摘要:
A process for the preparation of &agr;-amino acids by hydrolysis of hydantoins in the presence of water and at least one metallic oxide under conditions such that all the starting materials are completely dissolved in the water as a result of high pressure and high temperature and only one further phase is present in the reactor in addition to the metallic oxide phase.
摘要:
The invention relates to a process for the preparation of D,L-methionine, in which carbon dioxide is fed 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, where, for the purposes of purification, an aqueous solution of the separated-off crude methionine is prepared and subjected to a recrystallization, characterized in that the solution from which the recrystallization takes place contains potassium ions and also a crystallization additive, where the crystallization additive is a nonionic or anionic surfactant, or a mixture of different nonionic or anionic surfactants, and that the recrystallization takes place by introducing a 60 to 110° C.-hot methionine solution into a 35 to 80° C.-warm methionine suspension, the temperature of which is lower than that of the introduced solution, the temperature of the methionine suspension being maintained between 35 and 80° C. during the addition.
摘要:
A chemical compound of the general formula I or II is useful as feed additive: wherein X=O or NR, and R=H, C1-C6-alkyl (optionally branched), C3-C6-cycloalkyl, aryl, or aralkyl, and wherein R1, R2, are identical or different and in each case H, C1-C6-alkyl (optionally branched), C3-C6-cycloalkyl, allyl, aryl, or aralkyl; or R1 and R2 together are an C2- to C6-alkylene group (optionally C1-C6-alkyl substituted).
摘要:
The invention relates to a method for production of D- and/or L-methionine via D- and/or L-homoserine with subsequent chemical transformation to give methionine.
摘要:
The present invention refers to a continuous process for the manufacture of methyl mercaptan using Mo—O—K-based catalysts. It is further described that the total selectivity of methylmercaptan can be increased by at least 1% by lowering the total gas hourly space velocity. The invention further refers to a process for the preparation of a solid, preformed catalyst system.
摘要:
The invention relates to a reaction vessel in which hydrogen sulphide is produced from sulphur and hydrogen, wherein the reaction vessel is partially or completely made up of a material which is resistant to the reaction mixture and its compounds and/or elements and which remains resistant even at high temperatures.
摘要:
The present invention relates to a sequence for the preparation of amino acids, for example alpha amino acids, in particular methionine, by making use of an amidocarbonylation reaction and reuse of the catalyst.
摘要:
The present invention relates to the preparation of α-hydroxy ketones of the general formula I. In particular, the invention relates to novel imidazolinium carboxylate adducts and to a novel process for using catalytic amounts of imidazolium and imidazolinium carboxylate adducts in the acyloin reaction of aldehydes to prepare hydroxy ketones of the general formula I, where R and R′ are the same or different and are each H or a straight-chain or branched and optionally substituted C1-C12-alkyl radical, and R″═H3CSCH2CH2, t-butyl, n-butyl, sec-butyl, n-propyl, i-propyl, an optionally heteroatom-substituted C6-C18-aryl, heteroaryl, C6-C18-arylalkyl, especially phenylmethyl, where phenyl may again be heteroatom-substituted, or heteroalkyl.