摘要:
The invention relates to a process for increasing the selectivity of the hydrogenation of 4,4′-diaminodiphenylmethane (4,4′-MDA) to diaminodicyclohexylmethane (4,4′-HMDA) by catalytic hydrogenation of a mixture containing 4,4′-MDA as the main component and its mono-N-methyl derivative as a secondary component. According to the invention, the hydrogenation is terminated before a conversion of 4,4′-MDA to 4,4′-HMDA of 99% is achieved. Under these conditions, a substantially smaller proportion of the N-methyl-4,4′-MDA is hydrogenated to N-methyl-4,4-HMDA.
摘要:
The invention relates to a process for increasing the selectivity of the hydrogenation of 4,4′-diaminodiphenylmethane (4,4′-MDA) to diaminodicyclohexylmethane (4,4′-HMDA) by catalytic hydrogenation of a mixture containing 4,4′-MDA as the main component and its mono-N-methyl derivative as a secondary component. According to the invention, the hydrogenation is terminated before a conversion of 4,4′-MDA to 4,4′-HMDA of 99% is achieved. Under these conditions, a substantially smaller proportion of the N-methyl-4,4′-MDA is hydrogenated to N-methyl-4,4-HMDA.
摘要:
A process for the continuous epoxidation of propene with hydrogen peroxide in the presence of a titanium silicalite catalyst and a methanol solvent, wherein the catalyst is periodically regenerated by washing with a methanol solvent at a temperature of at least 100° C. and the epoxidation reaction is carried out for periods of more than 300 h between two regeneration steps.
摘要:
A process for the epoxidation of olefins which includes i) reacting an olefin with hydrogen peroxide in presence of an epoxidation catalyst and an alcoholic solvent; ii) separating product olefin oxide and unreacted olefin from the reaction product of step i); iii) recovering a stream comprising the alcoholic solvent; and iv) subjecting the recovered stream of step iii) to hydrogenation.
摘要:
A continuous process for the epoxidation of olefins with hydrogen peroxide in the presence of a heterogeneous catalyst promoting the epoxidation reaction, whereby the aqueous reaction mixture contains i) an olefin; ii) hydrogen peroxide; iii) less than 100 wppm of alkali metals, earth alkali metals, both irrespective whether in ionic, complex or covalently bonded form, bases or cations of bases having a pkB of less than 4.5, or combinations thereof; and, iv) at least 100 wppm of bases or cations of bases having a pkB of at least 4.5 or combinations thereof, whereby the wppm are based on the total weight of hydrogen peroxide in the reaction mixture.
摘要:
A process for the catalytic epoxidation of olefins in the presence of a titanium containing zeolite catalyst and a polar solvent whereby the deactivation of the catalyst upon recycling of the solvent has been considerably reduced. In the process one or more nitrogen containing compounds are introduced at some stage, a solvent stream is recovered, treated to contain less than 50 wppm nitrogen in the form of organic nitrogen compounds and at least a part of it is recycled to the epoxidation step. Also disclosed is a process for the catalytic epoxidation of propene which integrates the treatment and recycle of the solvent into the workup of the reaction mixture.
摘要:
A process for the production of primary and/or secondary amines from imines or nitriles, comprising an aminating hydrogenation of imine or of nitrile with hydrogen in the presence of ammonia, of a hydrogenation catalyst based on cobalt, nickel, ruthenium or mixtures of these metals and of a base, at a temperature within the range of 50.degree. C. to 200.degree. C. and at a pressure within the range of 0.3 to 30 MPa. The yield of amine is increased by the use of a quaternary ammonium hydroxide as base. Preferably a tetraalkylammonium hydroxide is used in a quantity of from 0.01 to 100 mMol per mol of amine or of nitrile. The process is suitable in particular for the production of isophoronediamine from isophorone nitrile imine.
摘要:
A two-stage process for producing 1,3-propanediol by first hydrogenating at a temperature of 30° C. to 80° C. in the presence of an oxide-supported metal hydrogenation catalyst. Second, the resulting reaction solution is hydrogenated at a temperature of 80° C. to 180° C. to a 3-hydroxypropanal conversion of substantially 100% in the presence of an activated carbon-supported metal hydrogenation catalyst.
摘要:
The present invention provides an improved process for the hydrogenation of 3-hydroxypropanal to 1,3-propanediol which comprises purifying an aqueous solution of 3-hydroxypropanal by contacting said aqueous solution with a purifying agent prior to hydrogenation.
摘要:
A process for recovering methanol from mixtures containing methanol and water, comprising multistage evaporation with heat integration, wherein the pressure is reduced from each stage to the next, and a downstream series of distillation stages with heat integration, wherein the pressure is increased from each stage to the next. The process reduces the amount of energy required for methanol recovery.