摘要:
The present invention relates to a method for synthesis of 2,2,6-trimethylcyclohexan-1-one (TMCH) by partial reduction of 2,6,6-trimethyl-2-cyclohexen-1,4-dione (ketoisophorone, KIP), the reaction being carried out in the gas phase in the presence of oxide catalysts.
摘要:
A process for the preparation of 3,5,5-trimethylcyclohexa-3-en-1-one (&bgr;-isophorone) by isomerization of 3,5,5-trimethylcyclohexa-2-en-1-one (&agr;-isophorone) in the liquid phase in the presence of a salt-like or organometallic catalyst. By using catalytic quantities of alkali-metal salts or alkaline-earth salts and/or their organometallic compounds, and without addition of a further auxiliary substance, the space-time yield in the preparation of &bgr;-isophorone is high. &bgr;-Isophorone is particularly suitable as an intermediate product for the preparation of ketoisophorone.
摘要:
A method for the isolation of 2-hydroxy-4-methylthiobutyric acid (MHA), wherein MHA is isolated from a reaction mixture obtained by addition of hydrogen cyanide (HCN) to methylmercaptopropionaldehyde (MMP) and hydrolysis by sulphuric acid of the methylmercaptopropionaldehyde cyanohydrin (MMP-CH) thus obtained. The reaction mixture is brought into contact in a liquid/liquid extraction system with an organic solvent substantially immiscible with water, in order to form an extraction solution which contains the solvent and the MHA transferred out of the reaction mixture. By bringing the salt content of the reaction mixture, prior to the liquid/liquid extraction, to a concentration of about >50 wt. % (wt./wt.), preferably >55 wt. %, referred to the sum of the inorganic constituents of the reaction mixture, the coordinated use of energy in the total system is improved, the evaporation of strongly corrosive solutions is avoided, the efficiency of the hydrolysis step is increased and the distribution coefficients during the extraction are improved. The MHA is isolated as the extract from this extraction solution by evaporation, and may be used as animal feed supplement.
摘要:
A process for the preparation of methionine or a salt of methionine by reaction of the components 3-methylmercaptopropionaldhyde, hydrogen cyanide, ammonia and carbon dioxide or components from which the above-mentioned components can be prepared, optionally in the presence of water, to 5-(2-methylmercaptoethyl)-hydantoin and further reaction thereof to methionine or the salt thereof, characterised in that the reaction of the components is initiated by means of at least one premixture in such a way that a first mixture is formed containing at least the predominant proportion (at least 5/10) of the 3-methylmercaptopropionaldeyde and at least 1/10 of the hydrogen cyanide component or corresponding quantities of components from which these components can be prepared, and less than 5/10 of one of the components ammonia, carbon dioxide or of the components from which ammonia or carbon dioxide can be prepared, and in that this first mixture is combined with the other component(s) for the reactive conversion to 5-(2-methylmercaptoethyl)-hydantoin, wherein this (these) latter component(s) may be premixed in one or more other mixtures.
摘要:
An improved process for the production of 2,3,5-trimethylhydroquinone by rearrangement of 4-oxoisophorone (ketoisophorone, 3,5,5-trimethyl-2-cyclohexen-1,4-dione) to yield a trimethylhydroquinone diester and the subsequent saponification thereof. Trimethylhydroquinone is in turn an important starting material for the production of vitamin E.
摘要:
A method of producing 3,5,5-trimethylcyclohexa-3-ene-1-one (.beta.-isophorone) by isomerization of 3,5,5-trimethylcyclohexa-2-ene-1-one (.alpha.-isophorone) in a liquid phase in the presence of a homogeneous or heterogeneous catalyst in which a mixture with a relatively low concentration of .beta.-isophorone is drawn off from the reaction container and the .beta.-isophorone isolated by vacuum distillation. .beta.-isophorone is an important synthetic structural element for the production of carotinoids, vitamins and pharmaceutical products.
摘要:
A process for the preparation of methionine or a salt of methionine by reaction of the components 3-methylmercaptopropionaldhyde, hydrogen cyanide, ammonia and carbon dioxide or components from which the above-mentioned components can be prepared, optionally in the presence of water, to 5-(2-methylmercaptoethyl)-hydantoin and further reaction thereof to methionine or the salt thereof, characterised in that the reaction of the components is initiated by means of at least one premixture in such a way that a first mixture is formed containing at least the predominant proportion (at least 5/10) of the 3-methylmercaptopropionaldeyde and at least 1/10 of the hydrogen cyanide component or corresponding quantities of components from which these components can be prepared, and less than 5/10 of one of the components ammonia, carbon dioxide or of the components from which ammonia or carbon dioxide can be prepared, and in that this first mixture is combined with the other component(s) for the reactive conversion to 5-(2-methylmercaptoethyl)-hydantoin, wherein this (these) latter component(s) may be premixed in one or more other mixtures.
摘要:
The invention relates to the production and purification of salts of 6,8-bis(amidiniumthio) octanoic acid, its enantiomers (+)-6,8-bis(amidiniumthio)octanoic acid and (-)-6,8-bis (amidiniumthio)octanoic acid and of the esters of these compounds as well as to their use to produce dihydrolipoic acid and .alpha.-lipoic acid.
摘要:
The direct saponification of methionine nitrile obtained from methylmercaptopropionaldehyde, prussic acid and ammonia gives low yields, catalyst and educt losses and unwanted side-products. The aim of the invention is therefore to provide a method which can be carried out without isolating the intermediate products, in particular continuously, and with low losses. The ketone used is recovered in high yields after amide saponification since this liberates the ketone from side-products. In order to recover the ammonia, it is necessary for the ammonia to be substantially freed of ketone, the mixture of ammonia, ketone and water obtained being separated under pressure in a separation column. When the amide is saponified at .gtoreq.160.degree. C., amide concentrations of less than 25% by wt. are preferred. Methionine nitrile is produced by treatment with at least 4 equivalents of .gtoreq.50% by wt. ammonia at between 40.degree. and 80.degree. C./or between 5 and 60 min. Cyanide residues are destroyed by heating to over 150.degree. C. Methionine is of particular use as a feedstuff, in particular in aqueous solution.