Abstract: The present invention is directed to a method for the production of D,L-aspartic acid. The method comprises reacting an unsaturated dicarboxylic acid or anhydride, such as, maleic acid, fumaric acid, maleic anhydride, or mixtures thereof, with excess aqueous ammonia at an elevated temperature and pressure for a time sufficient to produce diammonium D,L-aspartate. The produced diammonium D,L-aspartate is then neutralized to D,L-aspartic acid. Excess unreacted ammonia and various by-products may be recycled and re-used in the method, thereby minimizing waste and reducing cost. The produced D,L-aspartic acid may be subsequently used to make polyaspartic acid.

Abstract: An improved method for isolating and purifying a glutathione derivative is disclosed. More particularly, the invention provides a method for isolating and purifying S-(1, 2-dicarboxyethyl)glutathione or its pharmacologically acceptable salt from a reaction mixture available upon reacting glutathione or its salt with either fumaric acid or its salt or maleic acid or its salt, which comprises a first step of converting the S-(1, 2-dicarboxyethyl)glutathione or salt thereof in the reaction mixture to the corresponding copper salt, dissolving the copper salt in an aqueous solution of acetic acid, formic acid or propionic acid, and removing the contaminant glutathione, oxidized glutathione and fumaric acid copper salts with the aid of activated carbon and a second step of dissolving or suspending the isolated S-(1,2-dicarboxyethyl)glutathione copper salt in water and blowing hydrogen sulfide gas through the resulting aqueous solution or suspension to remove copper.

Abstract: A process is disclosed for preparing D,L-aspartic acid by beating aqueous solutions of ammonium salts of the maleic acid. The molar ratio of maleic acid to ammonia ranges from 1:1 to 1:50. The process is carried out at temperatures from 60.degree. to 250.degree. C. and pressures of at least 1 bar. The pressure applied during the reaction is adjusted to ensure that the reaction mixture is almost completely present in liquid phase. Excess ammonia is removed and the reaction solution is acidified so as to release D,L-aspartic acid, which is then isolated.

Abstract: The invention relates to a process for removing amino acids and/or aminosulphonic acids from preferably aqueous solutions which contain these as impurities by adsorbing the amino acids on zeolites. Solutions to which the process according to the invention can be applied are produced, for example, from the industrial synthesis of oligopeptides in which the amino acids serving as starting materials are always present in solution, sometimes to a not inconsiderable residual concentration, together with the desired end product.

Abstract: A process is disclosed for isolating the disodium salt of racemic and meso isomers of ethylenediamine-N,N'-disuccinic acid from alkaline aqueous solutions.

Abstract: A process is provided for obtaining high-purity valine in high yield by a simple method using an inexpensive precipitant of p-isopropylbenzene sulfonic acid or a water-soluble salt thereof.

Abstract: A method of recovering a desired amino acid such as L-lysine from an aqueous solution containing the desired amino acid and impurities, includes the steps of passing the solution over a primary cation exchange resin to adsorb the desired amino acid onto the resin at a pH lower than the isoelectric point of the desired amino acid, eluting the desired amino acid from the resin using a suitable eluent having a pH higher than the isoelectric point of the desired amino acid to produce a first solution, passing the first solution over a secondary cation exchange resin to adsorb one or more of the impurities and to produce a second solution leaving the resin, collecting the second solution until the ratio of the concentrations of a selected impurity to the desired amino acid reaches a chosen value to produce a third solution which contains a lower level of impurities than the first solution, and recovering the desired amino acid from the third solution.

Abstract: This invention provides a process for the preparing of (S) (+)-4,4'-(1-methyl-1,2-ethanediyl)-bis-(2,6-piperazinedione) (ICRF-187), by synthesizing a crude mixture comprising a 1,2-diaminopropane tetraacetic acid intermediate and byproducts; and then subjecting the tetraacetic acid intermediate, as part of the crude mixture, to ring formation in the presence of the byproducts, thereby producing ICRF-187 in commercially useful amounts.

Abstract: A process for the isolation of L-leucine and L-isoleucine from an aqueous solution containing these amino acids and their separation from each other by contacting the solution with a zeolite under acid conditions.

Abstract: A method for producing an aqueous solution of an aminocarboxylic acid from an aqueous solution of an alkali metal salt of the aminocarboxylic acid is disclosed. The first step of the method is to adjust the pH of the aqueous solution of the alkali metal salt of the aminocarboxylic acid to between about 1.0 and about 3.0. This is done by adding a monovalent inorganic acid to the aqueous solution of the alkali metal salt of the aminocarboxylic acid to form an aqueous feed solution containing protonated aminocarboxylic acid and an inorganic alkali salt having an inorganic anion and an alkali metal cation. The second step of the method is to pass the aqueous feed solution through at least one membrane using a diafiltration process to separate the aqueous feed solution into an aqueous permeate solution, containing the alkali metal cation, and an aqueous retentate solution containing the aminocarboxylic acid.

Abstract: L-aspartic acid is improvedly prepared in high yields by treating ammonium aspartate, advantageously in aqueous reaction medium, with an effective, aspartic acid-precipitating amount of fumaric acid.

Abstract: This invention relates to a method for converting calcium salts of [S,S]-ethylenediamine-N,N'-disuccinic acid to an easily filterable precipitate of [S,S]-ethylenediamine-N,N'-disuccinic acid.

Abstract: A process for the crystallization of DL-methionine from a crystallization medium comprising DL-methionine and an aluminium salt of an organic acid.

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: Glycine and sodium sulfate decahydrate are separated from a starting aqueous solution containing glycine, sodium sulfate, and impurities, by forming a slurry which is a solid mixture of glycine and sodium sulfate decahydrate, followed by separation of the mixed crystals.

Abstract: A process for the separation of amino acids from aqueous solutions by adsorption on zeolites of different types. It is unnecessary to separate the biomass prior to the treatment.

Abstract: Process for preparing N-phosphono-methyl-iminodiacetic acid by means of phosphonomethylation of iminodiacetic acid performed by reacting an aqueous solution of phosphoric acid and hydrochloric acid, obtained by hydrolysis of phosphorous trichloride, with iminodiacetic acid and formaldehyde, in which phosphorous trichloride is hydrolysed in step (a) with water or an aqueous solution or hydrochloric acid, the reaction temperature and amount of water are regulated such that an aqueous solution of hydrochloric acid and phosphoric acid in a molar ratio of 0.5:1 to 2:1 is formed, and gaseous hydrochloric acid is caused to develop from the reaction medium. The phosphonomethylation reaction is performed in the solution obtained in step (a) in the presence of iminodiacetic acid in a molar ratio of iminodiacetic acid to phosphoric acid between 1:1 and 1:1.2 with the addition of formaldehyde. The N-phosphono-methyl-iminodiacetic acid is then recovered from the reaction medium.

Abstract: A method for the recovery of .alpha.-L-aspartyl-L-phenylalanine methyl ester, L-phenylalanine and L-aspartic acid from the mother liquor obtained by the solid-liquid separation of a suspension of .alpha.-L-aspartyl-L-phenylalanine methyl ester crystals is disclosed.

Abstract: A process for reducing the residual content of free alkylating agent in aqueous solutions of amphoteric or zwitterionic surface-active agents by aftertreatment with ammonia, an amino acid containing 2 to 8 carbon atoms, or an oligopeptide.

Abstract: The present invention relates to chiral supports and to their use in the asymmetric synthesis, deracemization and optical inversion of organic chiral compounds. In particular, the supports are used in combination with thermal equilibration of a species having a reactive achiral portion. Preferably, these supports are obtained by the copolymerization of at least one chiral unit and at least one functionalizing unit or by the polymerization of at least one chiral unit which is a source of said functionalizing unit. Optionally, a crosslinking agent is utilized. By utilizing these supports and thermal equilibration, excess enantiomers can be produced.

Abstract: The present invention relates to chiral polymers and to their uses for operations of asymmetric synthesis, deracemization and optical inversion.These polymers are characterized in that they comprise:a chiral unita functionalizing unitan optional crosslinking unitApplication to chiral organic synthesis.

Abstract: A method for purification of an amino acid which comprises contacting an amino acid solution containing impurities with an ion exchange resin to selectively adsorb the amino acid onto the resin, eluting and recovering the adsorbed amino acid whereby the resin is contacted with the amino acid solution in countercurrent continuous multiple steps during adsorption and an eluent is contacted with the adsorbed resin in countercurrent continuous multiple steps during elution.

Abstract: A method for purifying glycine characterized by comprising the steps of adjusting the pH of an aqueous glycine solution to 6 or less with a mineral acid and/or an organic acid or an acidic cation exchange resin and subsequently decoloring said aqueous glycine solution by active carbon treatment.

Abstract: A process for the preparation of optically pure .alpha.-amino acids comprising the nucleophilic ring-opening of 3-amino-2-oxetanone salts. N-Protected serine .beta.-lactones are deprotected to form heretofore unknown 3-amino-2-oxetanone and its corresponding salts. In turn these previously unknown 3-amino-2-oxetanone salts may be used in the synthesis of other novel or rare stereochemically-pure free amino acids.

Abstract: The pure isomers L-buthionine-S-sulfoximine and L-buthionine-R-sulfoximine are provided. The L-S-isomer has utility, for example, in causing the depletion of glutathione, a major protectant molecule in tumors and certain parasites. The L-R-isomer has utility as a compound decreasing further uptake and thus effect of the L-S-isomer and for causing glutathione depletion specific to the kidney. The isolation of pure isomers from L-buthionine-SR-sulfoximine enables treatment at lower dosages without cross effects.The pure L-buthionine-S-sulfoximine isomer is obtained from L-buthionine-SR-sulfoximine by recrystallization preferably by forming a solution of L-buthionine-SR-sulfoximine in water at a concentration of 0.

Abstract: N-methyliminodiacetic acid is separated from mixtures of N-methyliminodiacetic acid and sodium sulfate formed by acidification of solutions of its disodium salt with sulfuric acid. Thus the disodium salt is acidified with sulfuric acid to a ph of about 2 and concentrated by evaporating water so as to crystallize sodium sulfate. The sodium sulfate is separated, and the resulting mother liquor is cooled to precipitate N-methyliminodiacetic acid, which is then separated.

Abstract: A large number of customary processes for separating amino acids fails when very polar hydrophilic amino acids with isoelectric points (IEP) which are close to one another are to be fractionated. Mixtures of L-glutamic acid (IEP=3.24) and L-phosphinothricin (IEP=2.6) produced by enzymatic transaminations of the corresponding .alpha.-keto acid have been difficult to separate to date. The invention relates to a process for separating L-phosphinothricin and L-glutamic acid, which comprises carrying out the separation as liquid/liquid extraction with two non-miscible aqueous phases as phase system, where the phase former contained in the phase system is a combination of at least two different water-soluble polymers or of at least one water-soluble salt and one water-soluble polymer, and the extraction is carried out by multistage countercurrent partition on the van Dijck principle.

Abstract: A method for crystallization of an amino acid characterized by allowing a surfactant and/or an alcohol to exist upon crystallization.

Abstract: Carboxylic acids are recovered from wet organic solutions by reducing the solutions' water content thus causing the acids to precipitate as recoverable crystals.

Abstract: A method of preparing solid hydroxyalkylamides by reacting carboxylic alkyl esters with alkanolamines at controlled reaction temperatures, removing the alcohol byproduct, controlling the temperature of the reaction mixture to form a slurry, maintaining the slurry and recovering the solid hydroxyalkylamides.

Abstract: The invention relates to pharmaceutical compositions as well as the preparation thereof which are useful for improving the status of patients suffering from external otitis or otitis (otitis media), or particularly from a chronic otitis (otitis media chronica). The pharmaceutical compositions according to the invention contain a sulfhydryl-containing compound, an antibacterial chemotherapeutic agent, an aspecific antiinflammatory agent and optionally a kerotolytic agent. The compositions preferably contain N-acetyl-L-cysteine as sulfhydryl-containing compound.

Abstract: A process for removing metal salts from an H.sub.4 EDTA precipitate by esterification with an esterification reagent to produce an esterification mixture comprising a solid metal salt an EDTA ester and thereafter separating the solid metal salt from the esterification mixture.

Abstract: Disclosed is a process for preparing DL-serine, which comprises synthesizing DL-serine according to Strecker reaction with use of a cyan compound, ammonium chloride, ammonia and a reaction substrate comprising glycol aldehyde, wherein the Strecker reaction is carried out under the reaction conditions of:molar ratios of the starting materials of:glycol aldehyde/cyan compound: more than 1.0 and not more than 1.50ammonium chloride/glycol aldehyde: more than 1.0 and not more than 2.0ammonium/cyan compound: 1.0 to 7.0reaction temperature: 20.degree. to 80.degree. C.reaction time: 15 to 120 minutes,and the reaction product obained in hydrolyzed.

Abstract: The separation and recovery of iminodiacetic acid and sodium sulfate decahydrate from sodium sulfate solutions such as the liquor generated in the production of iminodiacetic acids are disclosed. The separation is accomplished by adjusting the temperature of the sodium sulfate solutions to crystallize the iminodiacetic acid and sodium sulfate decahydrate. Nitrilotriacetic acid optionally can be isolated prior to the crystallization of the IDA and sodium sulfate decahydrate.

Abstract: Glycine and sodium sulfate decahydrate are separated from a starting aqueous solution containing glycine, sodium sulfate, and impurities, by forming a slurry which is a solid mixture of glycine and sodium sulfate decahydrate, followed by separation of the mixed crystals.

Abstract: L-glutamine is purified by concentrating a fermentation liquor containing at least 40 g/l or more of L-glutamine, or a solution obtained therefrom by filtering off microbial cells, at pH 5.6.+-.0.5, or by cooling the fermentation liquor or the solution after concentration or without concentration at a temperature in the range of 2.degree. to 30.degree. C., thereby giving a slurry of L-glutamine crystals of 70 g/l or higher concentration; (2) separating the crystals from the mother liquor and then dissolving the separated crystals in a water; and (3) bringing the solution thus obtained into contact with an OH-type anion-exchange resin, thereby removing impurities through adsorption.

Abstract: A process for isolating and purifying an amino acid, which comprises subjecting an aqueous solution of said amino acid containing impurities composed mainly of at least one member selected from the group consisting of acidic amino acids, lysine, ornithine, citrulline, histidine, PCA, sulfate ions, chloride ions and pigments to ion-exclusion chromatography using a strongly acidic cation exchange resin.

Abstract: The invention refers to a process for the preparation of L(-)carnitine by using dibenzoyl-D(31 )tartaric acid and crystallizating the relative salt at low temperature.

Abstract: The invention relates to the preparation of N-phosphono-methyl-imino-diacetic acid from the calcium salt of imino-diacetic acid in a simplified synthesis. The process comprises in that the imino-diacetic acid calcium salt is heated with concentrated hydrochloric acid in a molar ratio of 2-3:1 at a temperature between 50.degree.-100.degree. C., the obtained imino-diacetic acid hydrogen-chloride is separated then dissolved in water and is reacted with phosphorous acid in a molar ratio of 1.0-1.2:1 calculated for imino-diacetic acid hydrogen chloride and with the aqueous solution of formaldehyde in a molar ratio of 1.0-1.4:1 under stirring, and the obtained product is isolated.

Abstract: A method for purifying aspartic acid comprising suspending aspartic acid crystals containing chloride ion impurities in an aqueous solution at a temperature of 50.degree. C. or higher, followed by separating the purified aspartic acid crystals, is disclosed.

Abstract: Amino acids can be purpified and/or concentrated by extracting aqueous mixtures such as fermentation broths by contacting an aqueous mixture containing amino acids with an organic solution containing a water insoluble extractant selected from the group consisting of:1. A quaternary ammonium ion having the formula: ##STR1## where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are aliphatic, each having from 1 to 22 carbon atoms, and together have a minimum of 25 carbon atoms, and where at least three of the four R groups are at least a C.sub.4.2. A quaternary phosphonium ion having the formula: ##STR2## where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as defined above. 3. A tertiary sulfonium ion having the formula: ##STR3## where R.sub.1, R.sub.2 and R.sub.3 each are aliphatic with from 1 to 22 carbon atoms, and together have a minimum of 24 carbons and where at least two of these groups are at least a C.sub.6.4. An organic boride ion having the formula: ##STR4## where R.sub.1, R.sub.2, R.sub.3 and R.sub.

Abstract: Disclosed is a process for recovery of amino acids from aqueous mixtures. In particular, it relates to a treatment of said amino acid containing aqueous mixture prior to extraction of the amino acid with a water immiscible organic solution containing a water insoluble extractant for said amino acid. The overall process of the invention which includes the pretreatment and extraction, also includes optional methods of recovering said extracted amino acid from the water immiscible organic solution. Accordingly, the invention also relates to a process for recovery of the amino acid by stripping of the amino acid from the organic solution and precipitation of the amino acid.

Abstract: Process for extracting organic compounds which are present in water in the form of solutions or suspensions by a liquid carboxylic acid which is immiscible with water. Branched or unbranched linear acids such as n-heptanoic, n-octanoic, or 2-ethylhexanoic acids make it possible to quantitatively extract compounds such as phenols, amines or amino acids from such aqueous solutions, thereby rendering the process useful for the purification of industrial wastewaters.

Abstract: An aqueous solution containing amino acids of which the solubility in water at isoelectric point is low, can be highly concentrated by means of semipermeable membranes in the presence of a water-soluble organic solvent while increasing the solubility by adjusting a pH.

Abstract: L-lysine is recovered using an ion exchange resin. A liquid solution containing L-lysine and possibly impurities is contacted with the resin and is then soaked in elutant for at least about 15 minutes. The elution of L-Lysine from the resin is then continued.

Abstract: A method for the production of substantially 100% pure N.alpha.-urethane protected amino acids is disclosed. This method eliminates the formation of di-peptide and tri-peptide contaminants. Reaction of blocking reagents at the carboxylate site on a protected peptide is prevented by the application of labile amino acid esters. Subsequent removal of the ester yields, in ultra-high purity, the N.alpha.-protected amino acid. The substantially 100% pure N.alpha.-urethane protected amino acid are also disclosed.

Abstract: A method for separating leucine from a mixture of amino acids containing at least leucine and isoleucine, which comprises subjecting an aqueous solution of a mixture of amino acids to centrifugal force, and forcing by the application of pressure a water-saturated organic solvent immiscible with water to pass through the aqueous solution against the centrifugal force, to selectively extract leucine in said water-saturated organic solvent.

Abstract: A concentrated aqueous solution of the sodium salt of methionine, which is practically free from inorganic salts, is produced from the medium resulting from the hydrolysis of 5-(.beta.-mercaptoethyl)hydantoin.

Abstract: A method for racemizing an optically active amino acid, which comprises heating the optically active amino acid in an aqueous solution under an alkaline condition in the presence of an alkali metal salt.

Abstract: Process of purification of carnitine, in which the aqueous medium containing the carnitine is first acidified, in order to cause the proteins present to precipitate, and, after their separation, the water of the medium is replaced by a lower alcohol which dissolves carnitine, at least hot, while the mineral substances separate out.