Abstract: A process for the production of lactic acid and for the separation and/or recovery of lactic acid from a lactate feed solution. A lactate feed solution preferably obtained from a fermentation broth is combined with and extracted by a water immiscible trialkyl amine in the presence of carbon dioxide. Lactic acid is recovered from the resulting organic phase. Recovered carbonate or bicarbonate from the aqueous phase is preferably recycled to the fermentor and regenerated extractant is preferably recycled for use in the extraction.

Abstract: A process for preparing .alpha.-hydroxy acids by heating ammonium salts of .alpha.-hydroxy acids of general formula (I), removing the formed ammonia and water, adding water to the residue, and heating the obtained mixture, wherein R is hydrogen, C.sub.1 -C.sub.6 alkyl, alkyl(C.sub.1 -C.sub.6)thioalkyl (C.sub.1 -C.sub.6), phenyl or the like. This process is freed from the problem of disposal of by-products such as ammonium bisulfate and makes it possible to prepare a free .alpha.-hydroxy acid from an ammonium salt thereof economically and in a high yield.

Abstract: A method of recovering adipic acid and 6-hydroxycaproic acid from the waste solution of alkali metal salts of organic acids coming from the process of cyclohexane oxidation, which comprises:(i) basifying the reaction mixture coming from cyclohexane oxidation with an aqueous solution of an alkali-metal base so that the organic acids essentially comprising adipic acid and 6-hydroxycaproic acid therein, are saponified, extracting the formed alkali metal salts of organic acids from the mixture with water, then acidifying the aqueous extract comprising the alkali metal salts of organic acids to a pH value of 3 or lower with an aqueous solution of a protic inorganic acid, as a result, said aqueous extract is separated into an oily layer and an aqueous layer;(ii) extracting the organic acid from said oily layer obtained from the step (i) with an aqueous solution of a protic inorganic acid, to obtain an aqueous extract;(iii) extracting the organic acid from the aqueous layer obtained from the step (i) with an organic

Abstract: This invention provides a method for thermally converting volatile fatty acid (VFA) salts to ketones by mixing dry calcium salts of VFAs with hot heat transfer agent in an evacuated container, thereby causing thermal decomposition of the calcium salts of VFAs to form ketone-containing vapor and calcium carbonate; and separating the ketone-containing vapor from the calcium carbonate and heat transfer agent by condensing a mixture of ketones from the ketone-containing vapor. This invention also provides a process for conversion of VFA salts, produced by anaerobic fermentation of cellulosic biomass, into liquid fuels, volatile fatty acids, aldehydes, alcohols, and lactic acid.

Abstract: A continuous process for the preparation of 2-hydroxy-4-methylthiobutanoic acid which includes introducing sulfuric acid into a first reactor including a continuous stirred tank reactor and introducing 2-hydroxy-4-methylthiobutanenitrile into the first reactor. 2-hydroxy-4-methylthiobutanenitrile is continually hydrolyzed within the first reactor to produce an intermediate aqueous hydrolysis solution containing 2-hydroxy-4-methylthiobutanamide. The intermediate aqueous hydrolysis solution is continuously introduced into a plug flow reactor. 2-hydroxy-4-methylthiobutanamide is continually hydrolyzed within the plug flow reactor to produce an aqueous hydrolyzate product solution containing 2-hydroxy-4-methylthiobutanoic acid. 2-hydroxy-4-methylthiobutanoic acid is recovered from the aqueous hydrolyzate product solution.

Abstract: A process for treating a liquid comprising subjecting a liquid containing, in solution, citric acid as well as a less desirable component having a similar molecular weight to citric acid, to nanofiltration in a filtration step. From the filtration step, a permeate in which the ratio of the concentration of the citric acid to that of the less desirable component is greater than the ratio of the concentration of the citric acid to that of the less desirable component in the solution, is obtained.

Abstract: The process for purifying an .alpha.-, .beta.- or .gamma.-substituted carboxylic acid or a salt or an ester thereof or a mixture of two or more thereof from an aqueous solution which contains an .alpha.-, .beta.- or .gamma.-substituted carboxylic acid or a salt or an ester thereof or a mixture of two or more thereof and at least one polyol or at least one amino alcohol, wherein the solution is treated by electrodialysis.

Abstract: Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with an organic solution of alkylamine thus forming an alkylamine/carboxylic acid complex which is decomposed with improved efficiency to the desired carboxylic acid and the alkylamine. Carbon dioxide addition can be used to improve the adsorption or the carboxylic acids by the solid phase sorbent.

Abstract: The invention provides a process for the recovery of lactic acid from an aqueous liquor containing water and calcium lactate, comprising the extraction step of combining the lactate aqueous liquor with an extractant containing at least one water immiscible amine having a total of at least 18 carbon atoms in the presence of carbon dioxide to form an aqueous phase and an organic phase containing extracted lactic acid and the extractant and separating lactic acid from the organic phase, characterized in that a carbohydrate is added to the aqueous liquor, the carbohydrate being present in the aqueous liquor at a weight concentration of at least 10% of the water content thereof.

Abstract: A process for the production of lactic acid and for the separation and/or recovery of lactic acid from a lactate feed solution. A lactate feed solution preferably obtained from a fermentation broth is combined with and extracted by a water immiscible trialkyl amine in the presence of carbon dioxide. Lactic acid is recovered from the resulting organic phase. Recovered carbonate or bicarbonate from the aqueous phase is preferably recycled to the fermentor and regenerated extractant is preferably recycled for use in the extraction.

Abstract: The invention provides a process for the recovery of erythorbic acid from an aqueous feed solution containing values of erythorbic acid at a concentration of less than 0.7 mol/kg, comprising adsorbing a major portion of said erythorbic acid with a solid phase adsorbent resin selected from resins carrying a pyridine function and resins of similar or weaker basicity; separating said erythorbic acid-containing resin from residual aqueous solution, and subjecting said erythorbic acid-containing resin to a desorbing operation with a neutral solvent at a temperature of at least 20.degree. C. higher than the temperature at which said adsorption is carried out, whereby there is obtained a solution of erythorbic acid in solvent in which the concentration of erythorbic acid is at least equal to its concentration in said aqueous feed solution.

Abstract: Hydroxypivalic acid is obtained from aqueous solutions by removal of the water by azeotropic distillation and subsequent crystallization from a solvent mixture which is composed of a polar and a non-polar component. The distillation is carried out under reduced pressure and at a maximum bottom temperature of 90.degree. C., until a residual water content of at least 0.1% of the total weight of the resulting solution is achieved.

Abstract: A continuous process for the preparation of 2-hydroxy-4-methylthiobutanoic acid or a salt thereof which includes introducing an aqueous mineral acid into a nitrile hydrolysis reactor including a continuous stirred tank reactor and introducing 2-hydroxy-4-methylthiobutanenitrile into the nitrile hydrolysis reactor. 2-hydroxy-4-methylthiobutanenitrile is continually hydrolyzed within the nitrile hydrolysis reactor to produce a nitrile hydrolysis reactor product stream containing 2-hydroxy-4-methylthiobutanamide. The nitrile hydrolysis reactor product stream is continuously introduced into an amide hydrolysis flow reactor. 2-hydroxy-4-methylthiobutanamide is continually hydrolyzed within the amide hydrolysis flow reactor to produce an aqueous hydrolyzate product containing 2-hydroxy-4-methylthiobutanoic acid. 2-hydroxy-4-methylthiobutanoic acid is recovered from the aqueous hydrolyzate product.

Abstract: A process for the conversion of the sodium salt of 2-keto-L-gulonic acid, which is present in an aqueous fermentation solution, into an alcoholic solution of the free acid and, if desired, into an alkyl ester of the acid comprises a) recovering the sodium 2-keto-L-gulonate monohydrate from an aqueous fermentation solution by crystallization involving evaporation, cooling or displacement and, if desired, pulverizing the thus-obtained crystallizate by grinding, b1) suspending the optionally ground sodium 2-keto-L-gulonate monohydrate obtained in step a) in a lower alcohol, leaving the crystals to swell and thereafter adding an acid of low water content, whereby the measured pH value should lie above 1.5, or b2) adding the optionally ground sodium 2-keto-L-gulonate monohydrate obtained in step a) together with an about stoichiometric amount of an acid of low water content to a lower alcohol using a wet grinding system, whereby the measured pH value should lie above 1.

Abstract: The invention provides a process for the recovery of a water-soluble carblic or mineral acid having a pKa higher than 2 from an aqueous feed solution containing the acid or a salt thereof, comprising extracting the acid with a water-immiscible extractant composition, the composition comprising: (a) at least one secondary or tertiary aklyl amine, in which the aggregate number of carbon atoms is at least 20, as a primary extractant; and (b) a sterically hindered, polar, organic compound having at least 5 carbon atoms, a basicity weaker than that of the primary extractant, and temperature-sensitive, extraction-modifying properties; separating the acid containing the extractant and subjecting it to a stripping operation at a temperature of at least 20.degree. C.

Abstract: A process is described for producing acetals comprising reacting an aldehyde or a ketone with an alcohol in the presence of a titanium compound having an acetylacetone as a ligand, or in the presence of a compound selected from the group consisting of stannous chloride dihydrate, cerium chloride hexahydrate and bismuth chloride. The process can be used in the synthesis of unstable acetals or when water exists in the reaction mixture, and therefore the process can be used for a wide variety of applications.

Abstract: Recovery of carboxylic acid from an amine-based, water-immiscible organic extractant solution thereof that contains an enhancer, by extraction of the acid into an aqueous phase. A low molecular, at least partly water-miscible organic compound being a C.sub.2 -C.sub.5 alkanol, an acetate of a C.sub.1 -C.sub.3 alkanol and acetone is used as enhancer. In operation, the enhancer is recovered and recycled. The process is applicable, among others, to the recovery of carboxylic acid from a fermentation broth.

Abstract: A process for the production of lactic acid and for the separation and/or recovery of lactic acid from a lactate feed solution. A lactate feed solution preferably obtained from a fermentation broth is combined with and extracted by a water immiscible trialkyl amine in the presence of carbon dioxide. Lactic acid is recovered from the resulting organic phase. Recovered carbonate or bicarbonate from the aqueous phase is preferably recycled to the fermentor and regenerated extractant is preferably recycled for use in the extraction.

Abstract: Recovery of carboxylic acid from an amine-based, water-immiscible organic extractant solution thereof that contains an extraction enhancer, by extraction of acid into an aqueous phase. In a preliminary step the enhancer is removed from the extractant solution by extraction with an aqueous solution containing at least 50 % by weight of a salt of the carboxylic acid present in the extractrant. The process is applicable to the recovery of carboxylic acid from a fermentation broth.

Abstract: A process is described for producing organic acids such as lactic acid. The process includes the steps of producing lactic acid by fermentation, resulting in an aqueous fermentation broth containing lactic acid, and adding a calcium base, such as calcium carbonate, to the fermentation broth, thereby producing calcium lactate in the broth. Biomass is removed from the broth, thereby leaving an aqueous solution or dispersion of calcium lactate. The calcium lactate is reacted with a source of ammonium ions, such as ammonium carbonate, or a mixture of ammonia and carbon dioxide, thereby producing an ammonium lactate. Contaminating cations can be removed by ion exchange. The free lactic acid or a derivative thereof can be separated from the ammonium ions, preferably by salt-splitting electrodialysis.

Abstract: Process for the manufacture of xylaric acid, characterized in that it consists of the oxidative degradation of 5-ketogluconic acid in alkaline medium using oxygen or a gas containing it.The xylaric acid obtained is of use as a calcium-chelating agent or as a component of polyhydroxypolyamides or as an intermediate in the synthesis of xylitol.

Abstract: The present invention relates to methods and apparatus for reducing the fouling of ion-selective membranes used in the electrodialytic purification of organic acids. More particularly, the present invention relates to the use of nanofiltration and chelating agents for removal of impurities from an organic acid-containing feed material to reduce the fouling of ion-selective membranes used in electrodialysis.

Abstract: The subject of the invention is a process for extracting pure lactic acid from fermentation liquors by ion exchange chromatography on a strongly acidic cation exchanger, preferably in H.sup.+ form. In a first step, the NH.sub.4 lactate coming from the fermentation is converted into the free acid by genuine ion exchange. This conversion is preferably effected on a weakly acidic cation exchanger in H.sup.+ form.

Abstract: Rapid temperature rises which characterize carbohydrate-nitric acid oxidation reactions used to form carbohydrate-derived acids may be moderated and temperature control readily maintained by blowing a gas such as air, oxygen, nitrogen or the like into the reaction mixture as needed to control the temperature of the reaction. The more moderate reaction conditions afford higher yield of the desired product with a concomitant reduction of byproducts which may be difficult to remove and usually are unwanted as well. Upon completion the oxidation mixture is made basic (e.g. with an alkali metal base hydroxide or carbonate, ammonia or an amine) to a pH at which the the carboxyl group or groups of the product carbohydrate-derived acid are entirely in the salt form. The aqueous solution is then passed through an ion retardation resin column to recover the carbohydrate-derived salt, using water as the eluent.

Abstract: This invention embodies a process for releasing acidic organic compounds in high yield and good purity from aqueous solutions of their salts which comprises converting the salts by carbon dioxide to their corresponding free acidic organic compounds and metal hydrogen carbonates, removing the acidic organic compounds from the mixture by extraction with an essentially water-insoluble organic solvent, and re-extracting the organic phase with carbon dioxide containing water. Using this process, the acidic organic compounds are completely released from their corresponding salts, i.e., the organic solution is free of salt. The acidic organic compounds released by the claimed process are organic compounds which contain acidic protons which can be replaced by metals. Some examples are carboxylic acids, sulfonic acids, phosphonic acids, phenols, naphthols, and aliphatic alcohols.

Abstract: A process for the production of lactic acid and for the separation and/or recovery of lactic acid from a lactate feed solution. A lactate feed solution preferably obtained from a fermentation broth is combined with and extracted by a water immiscible trialkyl amine in the presence of carbon dioxide. Lactic acid is recovered from the resulting organic phase. Recovered carbonate or bicarbonate from the aqueous phase is preferably recycled to the fermentor and regenerated extractant is preferably recycled for use in the extraction.

Abstract: Lactic acid formed via fermentation generally is susceptible to the development of color bodies when heated to temperatures of approximately 180.degree. C. and above. Color development appears to result from carbonization of small amounts of carbohydrates. Consequently a heat-stable lactic acid may be produced by subjecting an aqueous solution of lactic acid to temperatures between about 180 and 230.degree. C. for a time sufficient to carbonize the carbohydrates, with subsequent removal of the color bodies using standard decolorants such as activated charcoal. Heat treatment may be applied either directly to the broth or to an aqueous solution resulting from one or more processing steps applied to the fermentation broth.

Abstract: A process for the purification and recovery of 2,2'-oxydisuccinate moieities from a reaction mixture containing maleate, malate, fumarate, and alkaline earth metal is disclosed which reduces the pH to about 3.8 to 4.2 with sulfuric acid and then produces the calcium salt of the 2,2'-oxydisuccinate by heating and precipitation.

Abstract: A process for the preparation of enriched reaction mixtures containing 2,2'-oxydisuccinate (alkaline earth metal salts) is disclosed, by pH reduction and removal of alkaline earth metal malates.

Abstract: This invention provides an improved method for recovering an organic acid as a salt from various process streams by addition of a crystallizing base to a concentrated solution of neutralized organic acid. The addition of such a base causes crystallization of the salt. This process provides more efficient recovery of organic acid salt from a fermentation process stream than traditional crystallization and it may be used essentially as a one step purification process. The improved method is particularly applicable to the recovery of trisodium or tripotassium citrate from process streams produced in the fermentation and recovery of citric acid, with the addition of a crystallizing base such as sodium hydroxide, sodium carbonate, potassium hydroxide, or ammonia. The resulting product may be combined with an anticaking agent and/or dried to provide a particularly free flowing product.

Abstract: At least 99% pure 2,2'[oxybis (methylene)]bis-2-propenoic acidCH.sub.2 .dbd.C(COOH)CH.sub.2 --O--CH.sub.2 C(COOH).dbd.CH.sub.2is prepared by hydrolyzing an ester thereof in an aqueous basic medium and then acidifying the resultant salt.

Abstract: An organic acid can be recovered from a fermentation broth by clarifying the broth to remove at least a substantial portion of the impurities therein, producing a clarified feed; acidulating the clarified feed by adding a quantity of a mineral acid effective to lower the pH of the feed to between about 1.0 and about 4.5, producing an acidulated feed which is substantially saturated with respect to at least one electrolyte selected from the group consisting of MHSO.sub.4, M.sub.2 SO.sub.4, M.sub.3 PO.sub.4, M.sub.2 HPO.sub.4, MH.sub.2 PO.sub.4, and MNO.sub.3, where M is selected from the group consisting of Na, NH.sub.4, and K; extracting the acidulated feed with an extraction mixture which includes (a) water, (b) a mineral acid, in a quantity effective to maintain the pH of the feed between about 1.0 and about 4.

Abstract: In the production of citric acid aqueous mother liquor originating from a lime/sulfuric acid process is subjected to a multi-stage counter-current extraction with an amine based organic extractant. A solution of a further amount of citric acid derived from direct extraction of a citric acid fermentation broth is judicously injected into the organic phase stream in the counter-current extraction and a combined extract is withdrawn from the operation. This extract can be subjected to any known treatment for the recovery of citric acid values.

Abstract: Carboxylic acids are sorbed from aqueous feedstocks into an organic liquid phase or onto a solid adsorbent. The acids are freed from the sorbent phase by treating it with aqueous alkylamine thus forming an alkylammonium carboxylate which is dewatered and decomposed to the desired carboxylic acid and the alkylamine.

Abstract: A process for the preparation of an alkali metal citrate which comprises:(a) adjusting the pH of an aqueous solution containing citric acid to a value greater than 5.4;(b) contacting the aqueous solution with a polymeric adsorbent;(c) eluting the resulting charged polymeric adsorbent with an eluant comprising an aqueous solution of a soluble alkali metal hydroxide or alkali metal salt in which the alkali metal corresponds to the alkali metal of the alkali metal citrate to be produced; and(d) recovering an aqueous solution of the alkali metal citrate, is disclosed.

Abstract: This invention provides an improved method for recovering an organic acid as a salt from various process streams by addition of a crystallizing base to a concentrated solution of neutralized organic acid. The addition of such a base causes crystallization of the salt. This process provides more efficient recovery of organic acid salt from a fermentation process stream than traditional recrystallization and it may be used essentially as a one step purification process. The improved method is particularly applicable to the recovery of trisodium or tripotassium citrate from process streams produced in the fermentation and recovery of citric acid, with the addition of a crystallizing base such as sodium hydroxide, potassium hydroxide or ammonia.

Abstract: The present invention relates to a process for inexpensively and effectively recovering a high-purity organic acid, according to which a crude organic acid is subjected to extraction treatment with an organic solvent to obtain an organic solvent extract containing an organic acid; the organic solvent extract is mixed with a high-pressure gas to precipitate and separate impurities thereby obtaining a solution containing a high-purity organic acid; and the organic acid is separated from the solution to obtain a high-purity organic acid.

Abstract: The depolymerization of poly(hydroxyacids) in a liquid medium is enhanced by the presence of a quaternary ammonium compound. Poly(hydroxyacid) polymers containing a quaternary ammonium salt are more readily depolymerized.

Abstract: Rapid recovery from waste of high molecular weight polyhydroxyacid content by depolymerizing the PHA in acidic water.

Abstract: Polyhydroxyacid (PHA) is recovered by heating under pressure in the presence of a C.sub.1 -C.sub.6 alcohol, and optionally also water.

Abstract: Depolymerizing polyhydroxy acid by heating with the alcohol of 1-6 carbon atoms in the presence of an acid catalyst to produce an alkyl ester.

Abstract: A process for separating an organic acid or acids from an organic acid-containing solution obtained by a fermentation method in which glucose is used as starting material, which comprises contacting said organic acid-containing solution to a cation exchange resin to have the organic acid or acids adsorbed on the cation exchange resin, then contacting the cation exchange resin to an eluent to have the organic acid or acids desorbed, and then separating from the eluate a solution containing the organic acid or acids, wherein said organic acid-containing solution is contacted to the cation exchange resin under such a condition that the pH or the organic acid-containing solution is maintained at a pH level lower than pKa where Ka is the ionization constant of the organic acid or acids or the primary ionization constant in a case of a polybasic acid or acids, and the pH of the eluate is maintained at the above pH level.

Abstract: The known liming sulfuric acid process for the recovery of crystalline citric acid from a fermentation broth is modified by subjecting the mother liquor from the crystallization to extraction with a water-immiscible organic extraction that contains an amine. The resulting extract is neutralized with a recycled brine with alkali citrate and alkali citrate is crystallized from the concentrated brine obtained this way.

Abstract: Recovery of polyhydroxy acids (PHAs) from waste containing high molecular weight polyhydroxy acid polymer by depolymerizing the PHA in water at elevated temperature and pressure.

Abstract: Purified lactic acid aqueous solutions obtained by percolating fermentation broths through columns of appropriate ion-exchange resins.

Abstract: The production of high purity lactate ester or lactic acid from a concentrated fermentation broth by continuous acidification in the presence of an alcohol diluent with sequential or simultaneous esterification, distillation off of high purity ester, and, if desired, hydrolysis of the ester to high purity lactic acid.

Abstract: The invention relates to a process for the recovery of perfluoroethercarboxylic acids from the crude product of the electrochemical conversion of these acids or of one of their soluble salts to perfluorinated ethers, in which the perfluoroethercarboxylic acids and their esters contained in the crude product are separated off with the aid of a solid basic alkali metal salt or its solution and converted, by reaction of the resulting salts with a strong acid, to the corresponding perfluoroethercarboxylic acids.

Abstract: Processes are described for recovering lactic acid from impure lactide and the residue produced in the depolymerization of polylactic acid to lactide. Lactic acid is recovered from the impure lactide by a dual solvent extraction process and, from the polylactic acid residue by hydrolysis. The lactic acid recovered from the impure lactide and the depolymerization residue is recycled to provide for a high yield lactide process.

Abstract: Process for extracting lactic acid from aqueous acidic media is disclosed which process includes treatment with a complexing macrocyclic octol and organic solvent immiscible with water, separating the organic phase containing the lactic acid-macrocyclic octol complex thereby formed, which releases the lactic acid by treatment with alkaline water or with methanol.

Abstract: An organic acid is separated from a fermentation broth by using an adsorbent comprising a water-insoluble macroreticular or gel weakly basic anionic exchange resin possessing tertiary amine or pyridine functional groups or a strongly basic anionic exchange resin possessing quaternary amine functional groups. The resins are in sulfate form and have a cross-linked acrylic or styrene resin matrix. The organic acid is desorbed with water or dilute inorganic acid, e.g., sulfuric. The pH of the feed is maintained below the first ionization constant (pKa.sub.1) of the organic acid to obtain high selectivity.