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:
This invention relates to a process for the production of primary and/or secondary amines from oxo compounds by catalytic imination of the oxo compound with ammonia or a primary amine and subsequent hydrogenation. Imination proceeds according to the invention in the presence of a novel imination catalyst, namely an organopolysiloxane containing sulphonate groups. This imination catalyst is distinguished by elevated activity. The process is in particular suitable for the production of isophorone diamine from isophorone nitrile, wherein it has proved possible to reduce the content of secondary products and to increase yield.
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:
3-Hydroxypropanal is prepared by reacting acrolein with water under pressure and in the presence of an ion exchange resin while adding a carboxylic acid to the reaction mixture.
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 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.
摘要:
A process for the working up of a product stream from the epoxidation of olefins that contains olefin, olefin oxide, water-miscible organic solvent and water, by separating this product stream into an overhead product containing olefin, olefin oxide and organic solvent, and into a bottom product containing organic solvent and water, wherein the separation takes place in a pre-evaporator with less than 10 theoretical separation stages at a pressure of 1.5 to less than 3 bar, and 20 to 60% of the total amount of organic solvent introduced with the product stream is removed with the overhead product and the balance remains in the bottom product. A process for the epoxidation of olefins that includes this working up stage is also disclosed.
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 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.