CA2657666A1 - Process for the direct production of esters of carboxylic acids from fermentation broths - Google Patents
Process for the direct production of esters of carboxylic acids from fermentation broths Download PDFInfo
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- CA2657666A1 CA2657666A1 CA002657666A CA2657666A CA2657666A1 CA 2657666 A1 CA2657666 A1 CA 2657666A1 CA 002657666 A CA002657666 A CA 002657666A CA 2657666 A CA2657666 A CA 2657666A CA 2657666 A1 CA2657666 A1 CA 2657666A1
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- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
- C12P7/00—Preparation of oxygen-containing organic compounds
- C12P7/40—Preparation of oxygen-containing organic compounds containing a carboxyl group including Peroxycarboxylic acids
- C12P7/44—Polycarboxylic acids
- C12P7/46—Dicarboxylic acids having four or less carbon atoms, e.g. fumaric acid, maleic acid
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/132—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group
- C07C29/136—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH
- C07C29/147—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of carboxylic acids or derivatives thereof
- C07C29/149—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of carboxylic acids or derivatives thereof with hydrogen or hydrogen-containing gases
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/30—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group
- C07C67/317—Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by splitting-off hydrogen or functional groups; by hydrogenolysis of functional groups
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- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
- C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
- C07D307/04—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members
- C07D307/06—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to ring carbon atoms
- C07D307/08—Preparation of tetrahydrofuran
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- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
- C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
- C07D307/26—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member
- C07D307/30—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D307/32—Oxygen atoms
- C07D307/33—Oxygen atoms in position 2, the oxygen atom being in its keto or unsubstituted enol form
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract
A process for producing an ester of carboxylic acid from a fermented broth is provided. The process comprises in one step providing a fermented broth containing at least one carboxylic acid salt. The following step comprises obtaining the ester of carboxylic acid by subjecting the carboxylic acid salt to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst. The process may further include a step wherein the ester of carboxylic acid is further subjected to a catalytic hydrogenation reaction, or a step wherein it is subjected to a catalytic oxidative dehydrogenation reaction.
Description
PROCESS FOR THE DIRECT PRODUCTION OF ESTERS OF
CARBOXYLIC ACIDS FROM FERMENTATION BROTHS
FIELD OF THE INVENTION
The invention relates to a process for the direct production of carboxylic acid esters from salts of the corresponding carboxylic acid produced via fermentation. Specifically, the process features direct integration of the fermentation step with the esterification step.
BACKGROUND OF THE INVENTION
Esters of carboxylic acids are widely used as starting products in chemical synthesis. The use of esters avoids acid corrosion and related corrosion costs and high costs for corrosion resistant equipment associated with the use of the free acid form of theses esters.
Succinate esters can be widely used as solvents, diesel fuel oxygenate, chemical intermediates, monomers for polymerization process, etc.
Moreover, succinate esters represent valuable starting materials for the production of 1,4-butanediol (BDO), tetrahydrofuran (THF), and gamma-butyrolactone (GBL), which are large-volume commodity chemicals.
Biocatalytic processes such as those using numerous fermentable sugars as a substrate are seen as an economical and environmental alternative to traditional petrochemical processes. More particularly, such processes involving conversion of low value carbohydrates, considered as waste products, are of increasing interests.
Succinic acid can be produced by a process using fermentable sugars as a starting material. More particularly, a salt of succinic acid is obtained by conversion of the carbohydrates comprised in the broth in the presence of succinate producing micro-organisms.
CARBOXYLIC ACIDS FROM FERMENTATION BROTHS
FIELD OF THE INVENTION
The invention relates to a process for the direct production of carboxylic acid esters from salts of the corresponding carboxylic acid produced via fermentation. Specifically, the process features direct integration of the fermentation step with the esterification step.
BACKGROUND OF THE INVENTION
Esters of carboxylic acids are widely used as starting products in chemical synthesis. The use of esters avoids acid corrosion and related corrosion costs and high costs for corrosion resistant equipment associated with the use of the free acid form of theses esters.
Succinate esters can be widely used as solvents, diesel fuel oxygenate, chemical intermediates, monomers for polymerization process, etc.
Moreover, succinate esters represent valuable starting materials for the production of 1,4-butanediol (BDO), tetrahydrofuran (THF), and gamma-butyrolactone (GBL), which are large-volume commodity chemicals.
Biocatalytic processes such as those using numerous fermentable sugars as a substrate are seen as an economical and environmental alternative to traditional petrochemical processes. More particularly, such processes involving conversion of low value carbohydrates, considered as waste products, are of increasing interests.
Succinic acid can be produced by a process using fermentable sugars as a starting material. More particularly, a salt of succinic acid is obtained by conversion of the carbohydrates comprised in the broth in the presence of succinate producing micro-organisms.
All commercially viable, succinate producing micro-organisms described in the literature require neutralization of the fermentation broth to maintain an appropriate pH for maximum conversion and productivity. In order to obtain the acid, a cation elimination process is necessary, wherein the base cation needed to neutralize the acid in the fermentation is replaced by protonation with a mineral acid such as sulfuric acid'.2,3 or by electrodialysis4.
Conversion of the salt to the acid and its purification involve several unit operations that could potentially diminish the economic viability of biobased succinic acid as a platform chemical. Furthermore, acidification and purification based processes may not provide economically viable high-grade succinic acid suitable for catalytic processes such as hydrogenation and oxidative dehydrogenation. Hydrogenation products of succinic acid include 1,4-butanediol (BDO), tetrahydrofuran (THF), and gamma-butyrolactone (GBL), which are large volume commodity chemicals. Catalytic oxidative dehydrogenation of succinic acid produces maleic anhydride, which has a demand approaching 1.5 billion kg, worldwide.
The catalysts used for hydrogenation and oxidative dehydrogenation are highly susceptible to deactivation in the presence of trace impurities.
Furthermore, current biobased succinic acid production technologies produce molar equivalents of the conjugate salt (for example, ammonium sulfate) that has to be disposed at considerable expense or further processed to regenerate the acid and base values for reuse within the process. Although electrodialysis, particularly bipolar electrodialysis, has been proposed as a means to convert the carboxylic acid salt to its acid form while simultaneously producing the base values for recycling, the energy consumption can be economically prohibitive.
Processes for the production of esters of carboxylic acids from fermentable broth, avoiding the use of the free carboxylic acid are disclosed in the literature. For example, WO 2007/116005 Al discloses a process for the production of polycarboxylic alkyl esters from aqueous solutions of the ammonium salt of the polycarboxylic acid by reactive distillation and an integrated method for hydrogenating the polycarboxylic alkyl ester. The esterification step is carried out using either heterogeneous or homogenous catalysis. An example of heterogeneous catalyst is an acidic ion exchanger catalyst which is fixed on or in column fittings. However, such structured catalysts are extremely susceptible to impurities, particularly numerous ionic salts that are abundant in fermentation broths. Examples of homogeneous catalysts include p-toluene sulfonic acid or methane sulfonic acid. Such catalysts are added to the aqueous solution of the ammonium salt of the carboxylic acid. However, such catalysts have to be used in significant concentrations and subsequently recovered from the product for recycling.
The catalysts recovery may not be trivial, and the document does not teach any method for the catalysts recovery.
US Patent No. 5,252,473 discloses an integrated process for the production of esters of acrylic acid comprising: (a) fermenting carbohydrate material with a lactic acid producing organism in the presence of NH3 to produce ammonium lactate;(b) combining the ammonium lactate with alcohol and an effective catalyzing amount of CO2 in a conventional single-stage esterification process to catalytically esterify ammonium lactate to the lactate ester;(c) recovering purified lactic acid; and (d) vaporizing the lactic acid and catalytically converting to acrylic acid ester. The esterification in step (b) is carried out using a single stage reactor. However, since esterification is an equilibrium reaction, the use of a single stage reactor limits the conversion of the carboxylic acid ammonium salt into the ester. Indeed, generation of water by the reaction in the liquid phase biocks progress of conversion beyond the point of reaction equilibrium. Then, a pure product free of substantial amounts of reactants and water is difficult to obtain. The final composition merely consists of a mixture of reactants and products, including water. In the case of esterification with lower molecular weight alcohols such as methanol or ethanol, technologies have been developed to overcome the limitation by employing toxic solvents such as halogenated solvents and benzene (Gui-Sheng Zhang, "Fe2(SO4)3.xH2O Catalytic Esterification of Aliphatic Carboxylic Acids with Alcohols," Synthetic Communications, 28(7), 1159-1162, (1998)).
These hydrophobic solvents generate an organic phase where the reaction takes place and partitions the water away from the reaction thereby pushing the equilibrium in favour of higher conversion and yield. However, additional steps that include catalyst quenching, washing, and distillation steps, not withstanding mandated technologies necessary to reclaim and reuse toxic solvents, are necessary to isolate the product. Overall, the complexity of the process presents several drawbacks including low yield and high capital.
US Patent 5,453,365 discloses an integrated process for the production of lactate esters comprising: (a) adding an alkaline earth metal carbonate or bicarbonate to neutralize a fermentation broth; (b) addition of CO2 and NH3 to precipitate alkaline earth metal carbonates and produce ammonium lactate;
and (c) esterifying ammonium lactate with an alcohol. The esterification is carried out using standard conditions and preferably in the absence of catalyst.
Thus, there is still a need for a new process helping make biobased carboxylic acids a more economically and technically attractive feedstock for the production of esters.
There is a need for a process, wherein conversion of the carboxylic acid salt, regeneration of base values for recycling, and substantially, concentration of the broth, and separation and purification of the ester are conducted in a single step.
There is a need for a process producing esters of carboxylic acid directly from the carboxylic acid salt broth which circumvents the necessity to produce the intermediate acid.
There is a need for a process producing esters which are inherently purer compared to their corresponding acids and as a result are more compatible with catalytic processes used to produce valuable chemicals, such as BDO, THF, GBL, polybutylene succinate (PBS) and dialkyl maleate.
There is a need for a process producing industrial-grade esters of dicarboxylic acids which will be used to produce higher grade polymers 5 compared to that produced by corresponding industrial-grade dicarboxylic acids.
SUMMARY OF THE INVENTION
The present invention aims to provide a new process for direct production of esters of carboxylic acid from the corresponding salts of the carboxylic acid which are obtained by fermentation, thereby avoiding potentially costly separation and purification steps associated with production of the free carboxylic acid.
This object is achieved by the process of the present invention.
The present invention thus provides a process for producing an ester of carboxylic acid from a fermented broth comprising in one step providing a fermented broth containing at least one carboxylic acid salt and in another step obtaining the ester of carboxylic acid by subjecting the carboxylic acid salt to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst.
The present invention also provides a process as described hereinabove, wherein the ester of carboxylic acid is further subjected to a catalytic hydrogenation reaction.
The present invention further provides a process as described hereinabove, wherein the ester of carboxylic acid is further subjected to a catalytic oxidative dehydrogenation reaction.
The present invention also concerns a process for producing dialkyl succinate from a fermented broth. The process comprises in one step providing a fermentable broth containing a carbohydrate source. The following step comprises subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NHs to obtain a fermented broth containing diammonium succinate. Then, the diammonium succinate contained in the fermented broth is concentrated using vacuum evaporation.
Further, the diammonium succinate is subjected to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinate.
The present invention also encompasses a process for producing 1,4-butanediol (BDO), tetrahydrofuran (THF), and gamma-butyrolactone (GBL) from a fermented broth. The process comprises in one step providing a fermentable broth containing a carbohydrate source. The following step comprises subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NH3 to obtain a fermented broth containing diammonium succinate. Then, the diammonium succinate contained in the fermented broth is concentrated using vacuum evaporation. In a subsequent step, the diammonium succinate is subjected to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinate. Further, the dialkyl succinate is subjected to a catalytic hydrogenation reaction to form BDO, THF and/or GBL.
The present invention further provides a process for producing dialkyl maleate from a fermented broth. The process comprises in one step providing a fermentable broth containing a carbohydrate source. The following step comprises subjecting the fermentable broth to an anaerobic, fermentation in the presence of COZ and NH3 to obtain a fermented broth containing diammonium succinate. Then, the diammonium succinate contained in the fermented broth is concentrated using vacuum evaporation.
In a subsequent step, the diammonium succinate is subjected to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinate.
Further, the dialkyl succinate is subjected to a catalytic oxidative dehydrogenation reaction to form dialkyl maleate.
In a preferred embodiment, the alkanol is methanol, ethanol, propanol, butanol, or amyl alcohol.
DESCRIPTION OF THE FIGURES
Fig. 1 is a schematic representation of the different steps in a preferred embodiment of the process according to the invention.
Fig. 2 represents a block flow diagram of the experimental setup for carrying out a preferred embodiment of the process according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a novel process for direct production of esters of carboxylic acids from a fermentable carbohydrate source (sugars).
Definitions The expression fermentable broth according to the invention means a broth containing one or more carbohydrates or sugars which are capable of providing a fermented broth containing at least one carboxylic acid salt upon fermentation by a carboxylic acid producing organism. In a preferred embodiment, the fermentation is anaerobic. For fermentation technologies targeted for chemical industries that are typically classified as "high volume/low value" processes, the fermentable broth can be formuiated using inexpensive agricultural and forestry waste/byproducts such as corn steep liquor/solids, which contain nutrients in numerous and significant proportions.
Some elemental and nutritional fortification of the media using small amounts of inorganic salts and nutrients may be necessary to satisfy physiological requirements of specific microorganisms. Generally, the most productive and economical combination that will satisfy requirements for cell biomass and metabolite production, energy requirements, as well as fermentability requirements are considered in formulating the fermentable broth.
Carbohydrates utilized in fermentable broths are numerous. Conventional carbohydrates include glucose, fructose, and sucrose. The latter is a disaccharide glucoside, which is utilized in a number of fermentation processes including the production of proteins, ethanol, organic acids, and amino acids. Hydrolyzed structural polysaccharides from plant biomass are considered as next generation substrates for fermentable broths. Hydrolysis of cellulose and hemicelluloses provide several hexoses (glucose and mannose) and pentoses (xylose and arabinose) for fermentation. Batch fermentations may utilize in excess of 100 g/L of substrate and continuous or fed-batch fermentation may utilize 0.5 - 4.0 g/Uhr of substrate.
A carboxylic acid producing organism according to the invention means an organism capable of producing a carboxylic acid from a carbohydrate contained in a fermentable broth. For example, the organism may be Aspergillus niger, Corynebacterium glutamicum (also called Brevibacterium flafum), Escherichia coli, Enterococcus faecalis, Veillonella parvula, Actinobacillus succinogenes, Mannheimia succiniciproducens, Anaerobiospirillum succiniciproducens, Paecilomyces varioti, Saccharomyces cerevisiae, Bacteroides fragilis, Bacteroides ruminicola, Bacteroides amylophilus, or any other organism capable of producing carboxylic acids, or a mixture thereof. Preferably, the organism is the microorganism E. coli.
The carboxylic acid salt according the invention is a salt of a saturated carboxylic acid which is produced by a microorganism by fermentation of carbohydrates contained in a fermentable broth. The carboxylic acid salt may be one of a monocarboxylic acid, a dicarboxylic acid salt or tricarboxylic acid.
However, the invention also encompasses a mixture of such carboxylic acid salts. For example, the salt may be a salt of a dicarboxylic acid such as a salt of the succinic acid. The salt is obtained in the presence of a base, for example an amine. The salt may also be a salt of potassium, sodium, calcium, magnesium or ammonium. Advantageously, the salt is an ammonium salt. More preferably, the carboxylic acid salt is diammonium succinate. The diammonium succinate may advantageously be present in admixture with ammonium acetate.
The term alkanol according to the invention means an alkyl alcohol wherein the alkyl group may be linear or branched alkyl containing from 1 to 12 carbon atoms. Preferably, the alkyl group contains 1 to 5 carbon atoms. More preferably, the alkanol is methanol, ethanol, propanol, butanol, or amyl alcohol. A preferred aikanol is ethanol or methanol.
In the context of the invention, the reactive distillation refers to the step of the process wherein reaction (esterification) and substantially, concentration of the feed stream, separation of the product, and purification of the product are conducted in a single step. Reactive distillation is particularly suitable for equilibrium controlled reactions such as esterification. Utilization of reactive distillation enables to obtain pure products in spite of the equilibrium.
Furthermore, exothermicity of the reaction aids distillation, which is an inherent advantage of the method. The reactive distillation allows high yield and purity.
The term about is used herein in connection with the quantities, ranges, percentages or ratios of the various products, to express that such quantities, ranges, percentages or ratios are not of the exact number recited herein but may be slightly above or under this number due to measurement and/or calculation errors.
Description of preferred embodiments of the invention The present invention provides an integrated process for direct production of esters of carboxylic acids from a fermentable carbohydrate source (sugars).
Referring to fig. 1, a schematic representation of the conceived process is provided. The process is depicted with reference to the biobased succinic acid value chain and fermentation of sugars using E. coli. However, the principles are applicable to other fermentable carboxylic acids including 5 monocarboxylic, dicarboxylic or tricarboxylic acids. Examples of dicarboxylic acids other than succinic acid include glutaric, adipic, azelaic, or sebacic acids. An example of a tricarboxylic acid is citric acid. Moreover, the process is also applicable to microorganisms other than E. coli such as for example Aspergillus niger, Corynebacterium glutamicum (also called Brevibacterium 10 flafum), Enterococcus faecalis, Veillonella parvula, Actinobacillus succinogenes, Mannheimia succiniciproducens, Anaerobiospirillum succiniciproducens, Paecilomyces varioti, Saccharomyces cerevisiae, Bacteroides fragilis, Bacteroides ruminicola, Bacteroides amylophilus, or any other organism capable of producing carboxylic acids, or a mixture thereof.
The first step of the process (I) is the production of the carboxylic acid salt. In the preferred embodiment depicted in Fig. 1, step (I) produces diammonium succinate via anaerobic E. coli fermentation of a broth containing the carbohydrate source (sugars). The anaerobic fermentation requires CO2 as a feedstock and NH3 as neutralizing agent. The fermentation is carried out at neutral pH conditions resulting in relatively dilute succinate salt broth. The fermentation conditions are otherwise standard conditions known in the art It is worth noting that even though ammonium salts are preferably produced by the fermentation, other salts including potassium, sodium, calcium and magnesium salts could be produced in this manner.
As seen in Fig. 1, the process provides a method for providing CO2 and NH3 to the fermentation step (I) by integrating the downstream pressurized reactive distillation step (III) wherein the said gasses are produced. The C02 is used as a feedstock for the anaerobic fermentation and simultaneously, NH3 is used to neutralize the fermented carboxylic acid.
Conversion of the salt to the acid and its purification involve several unit operations that could potentially diminish the economic viability of biobased succinic acid as a platform chemical. Furthermore, acidification and purification based processes may not provide economically viable high-grade succinic acid suitable for catalytic processes such as hydrogenation and oxidative dehydrogenation. Hydrogenation products of succinic acid include 1,4-butanediol (BDO), tetrahydrofuran (THF), and gamma-butyrolactone (GBL), which are large volume commodity chemicals. Catalytic oxidative dehydrogenation of succinic acid produces maleic anhydride, which has a demand approaching 1.5 billion kg, worldwide.
The catalysts used for hydrogenation and oxidative dehydrogenation are highly susceptible to deactivation in the presence of trace impurities.
Furthermore, current biobased succinic acid production technologies produce molar equivalents of the conjugate salt (for example, ammonium sulfate) that has to be disposed at considerable expense or further processed to regenerate the acid and base values for reuse within the process. Although electrodialysis, particularly bipolar electrodialysis, has been proposed as a means to convert the carboxylic acid salt to its acid form while simultaneously producing the base values for recycling, the energy consumption can be economically prohibitive.
Processes for the production of esters of carboxylic acids from fermentable broth, avoiding the use of the free carboxylic acid are disclosed in the literature. For example, WO 2007/116005 Al discloses a process for the production of polycarboxylic alkyl esters from aqueous solutions of the ammonium salt of the polycarboxylic acid by reactive distillation and an integrated method for hydrogenating the polycarboxylic alkyl ester. The esterification step is carried out using either heterogeneous or homogenous catalysis. An example of heterogeneous catalyst is an acidic ion exchanger catalyst which is fixed on or in column fittings. However, such structured catalysts are extremely susceptible to impurities, particularly numerous ionic salts that are abundant in fermentation broths. Examples of homogeneous catalysts include p-toluene sulfonic acid or methane sulfonic acid. Such catalysts are added to the aqueous solution of the ammonium salt of the carboxylic acid. However, such catalysts have to be used in significant concentrations and subsequently recovered from the product for recycling.
The catalysts recovery may not be trivial, and the document does not teach any method for the catalysts recovery.
US Patent No. 5,252,473 discloses an integrated process for the production of esters of acrylic acid comprising: (a) fermenting carbohydrate material with a lactic acid producing organism in the presence of NH3 to produce ammonium lactate;(b) combining the ammonium lactate with alcohol and an effective catalyzing amount of CO2 in a conventional single-stage esterification process to catalytically esterify ammonium lactate to the lactate ester;(c) recovering purified lactic acid; and (d) vaporizing the lactic acid and catalytically converting to acrylic acid ester. The esterification in step (b) is carried out using a single stage reactor. However, since esterification is an equilibrium reaction, the use of a single stage reactor limits the conversion of the carboxylic acid ammonium salt into the ester. Indeed, generation of water by the reaction in the liquid phase biocks progress of conversion beyond the point of reaction equilibrium. Then, a pure product free of substantial amounts of reactants and water is difficult to obtain. The final composition merely consists of a mixture of reactants and products, including water. In the case of esterification with lower molecular weight alcohols such as methanol or ethanol, technologies have been developed to overcome the limitation by employing toxic solvents such as halogenated solvents and benzene (Gui-Sheng Zhang, "Fe2(SO4)3.xH2O Catalytic Esterification of Aliphatic Carboxylic Acids with Alcohols," Synthetic Communications, 28(7), 1159-1162, (1998)).
These hydrophobic solvents generate an organic phase where the reaction takes place and partitions the water away from the reaction thereby pushing the equilibrium in favour of higher conversion and yield. However, additional steps that include catalyst quenching, washing, and distillation steps, not withstanding mandated technologies necessary to reclaim and reuse toxic solvents, are necessary to isolate the product. Overall, the complexity of the process presents several drawbacks including low yield and high capital.
US Patent 5,453,365 discloses an integrated process for the production of lactate esters comprising: (a) adding an alkaline earth metal carbonate or bicarbonate to neutralize a fermentation broth; (b) addition of CO2 and NH3 to precipitate alkaline earth metal carbonates and produce ammonium lactate;
and (c) esterifying ammonium lactate with an alcohol. The esterification is carried out using standard conditions and preferably in the absence of catalyst.
Thus, there is still a need for a new process helping make biobased carboxylic acids a more economically and technically attractive feedstock for the production of esters.
There is a need for a process, wherein conversion of the carboxylic acid salt, regeneration of base values for recycling, and substantially, concentration of the broth, and separation and purification of the ester are conducted in a single step.
There is a need for a process producing esters of carboxylic acid directly from the carboxylic acid salt broth which circumvents the necessity to produce the intermediate acid.
There is a need for a process producing esters which are inherently purer compared to their corresponding acids and as a result are more compatible with catalytic processes used to produce valuable chemicals, such as BDO, THF, GBL, polybutylene succinate (PBS) and dialkyl maleate.
There is a need for a process producing industrial-grade esters of dicarboxylic acids which will be used to produce higher grade polymers 5 compared to that produced by corresponding industrial-grade dicarboxylic acids.
SUMMARY OF THE INVENTION
The present invention aims to provide a new process for direct production of esters of carboxylic acid from the corresponding salts of the carboxylic acid which are obtained by fermentation, thereby avoiding potentially costly separation and purification steps associated with production of the free carboxylic acid.
This object is achieved by the process of the present invention.
The present invention thus provides a process for producing an ester of carboxylic acid from a fermented broth comprising in one step providing a fermented broth containing at least one carboxylic acid salt and in another step obtaining the ester of carboxylic acid by subjecting the carboxylic acid salt to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst.
The present invention also provides a process as described hereinabove, wherein the ester of carboxylic acid is further subjected to a catalytic hydrogenation reaction.
The present invention further provides a process as described hereinabove, wherein the ester of carboxylic acid is further subjected to a catalytic oxidative dehydrogenation reaction.
The present invention also concerns a process for producing dialkyl succinate from a fermented broth. The process comprises in one step providing a fermentable broth containing a carbohydrate source. The following step comprises subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NHs to obtain a fermented broth containing diammonium succinate. Then, the diammonium succinate contained in the fermented broth is concentrated using vacuum evaporation.
Further, the diammonium succinate is subjected to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinate.
The present invention also encompasses a process for producing 1,4-butanediol (BDO), tetrahydrofuran (THF), and gamma-butyrolactone (GBL) from a fermented broth. The process comprises in one step providing a fermentable broth containing a carbohydrate source. The following step comprises subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NH3 to obtain a fermented broth containing diammonium succinate. Then, the diammonium succinate contained in the fermented broth is concentrated using vacuum evaporation. In a subsequent step, the diammonium succinate is subjected to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinate. Further, the dialkyl succinate is subjected to a catalytic hydrogenation reaction to form BDO, THF and/or GBL.
The present invention further provides a process for producing dialkyl maleate from a fermented broth. The process comprises in one step providing a fermentable broth containing a carbohydrate source. The following step comprises subjecting the fermentable broth to an anaerobic, fermentation in the presence of COZ and NH3 to obtain a fermented broth containing diammonium succinate. Then, the diammonium succinate contained in the fermented broth is concentrated using vacuum evaporation.
In a subsequent step, the diammonium succinate is subjected to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinate.
Further, the dialkyl succinate is subjected to a catalytic oxidative dehydrogenation reaction to form dialkyl maleate.
In a preferred embodiment, the alkanol is methanol, ethanol, propanol, butanol, or amyl alcohol.
DESCRIPTION OF THE FIGURES
Fig. 1 is a schematic representation of the different steps in a preferred embodiment of the process according to the invention.
Fig. 2 represents a block flow diagram of the experimental setup for carrying out a preferred embodiment of the process according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a novel process for direct production of esters of carboxylic acids from a fermentable carbohydrate source (sugars).
Definitions The expression fermentable broth according to the invention means a broth containing one or more carbohydrates or sugars which are capable of providing a fermented broth containing at least one carboxylic acid salt upon fermentation by a carboxylic acid producing organism. In a preferred embodiment, the fermentation is anaerobic. For fermentation technologies targeted for chemical industries that are typically classified as "high volume/low value" processes, the fermentable broth can be formuiated using inexpensive agricultural and forestry waste/byproducts such as corn steep liquor/solids, which contain nutrients in numerous and significant proportions.
Some elemental and nutritional fortification of the media using small amounts of inorganic salts and nutrients may be necessary to satisfy physiological requirements of specific microorganisms. Generally, the most productive and economical combination that will satisfy requirements for cell biomass and metabolite production, energy requirements, as well as fermentability requirements are considered in formulating the fermentable broth.
Carbohydrates utilized in fermentable broths are numerous. Conventional carbohydrates include glucose, fructose, and sucrose. The latter is a disaccharide glucoside, which is utilized in a number of fermentation processes including the production of proteins, ethanol, organic acids, and amino acids. Hydrolyzed structural polysaccharides from plant biomass are considered as next generation substrates for fermentable broths. Hydrolysis of cellulose and hemicelluloses provide several hexoses (glucose and mannose) and pentoses (xylose and arabinose) for fermentation. Batch fermentations may utilize in excess of 100 g/L of substrate and continuous or fed-batch fermentation may utilize 0.5 - 4.0 g/Uhr of substrate.
A carboxylic acid producing organism according to the invention means an organism capable of producing a carboxylic acid from a carbohydrate contained in a fermentable broth. For example, the organism may be Aspergillus niger, Corynebacterium glutamicum (also called Brevibacterium flafum), Escherichia coli, Enterococcus faecalis, Veillonella parvula, Actinobacillus succinogenes, Mannheimia succiniciproducens, Anaerobiospirillum succiniciproducens, Paecilomyces varioti, Saccharomyces cerevisiae, Bacteroides fragilis, Bacteroides ruminicola, Bacteroides amylophilus, or any other organism capable of producing carboxylic acids, or a mixture thereof. Preferably, the organism is the microorganism E. coli.
The carboxylic acid salt according the invention is a salt of a saturated carboxylic acid which is produced by a microorganism by fermentation of carbohydrates contained in a fermentable broth. The carboxylic acid salt may be one of a monocarboxylic acid, a dicarboxylic acid salt or tricarboxylic acid.
However, the invention also encompasses a mixture of such carboxylic acid salts. For example, the salt may be a salt of a dicarboxylic acid such as a salt of the succinic acid. The salt is obtained in the presence of a base, for example an amine. The salt may also be a salt of potassium, sodium, calcium, magnesium or ammonium. Advantageously, the salt is an ammonium salt. More preferably, the carboxylic acid salt is diammonium succinate. The diammonium succinate may advantageously be present in admixture with ammonium acetate.
The term alkanol according to the invention means an alkyl alcohol wherein the alkyl group may be linear or branched alkyl containing from 1 to 12 carbon atoms. Preferably, the alkyl group contains 1 to 5 carbon atoms. More preferably, the alkanol is methanol, ethanol, propanol, butanol, or amyl alcohol. A preferred aikanol is ethanol or methanol.
In the context of the invention, the reactive distillation refers to the step of the process wherein reaction (esterification) and substantially, concentration of the feed stream, separation of the product, and purification of the product are conducted in a single step. Reactive distillation is particularly suitable for equilibrium controlled reactions such as esterification. Utilization of reactive distillation enables to obtain pure products in spite of the equilibrium.
Furthermore, exothermicity of the reaction aids distillation, which is an inherent advantage of the method. The reactive distillation allows high yield and purity.
The term about is used herein in connection with the quantities, ranges, percentages or ratios of the various products, to express that such quantities, ranges, percentages or ratios are not of the exact number recited herein but may be slightly above or under this number due to measurement and/or calculation errors.
Description of preferred embodiments of the invention The present invention provides an integrated process for direct production of esters of carboxylic acids from a fermentable carbohydrate source (sugars).
Referring to fig. 1, a schematic representation of the conceived process is provided. The process is depicted with reference to the biobased succinic acid value chain and fermentation of sugars using E. coli. However, the principles are applicable to other fermentable carboxylic acids including 5 monocarboxylic, dicarboxylic or tricarboxylic acids. Examples of dicarboxylic acids other than succinic acid include glutaric, adipic, azelaic, or sebacic acids. An example of a tricarboxylic acid is citric acid. Moreover, the process is also applicable to microorganisms other than E. coli such as for example Aspergillus niger, Corynebacterium glutamicum (also called Brevibacterium 10 flafum), Enterococcus faecalis, Veillonella parvula, Actinobacillus succinogenes, Mannheimia succiniciproducens, Anaerobiospirillum succiniciproducens, Paecilomyces varioti, Saccharomyces cerevisiae, Bacteroides fragilis, Bacteroides ruminicola, Bacteroides amylophilus, or any other organism capable of producing carboxylic acids, or a mixture thereof.
The first step of the process (I) is the production of the carboxylic acid salt. In the preferred embodiment depicted in Fig. 1, step (I) produces diammonium succinate via anaerobic E. coli fermentation of a broth containing the carbohydrate source (sugars). The anaerobic fermentation requires CO2 as a feedstock and NH3 as neutralizing agent. The fermentation is carried out at neutral pH conditions resulting in relatively dilute succinate salt broth. The fermentation conditions are otherwise standard conditions known in the art It is worth noting that even though ammonium salts are preferably produced by the fermentation, other salts including potassium, sodium, calcium and magnesium salts could be produced in this manner.
As seen in Fig. 1, the process provides a method for providing CO2 and NH3 to the fermentation step (I) by integrating the downstream pressurized reactive distillation step (III) wherein the said gasses are produced. The C02 is used as a feedstock for the anaerobic fermentation and simultaneously, NH3 is used to neutralize the fermented carboxylic acid.
The following step is the partial concentration step (II) which is usually conducted under vacuum evaporation. In this step, ammonium succinate is concentrated prior to esterification step (III). At laboratory scale, concentration of the ammonium succinate broth can be conducted using a standard rotary evaporator operating at about 50-100 C and appropriate vacuum. In a commercial manufacturing operation, pre-concentration is advantageously conducted using a multi effect evaporator leading to substantial energy savings compared to conducting the concentration during esterification under esterification conditions. Furthermore, the concentrated broth will improve conversion yield and rate of the succinate salt to the ester reaction. The concentration of the concentrate with respect to ammonium succinate will be in the range of about 20 % - 60 % by weight depending on desired feed conditions and the temperature for subsequent esterification. It also may be necessary to remove any resulting precipitate using standard filtration techniques or centrifugation.
The next step of the process is the pressurized reactive distillation of esters from the carboxylic acid salts. In the preferred embodiment depicted in Fig.
1, step (III) corresponds to the esterification of diammonium succinate, and possibly by-product salt present in the concentrated broth, in the presence of ethanol as the alkanol to get diethyl succcinate. Acid by-products of the fermentation step may include formic, lactic, acetic, or propionic acid. Of course, alkanois other than ethanol could be used for the esterification step, such as methanol, propanol, butanol or amyl alcohol. The esterification is carried out at relatively high pressure and temperature using COZ as a catalyst. For example, the temperature may range from about 100 C to about 200 C and the pressure from about 1000 psig to about 2000 psig. As shown in Fig. 1, ethanol is added to the reactive distillation as an azeotropic solution with water. However, ethanol could also be added as dry ethanol.
Diethyl succinate obtained from reactive distillation esterification is further conventionally distilled for further purification (IV). All condensable liquids exiting the reactive distillation including ethanol, water and volatile esters from fermentation by-products (e.g. ethyl acetate), are delivered for separation using conventional distillation (V). Ethanol alone or azeotropic ethanol-water solution may be fed back to the reactive distillation step (III).
The process of the invention may further integrate catalytic hydrogenation of the succinate ester. As depicted in Fig. 1, the crude succinate ester exiting the reactive distillation is further distilled for purification. Then, purified succinate ester can be catalytically hydrogenated in step (VI). In the case of diethyl succinate, the hydrogenation will produce 1,4-butanediol (BDO), tetrahydrofuran (THF) and ior gamma-butyrolactone (GBL). Of course, if the dicarboxylic acid produced from the fermentable broth is glutaric acid or adipic acid the process will produce 1,5-pentanediol or 1,6-hexanediol, respectively. Even though Fig. 1 indicates that the catalytic hydrogenation is carried out using purified diethyl succinate, it could also be possible to integrate the catalytic hydrogenation step directly after the esterification step using crude succinate ester. Reactor assemblies used for ester hydrogenation are well known to those familiar with the art. They are typically tubular reactors constructed with 316 Stainless Steel capable of withstanding high temperatures and pressures. Numerous catalysts and supports are employed for hydrogenation.5 The appropriate choice for the catalyst and support combination for succinate ester hydrogenation is well known to those familiar with the art. Typically, the ester feed can be diluted with the corresponding alkanol and consequently the feed compositions could range from about 0 to about 50 % of alkanol. The hydrogen:ester feed ratio may vary between about 100:1 and about 300:1.
The process of the invention may also integrate catalytic oxidative dehydrogenation of the succinate ester. As depicted in Fig. 1, the crude succinate ester exiting the reactive distillation is further distilled for purification. Then, purified succinate ester can be subjected to a catalytic oxidative dehydrogenated in step (VII). In the case of diethyl succinate, the dehydrogenation will produce diethyl maleate. However, other unsaturated dicarboxylic acids/esters may be obtained from oxidative dehydrogenation of the homologous series of saturated dicarboxylic acids/esters.
Even though Fig. 1 indicates that the catalytic oxidative dehydrogenation is carried out using purified diethyl succinate, it could also be possible to integrate the catalytic dehydrogenation step directly after the esterification step using crude succinate ester. Reactor assemblies used for ester dehydrogenation are well known to those familiar with the art and generally similar to that used for hydrogenation. They are typically tubular reactors constructed with 316 Stainless Steel capable of withstanding high temperatures and pressures. The reactors are constructed with temperature and pressure regulation capabilities in order to affect the dehydrogenation equilibrium such that the desired product can be obtained in high conversion and yield. It is generally known that oxidative dehydrogenation is favored over conventional dehydrogenation since the presence of oxygen positively impacts the thermodynamic equilibrium of dehydrogenation.6 Typically the quantity of ester fed to the reactor can range from about 0.5 to about 1.5 grams of ester per gram of catalysts per hour. The ester feed can be diluted with the corresponding alkanol and consequently the feed compositions could range from about 0 to about 50 % of alkanol. Oxygen is fed using high pressure regulators and the oxygen:ester molar feed ratio will vary between about 1:1 to about 100:1. For commercial operation, air could substitute for pure oxygen making the process more economical.
Advantages of the process of the present invention over known techniques Both conventional single-stage esterification and esterification via conventional reactive distillation require a carboxylic acid feed stream that is in the corresponding free acid form. Pre-conversion of the carboxylic acid salt to the free acid form using a mineral acid (for example, sulfuric acid) generates a molar quantity of the conjugate salt (ammonium sulfate in the case of conversion of diammonium succinate and ammonium acetate). Such processes are encumbered by the necessity to either dispose the conjugate salt at a cost to the process or employ other means such as thermal cracking or electrodialysis to regenerate acid and base values. On the contrary, the process of the present invention does not require the use of a mineral acid (since the intermediate step of generating the carboxylate in the free acid form is avoided) and consequently the generation of the conjugate salt is avoided. Furthermore, the process of the present invention generates the base values necessary for the fermentation in the pressurized reactive distillation step and can be provided by direct integration.
Conventional reactive distillation requires expensive structured catalysts for esterification. These catalysts, are highly sensitive to trace impurities and have a short and a finite life cycle. Therefore, pre-purification of the carboxylic acid is an imperative making such processes less attractive.
Fermentation broths are inherently laden with numerous ionic and biogenic impurities and therefore pre-purification can be a severe cost burden. The process of the present invention is catalyzed by gaseous CO2 under pressure, which is not affected by impurities in the feed stream. In addition, CO2 will help drive out NH3, thereby minimizing the chances for amido ester formation. Furthermore, the CO2 is not exhausted, rather used as a feedstock for the anaerobic fermentation by direct integration of the two unit operations.
In summary, the present process provides:
1- generally, a method for full integration of ammonium carboxylate direct esterification and production of ammonium carboxylate via fermentation of sugars;
2- specifically, a method for full integration of diammonium succinate direct esterification and production of diammonium succinate via fermentation of sugars;
3- generally, a method for direct production of aikyl carboxylate via pressurized reactive distillation of the corresponding ammonium carboxylate and an alkanol;
4- specifically, a method for direct production of dialkyl succinate via 5 pressurized reactive distillation of diammonium succinate and an alkanol;
5- a method for using CO2 as a catalyst for esterification in a pressurized reactive distillation column;
6- a method for producing the said esters without using structured 10 catalysts;
7- a method for producing the said esters without using soluble catalysts.
8- generally, a fully integrated method for producing alkyl carboxylate from fermentable sugars;
9- specifically, a fully integrated method for producing dialkyl succinate 15 from fermentable sugars;
10- a fully integrated method for separation of ester byproducts (for example, alkyl acetate), water, and the alkanol, wherein the latter is recycled as a feed stream for pressurized reactive distillation of alkyl carboxylates;
11- a fully integrated method for producing hydrogenation products such as glycols from dialkyl carboxylates;
12- a fully integrated method for producing dehydrogenation products such as unsaturated carboxylic acid esters from dialkyl carboxylates;
13- a fully integrated method for producing BDO, THF, and GBL via hydrogenation of dialkyl succinate;
14- a fully integrated method for producing dialkyl maleate via oxidative dehydrogenation of dialkyl succinate; and 15- a fully integrated bioprocess that does not generate low-value chemical products.
The next step of the process is the pressurized reactive distillation of esters from the carboxylic acid salts. In the preferred embodiment depicted in Fig.
1, step (III) corresponds to the esterification of diammonium succinate, and possibly by-product salt present in the concentrated broth, in the presence of ethanol as the alkanol to get diethyl succcinate. Acid by-products of the fermentation step may include formic, lactic, acetic, or propionic acid. Of course, alkanois other than ethanol could be used for the esterification step, such as methanol, propanol, butanol or amyl alcohol. The esterification is carried out at relatively high pressure and temperature using COZ as a catalyst. For example, the temperature may range from about 100 C to about 200 C and the pressure from about 1000 psig to about 2000 psig. As shown in Fig. 1, ethanol is added to the reactive distillation as an azeotropic solution with water. However, ethanol could also be added as dry ethanol.
Diethyl succinate obtained from reactive distillation esterification is further conventionally distilled for further purification (IV). All condensable liquids exiting the reactive distillation including ethanol, water and volatile esters from fermentation by-products (e.g. ethyl acetate), are delivered for separation using conventional distillation (V). Ethanol alone or azeotropic ethanol-water solution may be fed back to the reactive distillation step (III).
The process of the invention may further integrate catalytic hydrogenation of the succinate ester. As depicted in Fig. 1, the crude succinate ester exiting the reactive distillation is further distilled for purification. Then, purified succinate ester can be catalytically hydrogenated in step (VI). In the case of diethyl succinate, the hydrogenation will produce 1,4-butanediol (BDO), tetrahydrofuran (THF) and ior gamma-butyrolactone (GBL). Of course, if the dicarboxylic acid produced from the fermentable broth is glutaric acid or adipic acid the process will produce 1,5-pentanediol or 1,6-hexanediol, respectively. Even though Fig. 1 indicates that the catalytic hydrogenation is carried out using purified diethyl succinate, it could also be possible to integrate the catalytic hydrogenation step directly after the esterification step using crude succinate ester. Reactor assemblies used for ester hydrogenation are well known to those familiar with the art. They are typically tubular reactors constructed with 316 Stainless Steel capable of withstanding high temperatures and pressures. Numerous catalysts and supports are employed for hydrogenation.5 The appropriate choice for the catalyst and support combination for succinate ester hydrogenation is well known to those familiar with the art. Typically, the ester feed can be diluted with the corresponding alkanol and consequently the feed compositions could range from about 0 to about 50 % of alkanol. The hydrogen:ester feed ratio may vary between about 100:1 and about 300:1.
The process of the invention may also integrate catalytic oxidative dehydrogenation of the succinate ester. As depicted in Fig. 1, the crude succinate ester exiting the reactive distillation is further distilled for purification. Then, purified succinate ester can be subjected to a catalytic oxidative dehydrogenated in step (VII). In the case of diethyl succinate, the dehydrogenation will produce diethyl maleate. However, other unsaturated dicarboxylic acids/esters may be obtained from oxidative dehydrogenation of the homologous series of saturated dicarboxylic acids/esters.
Even though Fig. 1 indicates that the catalytic oxidative dehydrogenation is carried out using purified diethyl succinate, it could also be possible to integrate the catalytic dehydrogenation step directly after the esterification step using crude succinate ester. Reactor assemblies used for ester dehydrogenation are well known to those familiar with the art and generally similar to that used for hydrogenation. They are typically tubular reactors constructed with 316 Stainless Steel capable of withstanding high temperatures and pressures. The reactors are constructed with temperature and pressure regulation capabilities in order to affect the dehydrogenation equilibrium such that the desired product can be obtained in high conversion and yield. It is generally known that oxidative dehydrogenation is favored over conventional dehydrogenation since the presence of oxygen positively impacts the thermodynamic equilibrium of dehydrogenation.6 Typically the quantity of ester fed to the reactor can range from about 0.5 to about 1.5 grams of ester per gram of catalysts per hour. The ester feed can be diluted with the corresponding alkanol and consequently the feed compositions could range from about 0 to about 50 % of alkanol. Oxygen is fed using high pressure regulators and the oxygen:ester molar feed ratio will vary between about 1:1 to about 100:1. For commercial operation, air could substitute for pure oxygen making the process more economical.
Advantages of the process of the present invention over known techniques Both conventional single-stage esterification and esterification via conventional reactive distillation require a carboxylic acid feed stream that is in the corresponding free acid form. Pre-conversion of the carboxylic acid salt to the free acid form using a mineral acid (for example, sulfuric acid) generates a molar quantity of the conjugate salt (ammonium sulfate in the case of conversion of diammonium succinate and ammonium acetate). Such processes are encumbered by the necessity to either dispose the conjugate salt at a cost to the process or employ other means such as thermal cracking or electrodialysis to regenerate acid and base values. On the contrary, the process of the present invention does not require the use of a mineral acid (since the intermediate step of generating the carboxylate in the free acid form is avoided) and consequently the generation of the conjugate salt is avoided. Furthermore, the process of the present invention generates the base values necessary for the fermentation in the pressurized reactive distillation step and can be provided by direct integration.
Conventional reactive distillation requires expensive structured catalysts for esterification. These catalysts, are highly sensitive to trace impurities and have a short and a finite life cycle. Therefore, pre-purification of the carboxylic acid is an imperative making such processes less attractive.
Fermentation broths are inherently laden with numerous ionic and biogenic impurities and therefore pre-purification can be a severe cost burden. The process of the present invention is catalyzed by gaseous CO2 under pressure, which is not affected by impurities in the feed stream. In addition, CO2 will help drive out NH3, thereby minimizing the chances for amido ester formation. Furthermore, the CO2 is not exhausted, rather used as a feedstock for the anaerobic fermentation by direct integration of the two unit operations.
In summary, the present process provides:
1- generally, a method for full integration of ammonium carboxylate direct esterification and production of ammonium carboxylate via fermentation of sugars;
2- specifically, a method for full integration of diammonium succinate direct esterification and production of diammonium succinate via fermentation of sugars;
3- generally, a method for direct production of aikyl carboxylate via pressurized reactive distillation of the corresponding ammonium carboxylate and an alkanol;
4- specifically, a method for direct production of dialkyl succinate via 5 pressurized reactive distillation of diammonium succinate and an alkanol;
5- a method for using CO2 as a catalyst for esterification in a pressurized reactive distillation column;
6- a method for producing the said esters without using structured 10 catalysts;
7- a method for producing the said esters without using soluble catalysts.
8- generally, a fully integrated method for producing alkyl carboxylate from fermentable sugars;
9- specifically, a fully integrated method for producing dialkyl succinate 15 from fermentable sugars;
10- a fully integrated method for separation of ester byproducts (for example, alkyl acetate), water, and the alkanol, wherein the latter is recycled as a feed stream for pressurized reactive distillation of alkyl carboxylates;
11- a fully integrated method for producing hydrogenation products such as glycols from dialkyl carboxylates;
12- a fully integrated method for producing dehydrogenation products such as unsaturated carboxylic acid esters from dialkyl carboxylates;
13- a fully integrated method for producing BDO, THF, and GBL via hydrogenation of dialkyl succinate;
14- a fully integrated method for producing dialkyl maleate via oxidative dehydrogenation of dialkyl succinate; and 15- a fully integrated bioprocess that does not generate low-value chemical products.
Experimental protocol The experimental protocol for carrying out the process of the present invention is provided by referring to the block flow diagram of the experimental setup in Fig. 2.
Concentration: Fermentation of suitable carbohydrates by commercially viable succinic acid producing organisms at pH neutral conditions results in a relatively dilute succinate salt broth. Although, potassium, sodium, calcium, and magnesium slats of succinic acid can be produced in this manner, the preferred embodiment for the presently disclosed invention is ammonium succinate. It is desirable to concentrate the ammonium succinate broth prior to esterification. In a commercial manufacturing operation, pre-concentration can be conducted using a multi effect evaporator leading to substantial energy savings compared to conducting the concentration during esterification under esterification conditions. Furthermore, the concentrated broth will improve conversion yield and rate of the succinate salt to the ester reaction. The concentration of the concentrate with respect to ammonium succinate will be in the range of about 20% to about 60% by weight depending on desired feed conditions and the temperature for subsequent esterification. It may be necessary to remove any resulting precipitate using standard filtration techniques or centrifugation. At laboratory scale, concentration of the ammonium succinate broth can be conducted using a standard rotary evaporator operating at about 50 to about 100 C and appropriate vacuum.
The concentrate will be fed to the esterification column via the feed port labelled [1].
Esterification: The conceived process will produce diesters of succinic acid (particularly low molecular weight diesters such as dimethyl-, diethyl-, dipropyl-, dibutyl-, and diamyl succinate) directly from the ammonium succinate broth and circumvent the necessity to produce the intermediate acid.
The experimental esterification column is denoted as "A." It is anticipated that reactive distillation will be conducted at relatively high pressure and temperature. Temperature in the range of about 100 C to about 200 C and hot pressure in the range of about 1000 psig to about 2000 psig are anticipated (corresponding cold pressure will be in the range of about 250 to about 750 psig). Columns equipped with structured packing, a reboiler and a condenser suitable for operation under these conditions and appropriate for the application are well know to those familiar with the art. The column will have multiple feed ports and sample ports at varying column heights to aid process analysis and development.
The concentrated ammonium succinate broth will be fed to the esterification column via the feed port labelled [1]. It is well known in the art that the feed port height relative to the column is determined experimentally.
The desired low molecular weight alkanol (methanol, ethanol, propanol, butanol, amyl alcohol, etc.), dry or at azeotropic compositions, will be fed to the esterification column via the feed port labeled [2]. It is well known in the art that the feed port height relative to the column is determined experimentally.
The esterification will be catalyzed by vapor phase CO2 rising through the column. Therefore, high pressure CO2 will be introduced to the column at the bottom of the column via the port labelled as [3]. Vented CO2 from the fermentation step can be integrated with the feed for catalyzing esterification through intermediate storage. Whether the column is operated in a pressurized mode or not, CO2 will be continuously flushed from the column to help remove NH3. Retention of excessive NH3 in the column at envisioned operating conditions could lead to the formation of undesirable cyclic imides.
The non-condensable gases, primarily CO2 and NH3, will exit the column via the port labelled [4]. The formation of NH3 is illustrated by the following reaction:
H4NO-C-CHZ-CH2-C-O NH4 + 2 ROH-= RO-C-CH2-CHZ-C-OR + 2 NH3 + 2 H20 O O O O
The operation conditions of the protocol (temperature, pressure, and feed/product ratios and rates) are chosen to maximize the conversion of ammonium succinate and the yield of the alkyl ester, while minimizing the formation of undesirable compounds such as cyclic imides.
Unlike other catalytic systems proposed in prior art, CO2 will not be affected by biogenic impurities contained in fermentation broths and CO2 can be easily captured along with NH3 for reutilization for fermentation.
Back integration of COZ and NH3: The non-condensable gases, primarily, CO2 and NH3, exit the esterification column (A) via the port labelled [4]. NH3 can be captured for the neutralization of the fermentation broth and CO2 can be used as a feedstock for the fermentation. Two modes of operation for what is represented in Figure 2 as "D" are possible: (1) direct back integration of the two gasses; or (2) absorption of the two gasses in water to produce (NH4)2CO3. The technologies associated with both modes of operation are well known to those familiar with the art. The stream labelled [9], potentially through intermediate storage, leads to fermentation and supplies CO2 and NH3 in either their vapour phase or as an aqueous solution of (NH4)2C03.
The C02:NH3 ratio which is expected to be high at operating conditions will lead to excess CO2. The excess COZ can be captured and pressurized to supplement CO2 requirements for fermentation and delivered to the esterification step (A) for catalysis, thereby closing the CO2 process loop.
The CO2 loop can be replenished in an amount corresponding to that utilized in producing succinic acid during fermentation.
Concentration: Fermentation of suitable carbohydrates by commercially viable succinic acid producing organisms at pH neutral conditions results in a relatively dilute succinate salt broth. Although, potassium, sodium, calcium, and magnesium slats of succinic acid can be produced in this manner, the preferred embodiment for the presently disclosed invention is ammonium succinate. It is desirable to concentrate the ammonium succinate broth prior to esterification. In a commercial manufacturing operation, pre-concentration can be conducted using a multi effect evaporator leading to substantial energy savings compared to conducting the concentration during esterification under esterification conditions. Furthermore, the concentrated broth will improve conversion yield and rate of the succinate salt to the ester reaction. The concentration of the concentrate with respect to ammonium succinate will be in the range of about 20% to about 60% by weight depending on desired feed conditions and the temperature for subsequent esterification. It may be necessary to remove any resulting precipitate using standard filtration techniques or centrifugation. At laboratory scale, concentration of the ammonium succinate broth can be conducted using a standard rotary evaporator operating at about 50 to about 100 C and appropriate vacuum.
The concentrate will be fed to the esterification column via the feed port labelled [1].
Esterification: The conceived process will produce diesters of succinic acid (particularly low molecular weight diesters such as dimethyl-, diethyl-, dipropyl-, dibutyl-, and diamyl succinate) directly from the ammonium succinate broth and circumvent the necessity to produce the intermediate acid.
The experimental esterification column is denoted as "A." It is anticipated that reactive distillation will be conducted at relatively high pressure and temperature. Temperature in the range of about 100 C to about 200 C and hot pressure in the range of about 1000 psig to about 2000 psig are anticipated (corresponding cold pressure will be in the range of about 250 to about 750 psig). Columns equipped with structured packing, a reboiler and a condenser suitable for operation under these conditions and appropriate for the application are well know to those familiar with the art. The column will have multiple feed ports and sample ports at varying column heights to aid process analysis and development.
The concentrated ammonium succinate broth will be fed to the esterification column via the feed port labelled [1]. It is well known in the art that the feed port height relative to the column is determined experimentally.
The desired low molecular weight alkanol (methanol, ethanol, propanol, butanol, amyl alcohol, etc.), dry or at azeotropic compositions, will be fed to the esterification column via the feed port labeled [2]. It is well known in the art that the feed port height relative to the column is determined experimentally.
The esterification will be catalyzed by vapor phase CO2 rising through the column. Therefore, high pressure CO2 will be introduced to the column at the bottom of the column via the port labelled as [3]. Vented CO2 from the fermentation step can be integrated with the feed for catalyzing esterification through intermediate storage. Whether the column is operated in a pressurized mode or not, CO2 will be continuously flushed from the column to help remove NH3. Retention of excessive NH3 in the column at envisioned operating conditions could lead to the formation of undesirable cyclic imides.
The non-condensable gases, primarily CO2 and NH3, will exit the column via the port labelled [4]. The formation of NH3 is illustrated by the following reaction:
H4NO-C-CHZ-CH2-C-O NH4 + 2 ROH-= RO-C-CH2-CHZ-C-OR + 2 NH3 + 2 H20 O O O O
The operation conditions of the protocol (temperature, pressure, and feed/product ratios and rates) are chosen to maximize the conversion of ammonium succinate and the yield of the alkyl ester, while minimizing the formation of undesirable compounds such as cyclic imides.
Unlike other catalytic systems proposed in prior art, CO2 will not be affected by biogenic impurities contained in fermentation broths and CO2 can be easily captured along with NH3 for reutilization for fermentation.
Back integration of COZ and NH3: The non-condensable gases, primarily, CO2 and NH3, exit the esterification column (A) via the port labelled [4]. NH3 can be captured for the neutralization of the fermentation broth and CO2 can be used as a feedstock for the fermentation. Two modes of operation for what is represented in Figure 2 as "D" are possible: (1) direct back integration of the two gasses; or (2) absorption of the two gasses in water to produce (NH4)2CO3. The technologies associated with both modes of operation are well known to those familiar with the art. The stream labelled [9], potentially through intermediate storage, leads to fermentation and supplies CO2 and NH3 in either their vapour phase or as an aqueous solution of (NH4)2C03.
The C02:NH3 ratio which is expected to be high at operating conditions will lead to excess CO2. The excess COZ can be captured and pressurized to supplement CO2 requirements for fermentation and delivered to the esterification step (A) for catalysis, thereby closing the CO2 process loop.
The CO2 loop can be replenished in an amount corresponding to that utilized in producing succinic acid during fermentation.
Condensate: All condensable liquids that exit the top of the distillation column (A) including the alkanol, water, volatile esters (from fermentation by-products) are delivered for separation using conventionai vacuum distillation processes (B) via the stream labelled [5]. Conventional vacuum distillation processes suitable to practice the current invention are well known to those familiar with the art.
It is well known that all commercially viable succinic acid producing microorganisms, although optimized to produce succinic acid, produce varying levels of carboxylic acids such as acetic acid and formic acid.
Therefore, esters of these acids corresponding to the alkanol used for esterification will be delivered to "B" via [5]. A well designed serial distillation system will enable separation of the alcohol, water, and by-product ester(s).
The alkanol, with replenishment, can be fed back to the distillation column "A"
via the port identified as [2]. The water can be recycled for fermentation after treatment to remove any residual alkanol and esters. By-product esters such as ethyl acetate have commercial value and therefore contribute to overall process economics. The paths for both water and by-product esters are identified as stream [10] for illustration purposes.
It is well known in the art that in the case of ethanol, which form an azeotrope with water at an ethanol:water ratio of 95:5, the most economical approach would be to recycle the azeotropic composition. Both propanol and butanol also form azeotropes with water, but can be handled appropriately using techniques well known in the art.
The methodologies used to establish operating conditions to separate liquid mixtures containing water, alkanols, and esters via distillation, preferably vacuum, are well known to those familiar with the art.
Catalytic hydrogenation or oxidative dehydrogenation of the succinate ester: The crude dialkyl ester that is formed during esterification in "A" is collected as the bottom product and delivered for catalytic hydrogenation to ...._.-....~,,.....,._....._,~._._.__..,_.... .. . . . . ... .
"C" via [6]. Alternatively, the crude dialkyl ester is delivered for catalytic oxidative dehydrogenation to "C" via [6]. For illustrative purposes, both hydrogenation and dehydrogenation are identified as "C" in Figure 2.
It is well known in the art that if the alkanol used for esterification is one that 5 is low-boiling - methanol or ethanol - stream [6] will be substantially free of the alkanol. However, if the alkanol used for esterification is one that is relatively high-boiling - butanol - stream [6] may have a significant amount of the alkanol mixed with the corresponding ester.
It is also well known in the art that most commercial hydrogenation and 10 dehydrogenation technologies for esters are practiced in the vapour phase.
Therefore, the ester may be delivered for hydrogenation or dehydrogenation in "C" through an intermediate distillation step. The intermediate distiliation step will serve two purposes: (1) generate ester vapour and (2) separate the ester from ionic and biogenic impurities that are detrimental to hydrogenation 15 and dehydrogenation catalysts.
It is well known in the art that if the alkanol used for esterification is high-boiling, the overhead product of the intermediate distiliation step delivered via stream [6] for hydrogenation or dehydrogenation may have a significant amount of the alkanol mixed with the corresponding ester. Accordingly, the 20 alkanol is recovered and recycled after the hydrogenation or dehydrogenation step.
The methodologies used to establish operating conditions to purify an ester or a mixed ester and alkanol stream via distillation are well known to those familiar with the art.
Hydrogenation: Reactor assemblies used for ester hydrogenation are well known to those familiar with the art. They are typically tubular reactors constructed with 316 Stainless Steel capable of withstanding high temperatures and pressures. The reactors are constructed with temperature and pressure regulation capabilities in order to affect the hydrogenation equilibrium such that the desired product distribution can be obtained.
Numerous catalysts and supports are employed for hydrogenation.5 The appropriate choice for the catalyst and support combination for succinate ester hydrogenation is well known to those familiar with the art. Typically the ester feed to the reactor via stream [6] is measured as weight hourly space velocity, which can range from about 0.5 to about 1.5 grams of ester per gram of catalysts per hour. The ester feed can be diluted with the corresponding alkanol and consequently the feed compositions could range from about 0 to about 50 % of alkanol. Hydrogen is fed via stream [7] using high pressure regulators and the hydrogen:ester feed ratio will vary between about 100:1 and about 300:1. Reactors are equipped with apparatus for collection of both condensable and non-condensable products (stream [8]) for post reaction analysis using analytical techniques familiar to those practicing the art.
Dehydrogenation: Reactor assemblies used for ester dehydrogenation are well known to those familiar with the art and generally similar to that used for hydrogenation. They are typically tubular reactors constructed with 316 Stainless Steel capable of withstanding high temperatures and pressures.
The reactors are constructed with temperature and pressure regulation capabilities in order to affect the dehydrogenation equilibrium such that the desired product can be obtained in high conversion and yield. It is generally known that oxidative dehydrogenation is favored over conventional dehydrogenation since the presence of oxygen positively impacts the thermodynamic equilibrium of dehydrogenation.6 Numerous catalysts and supports are employed for dehydrogenation.s Typically the ester feed to the reactor via stream [6] is measured as weight hourly space velocity, which can range from about 0.5 to about 1.5 grams of ester per gram of catalysts per hour. The ester feed can be diluted with the corresponding alkanol and consequently the feed compositions could range from about 0 to about 50 %
of alkanol. Oxygen is fed via stream [7] using high pressure regulators and the oxygen:ester molar feed ratio will vary between about 1:1 to about 100:1.
It is well known that all commercially viable succinic acid producing microorganisms, although optimized to produce succinic acid, produce varying levels of carboxylic acids such as acetic acid and formic acid.
Therefore, esters of these acids corresponding to the alkanol used for esterification will be delivered to "B" via [5]. A well designed serial distillation system will enable separation of the alcohol, water, and by-product ester(s).
The alkanol, with replenishment, can be fed back to the distillation column "A"
via the port identified as [2]. The water can be recycled for fermentation after treatment to remove any residual alkanol and esters. By-product esters such as ethyl acetate have commercial value and therefore contribute to overall process economics. The paths for both water and by-product esters are identified as stream [10] for illustration purposes.
It is well known in the art that in the case of ethanol, which form an azeotrope with water at an ethanol:water ratio of 95:5, the most economical approach would be to recycle the azeotropic composition. Both propanol and butanol also form azeotropes with water, but can be handled appropriately using techniques well known in the art.
The methodologies used to establish operating conditions to separate liquid mixtures containing water, alkanols, and esters via distillation, preferably vacuum, are well known to those familiar with the art.
Catalytic hydrogenation or oxidative dehydrogenation of the succinate ester: The crude dialkyl ester that is formed during esterification in "A" is collected as the bottom product and delivered for catalytic hydrogenation to ...._.-....~,,.....,._....._,~._._.__..,_.... .. . . . . ... .
"C" via [6]. Alternatively, the crude dialkyl ester is delivered for catalytic oxidative dehydrogenation to "C" via [6]. For illustrative purposes, both hydrogenation and dehydrogenation are identified as "C" in Figure 2.
It is well known in the art that if the alkanol used for esterification is one that 5 is low-boiling - methanol or ethanol - stream [6] will be substantially free of the alkanol. However, if the alkanol used for esterification is one that is relatively high-boiling - butanol - stream [6] may have a significant amount of the alkanol mixed with the corresponding ester.
It is also well known in the art that most commercial hydrogenation and 10 dehydrogenation technologies for esters are practiced in the vapour phase.
Therefore, the ester may be delivered for hydrogenation or dehydrogenation in "C" through an intermediate distillation step. The intermediate distiliation step will serve two purposes: (1) generate ester vapour and (2) separate the ester from ionic and biogenic impurities that are detrimental to hydrogenation 15 and dehydrogenation catalysts.
It is well known in the art that if the alkanol used for esterification is high-boiling, the overhead product of the intermediate distiliation step delivered via stream [6] for hydrogenation or dehydrogenation may have a significant amount of the alkanol mixed with the corresponding ester. Accordingly, the 20 alkanol is recovered and recycled after the hydrogenation or dehydrogenation step.
The methodologies used to establish operating conditions to purify an ester or a mixed ester and alkanol stream via distillation are well known to those familiar with the art.
Hydrogenation: Reactor assemblies used for ester hydrogenation are well known to those familiar with the art. They are typically tubular reactors constructed with 316 Stainless Steel capable of withstanding high temperatures and pressures. The reactors are constructed with temperature and pressure regulation capabilities in order to affect the hydrogenation equilibrium such that the desired product distribution can be obtained.
Numerous catalysts and supports are employed for hydrogenation.5 The appropriate choice for the catalyst and support combination for succinate ester hydrogenation is well known to those familiar with the art. Typically the ester feed to the reactor via stream [6] is measured as weight hourly space velocity, which can range from about 0.5 to about 1.5 grams of ester per gram of catalysts per hour. The ester feed can be diluted with the corresponding alkanol and consequently the feed compositions could range from about 0 to about 50 % of alkanol. Hydrogen is fed via stream [7] using high pressure regulators and the hydrogen:ester feed ratio will vary between about 100:1 and about 300:1. Reactors are equipped with apparatus for collection of both condensable and non-condensable products (stream [8]) for post reaction analysis using analytical techniques familiar to those practicing the art.
Dehydrogenation: Reactor assemblies used for ester dehydrogenation are well known to those familiar with the art and generally similar to that used for hydrogenation. They are typically tubular reactors constructed with 316 Stainless Steel capable of withstanding high temperatures and pressures.
The reactors are constructed with temperature and pressure regulation capabilities in order to affect the dehydrogenation equilibrium such that the desired product can be obtained in high conversion and yield. It is generally known that oxidative dehydrogenation is favored over conventional dehydrogenation since the presence of oxygen positively impacts the thermodynamic equilibrium of dehydrogenation.6 Numerous catalysts and supports are employed for dehydrogenation.s Typically the ester feed to the reactor via stream [6] is measured as weight hourly space velocity, which can range from about 0.5 to about 1.5 grams of ester per gram of catalysts per hour. The ester feed can be diluted with the corresponding alkanol and consequently the feed compositions could range from about 0 to about 50 %
of alkanol. Oxygen is fed via stream [7] using high pressure regulators and the oxygen:ester molar feed ratio will vary between about 1:1 to about 100:1.
For commercial operation, air could substitute for pure oxygen making the process more economical. Reactors are equipped with apparatus for collection of both condensable and non-condensable products (stream [8]) for post reaction analysis using analytical techniques familiar to those practicing the art.
REFERENCES:
1- Datta, R., "Process for the Production of Succinic Acid by Anaerobic Fermentation", U.S. Patent 5,143,833, 1992.
2- Berglund, K. A.; Yedur, S. K.; Dunuwila, D. D., "Succinic Acid Production and Purification", U. S. Patent 5,958,744, 1999.
3- Yedur, S. , Berglund, K. A., Dunuwila, D. D., "Succinic Acid Production and Purification", U.S. Patent 6,265,190, July 24, 2001.
4- Berglund, K. A.; Elankovan, P.; Glassner, D. A., "Carboxylic Acid Purification and Crystallization Process", U. S. Patent 5,034,105, 1991.
5- Varadarajan, S, et. AI., "Catalytic Upgrading of Fermentation-Derived Organic Acids," Biofechnol. Prog., 1999, 15, 845-854.
6- Yedur, S. K., et al., "Synthesis and Testing of Catalysts for the Production of Maleic Anhydride from a Fermentation Feedstock," Ind. Eng. Chem. Res., 35, p 663-671, (1996).
1- Datta, R., "Process for the Production of Succinic Acid by Anaerobic Fermentation", U.S. Patent 5,143,833, 1992.
2- Berglund, K. A.; Yedur, S. K.; Dunuwila, D. D., "Succinic Acid Production and Purification", U. S. Patent 5,958,744, 1999.
3- Yedur, S. , Berglund, K. A., Dunuwila, D. D., "Succinic Acid Production and Purification", U.S. Patent 6,265,190, July 24, 2001.
4- Berglund, K. A.; Elankovan, P.; Glassner, D. A., "Carboxylic Acid Purification and Crystallization Process", U. S. Patent 5,034,105, 1991.
5- Varadarajan, S, et. AI., "Catalytic Upgrading of Fermentation-Derived Organic Acids," Biofechnol. Prog., 1999, 15, 845-854.
6- Yedur, S. K., et al., "Synthesis and Testing of Catalysts for the Production of Maleic Anhydride from a Fermentation Feedstock," Ind. Eng. Chem. Res., 35, p 663-671, (1996).
Claims (17)
1. A process for producing an ester of carboxylic acid from a fermented broth, the process comprising:
a) providing a fermented broth containing at least one carboxylic acid and salts thereof; and b) obtaining the ester of carboxylic acid by subjecting the carboxylic acid salt to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst.
a) providing a fermented broth containing at least one carboxylic acid and salts thereof; and b) obtaining the ester of carboxylic acid by subjecting the carboxylic acid salt to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst.
2. The process of claim 1, wherein the fermented broth results from the fermentation of a carbohydrate source by a carboxylic acid producing organism.
3. The process of claim 2, wherein the fermentation is conducted in the presence of COZ and a base to produce a salt of the carboxylic acid.
4. The process of claim 3, wherein the base is NH3, K, Na, Ca or Mg.
5. The process of claim 3, wherein the base is an amine.
6. The process of claim 2, wherein the fermentation is conducted in the presence of CO2 and NH3 to obtain an ammonium salt of the carboxylic acid.
7. The process of claim 6, wherein the CO2 and NH3 used for the anaerobic fermentation of the carbohydrate source are recovered from the esterification step.
8. The process of claim 2, wherein the carboxylic acid producing organism is Aspergillus niger, Corynebacterium glutamicum (also called Brevibacterium flafum), Escherichia coli, Enterococcus faecalis, Veillonella parvula, Actinobacillus succinogenes, Mannheimia succiniciproducens, Anaerobiospirillum succiniciproducens, Paecilomyces varioti, Saccharomyces cerevisiae, Bacteroides fragilis, Bacteroides ruminicola, Bacteroides amylophilus, any other organism capable of producing carboxylic acids, or a mixture thereof.
9. The process of any one of claims 1 to 8, wherein prior to esterification step b), the broth containing the at least one carboxylic acid salt is concentrated using vacuum evaporation.
10. The process of any one of claims 1 to 9, wherein the alkanol is methanol, ethanol, propanol, butanol, or amyl alcohol.
11. The process of any one of claims 1 to 10, wherein the carboxylic acid salts are diammonium succinate, disodium succinate, dipotassium succinate, calcium succinate or magnesium succinate.
12. The process of claim 10, wherein the ester of carboxylic acid can be either a dimethyl succinate, diethyl succinate, dipropyl succinate, dibutyl succinate, or diamyl succinate.
13. The process of claim 1, wherein the ester of carboxylic acid is further subjected to a catalytic hydrogenation reaction.
14. The process of claim 1, wherein the ester of carboxylic acid is further subjected to a catalytic oxidative dehydrogenation reaction.
15. A process for producing esters of succinic acid from a fermentable broth, the process comprising:
a) providing a fermentable broth containing a carbohydrate source;
b) subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NH3 to obtain a fermented broth containing diammonium succinate;
c) concentrating diammonium succinate contained in the fermented broth using vacuum evaporation; and d) subjecting diammonium succinate to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form a dialkyl succinate where the dialkyl succinate is dimethyl succinate, diethyl succinate, dipropyl succinate, dibutyl succinate, or diamyl succinate.
a) providing a fermentable broth containing a carbohydrate source;
b) subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NH3 to obtain a fermented broth containing diammonium succinate;
c) concentrating diammonium succinate contained in the fermented broth using vacuum evaporation; and d) subjecting diammonium succinate to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form a dialkyl succinate where the dialkyl succinate is dimethyl succinate, diethyl succinate, dipropyl succinate, dibutyl succinate, or diamyl succinate.
16. A process for producing 1,4-butanediol (BDO), tetrahydrofuran (THF), and gamma-butyrolactone (GBL) from a fermentable broth, the process comprising :
a) providing a fermentable broth containing a carbohydrate source;
b) subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NH3 to obtain a fermented broth containing diammonium succinate;
c) concentrating diammonium succinate contained in the fermented broth using vacuum evaporation;
d) subjecting diammonium succinate to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinates; and e) subjecting dialkyl succinates to a catalytic hydrogenation reaction to form BDO, THF and/or GBL;
where the dialkyl succinate is dimethyl succinate, diethyl succinate, dipropyl succinate, dibutyl succinate, or diamyl succinate.
a) providing a fermentable broth containing a carbohydrate source;
b) subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NH3 to obtain a fermented broth containing diammonium succinate;
c) concentrating diammonium succinate contained in the fermented broth using vacuum evaporation;
d) subjecting diammonium succinate to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinates; and e) subjecting dialkyl succinates to a catalytic hydrogenation reaction to form BDO, THF and/or GBL;
where the dialkyl succinate is dimethyl succinate, diethyl succinate, dipropyl succinate, dibutyl succinate, or diamyl succinate.
17. A process for producing dialkyl maleate from a fermentable broth, where the dialkyl maleate is dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, or diamyl maleate the process comprising :
a) providing a fermentable broth containing a carbohydrate source;
b) subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NH3 to obtain a fermented broth containing diammonium succinate;
c) concentrating diammonium succinate contained in the fermented broth using vacuum evaporation;
d) subjecting diammonium succinate to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinate; and e) subjecting dialkyl succinate to a catalytic oxidative dehydrogenation reaction to form dialkyl maleate where the dialkyl maleate is dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, and diamyl maleate.
a) providing a fermentable broth containing a carbohydrate source;
b) subjecting the fermentable broth to an anaerobic fermentation in the presence of CO2 and NH3 to obtain a fermented broth containing diammonium succinate;
c) concentrating diammonium succinate contained in the fermented broth using vacuum evaporation;
d) subjecting diammonium succinate to an esterification in the presence of an alkanol under pressurized reactive distillation in the presence of CO2 as a catalyst to form dialkyl succinate; and e) subjecting dialkyl succinate to a catalytic oxidative dehydrogenation reaction to form dialkyl maleate where the dialkyl maleate is dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, and diamyl maleate.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002657666A CA2657666A1 (en) | 2008-03-13 | 2009-03-10 | Process for the direct production of esters of carboxylic acids from fermentation broths |
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| Application Number | Priority Date | Filing Date | Title |
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| CA002625511A CA2625511A1 (en) | 2008-03-13 | 2008-03-13 | Process for the direct production of esters of carboxylic acids from fermentation broths |
| CA2,625,511 | 2008-03-13 | ||
| CA002657666A CA2657666A1 (en) | 2008-03-13 | 2009-03-10 | Process for the direct production of esters of carboxylic acids from fermentation broths |
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| CA2657666A1 true CA2657666A1 (en) | 2009-09-13 |
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| CA002625511A Abandoned CA2625511A1 (en) | 2008-03-13 | 2008-03-13 | Process for the direct production of esters of carboxylic acids from fermentation broths |
| CA002657666A Abandoned CA2657666A1 (en) | 2008-03-13 | 2009-03-10 | Process for the direct production of esters of carboxylic acids from fermentation broths |
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| CN107778145B (en) * | 2016-08-30 | 2020-11-13 | 中国石油化工股份有限公司 | Method for producing 1, 4-butanediol and/or sec-butanol |
| DE102016220662A1 (en) | 2016-10-21 | 2018-04-26 | Thyssenkrupp Ag | Process for the preparation of at least one hydrogenated compound from a carboxylic acid derivative |
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