol is methyl, ethyl, propyl, butyl, amyl, ethoxyethyl, lauryl, aryoxyalkyl, 2-haloakyl, cyclohexyl, chloromethyldihydrosafrole, tetrahydrofurfuryl, benzyl, cyclohexyl, 2,4,6-trichloro-phenyl, 2,4,6-bromo-phenyl, dimethyl benzyl, 1- napthyl carbinyl, or (di)chloro-benzyl alcohol.
4. The method of claim 1 , wherein: the acid is levulinic acid.
5. The method of claim 4, wherein: the alcohol is methanol.
6. The method of claim 4, wherein: the alcohol is butanol .
PCT/US1997/010000 1996-06-10 1997-06-09 Methods for synthesis of high purity carboxylic and fatty acids WO1997047579A1 (en)

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US66498796A 1996-06-10 1996-06-10
US08/664,987 1996-06-10

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7378549B2 (en) 2004-01-26 2008-05-27 Shell Oil Company Process for the reactive extractive extraction of levulinic acid
US7501062B2 (en) 2005-02-22 2009-03-10 Shell Oil Company Process for permeation enhanced reactive extraction of levulinic acid
US9073841B2 (en) 2012-11-05 2015-07-07 Segetis, Inc. Process to prepare levulinic acid
US10618864B2 (en) 2011-11-23 2020-04-14 Gfbiochemicals Ip Assets B.V. Process to prepare levulinic acid

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR663425A (en) * 1928-02-17 1929-08-21 Le Ketol Process for the purification of organic acids by fractional distillation of their esters (or ethers-salts) and by subsequent saponification of the latter
US2911420A (en) * 1953-08-12 1959-11-03 Gulf Research Development Co Method for the separation of difficultly separable mixtures of carboxylic acids
GB1282926A (en) * 1968-10-10 1972-07-26 El Paso Products Co Esterification and extraction process
US4058555A (en) * 1969-07-18 1977-11-15 El Paso Products Company Process for the purification of mixed acids

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR663425A (en) * 1928-02-17 1929-08-21 Le Ketol Process for the purification of organic acids by fractional distillation of their esters (or ethers-salts) and by subsequent saponification of the latter
US2911420A (en) * 1953-08-12 1959-11-03 Gulf Research Development Co Method for the separation of difficultly separable mixtures of carboxylic acids
GB1282926A (en) * 1968-10-10 1972-07-26 El Paso Products Co Esterification and extraction process
US4058555A (en) * 1969-07-18 1977-11-15 El Paso Products Company Process for the purification of mixed acids

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7378549B2 (en) 2004-01-26 2008-05-27 Shell Oil Company Process for the reactive extractive extraction of levulinic acid
CN100548966C (en) * 2004-01-26 2009-10-14 国际壳牌研究有限公司 Reactive extraction method of levulinic acid
RU2391333C2 (en) * 2004-01-26 2010-06-10 Шелл Интернэшнл Рисерч Маатсхаппий Б.В. Method for reaction extraction of levulinic acid
US7501062B2 (en) 2005-02-22 2009-03-10 Shell Oil Company Process for permeation enhanced reactive extraction of levulinic acid
US10618864B2 (en) 2011-11-23 2020-04-14 Gfbiochemicals Ip Assets B.V. Process to prepare levulinic acid
US9073841B2 (en) 2012-11-05 2015-07-07 Segetis, Inc. Process to prepare levulinic acid
US9598341B2 (en) 2012-11-05 2017-03-21 Gfbiochemicals Limited Process to prepare levulinic acid

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