摘要:
The invention relates to a process for the preparation of methionine of high bulk density, in which a mixture which comprises a compound which has a foaming action and a compound which influences the crystallization is added to the hydrolysis solution, and to the mixture itself.
摘要:
This disclosure relates to a process for preparing D,L-methionine by feeding carbon dioxide to an aqueous potassium methioninate solution obtained by hydrolysis of 5-(2-methylmercaptoethyl)hydantoin, in order to precipitate out crude methionine, which is separated off and purified. In this process an aqueous solution of the separated-off crude methionine is purified by recrystallization from a solution containing potassium ions and also a crystallization additive. The crystallization additive is a nonionic or anionic surfactant, or a mixture of different nonionic or anionic surfactants. The recrystallization occurs by introducing a 60 to 110° C.-hot methionine solution into a 35 to 80° C.-warm methionine suspension, a temperature of which is lower than that of the introduced solution, such that the temperature of the methionine suspension being maintained between 35 and 80° C. during the addition. The crystallization additive is a sorbitan fatty acid ester or a mixture of different sorbitan fatty acid esters.
摘要:
A method is described to prepare a Mo containing supported catalyst comprising TeO2 as active promoter and a process for preparing methanethiol in the presence of said catalyst.
摘要:
A method for preparing α-keto acids, especially α-ketomethionine, and/or derivatives thereof, whereby an aldehyde is reacted with thiols to give a corresponding dithioacetal, the dithioacetal formed, is reacted with an electrophile in the presence of a strong base, and the resulting α,α-(dithio)carboxylic acid is solvolyzed with acid-catalysis to release thiol and give the α-keto acid or a derivative thereof. Umpolung of aliphatic or aromatic aldehydes is effected by reaction with thiols.
摘要:
Disclosed herein are cyanide-tolerant nitrile hydratases especially from Pseudomonas putida or Pseudomonas marginalis strains which exhibit increased cyanide tolerance. Also disclosed are methods of preparing amides from nitriles in the presence of cyanides and polynucleotide sequences coding for cyanide-tolerant nitrile hydratases.
摘要:
A process for regenerating a catalyst used in the preparation of acrolein from glycerol, which comprises tungsten compounds and has acidic properties and at least one promoter.
摘要:
Disclosed herein are cyanide-tolerant nitrile hydratases especially from Pseudomonas putida or Pseudomonas marginalis strains which exhibit increased cyanide tolerance. Also disclosed are methods of preparing amides from nitriles in the presence of cyanides and polynucleotide sequences coding for cyanide-tolerant nitrile hydratases.
摘要:
The present invention refers to a catalyst for the manufacture of methyl mercaptan from carbon oxides comprising Mo and K compounds and oxides or sulfides of metals chosen from the manganese group. The improvement of the present process consists of the fact that carbon dioxide can be converted with higher conversions and selectivities to methyl mercaptan as compared to state-of-the-art technologies, with only minor amounts of carbon monoxide being formed as side product. Simultaneously, carbon monoxide can be easily converted into carbon dioxide and hydrogen by reaction with water using established water-gas-shift-technologies thus increasing the overall selectivity to methyl mercaptan.
摘要:
Disclosed herein are cyanide-tolerant nitrile hydratases especially from Pseudomonas putida or Pseudomonas marginalis strains which exhibit increased cyanide tolerance. Also disclosed are methods of preparing amides from nitriles in the presence of cyanides and polynucleotide sequences coding for cyanide-tolerant nitrile hydratases.