摘要:
Impurities are separated from aqueous solutions of 1,6-hexanediol or 1,6-hexanediol precursors, such as adipic and 6-hydroxycaproic acid, by a process which comprises adding at least one carboxylic acid to a solution (a) of 1,6-hexanediol and subjecting this solution (a) or a solution (b) containing carboxylic acid(s) as precursor(s) of 1,6-hexanediol to a heat treatment at temperatures above room temperature in the absence of hydrogen.
摘要:
A process for the continuous production of cyclohexene from a cyclohexyl ester of a carboxylic acid having 1 or 2 carbon atoms, which comprises the following steps:a) heating a cyclohexyl ester of a carboxylic acid having 1 or 2 carbon atoms in the presence of an acid catalyst with the formation of cyclohexene and a carboxylic acid having 1 or 2 carbon atoms;b) removing, by distillation, cyclohexene and carboxylic acid having 1 or 2 carbon atoms from the reaction mixture from stage a) at the same rate as they are formed;c) adding a cyclohexyl ester of a carboxylic acid having 1 or 2 carbon atoms to stage a) at the rate cyclohexene and carboxylic acid are distilled off; andd) separating the mixture comprising cyclohexene and carboxylic acid having 1 or 2 carbon atoms coming from stage b).
摘要:
The present invention relates to a process for preparing diols by hydrogenating a mixture comprising carboxylic acid, carboxylic anhydrides and/or carboxylic esters/lactones by means of a cobalt-comprising catalyst, wherein alkali metal and/or alkaline earth metal ions are added to the hydrogenation feed, excluding alkali metal and/or alkaline earth metal ions of mineral acids.
摘要:
In a process for the catalytic hydrogenation of 2,5- and 2,3-dihydrofuran with hydrogen to give tetrahydrofuran, use is made of a catalyst in which a metal or a plurality of metals have been deposited by vapor deposition or sputtering on a metal wire mesh or a metal foil as support.
摘要:
In a process for preparing aliphatic alcohols by hydrogenating aliphatic carboxylic acids or anhydrides or esters thereof or lactones in the presence of a catalyst comprising Pt and Re, in the form of the metal or an oxide in each case, the catalyst further comprises at least one further element from the groups 5 to 12 and 14 and the lanthanides of the Periodic Table of the Elements in the form of the metal or an oxide.
摘要:
A process for preparing tetrahydrofuran, which comprises reacting 1,4-butenediol diethers of the formulae I and/or II RO—CH2—CH═CH—CH2—OR I RO—CH2—CH2═CH—CH2—OR II, where the R radicals can be identical or different and are C1-C15-alkyl or cycloalkyl radicals, C6-C12-aryl radicals or C7-C15-aralkyl radicals, with water and hydrogen at from 20 to 300° C. under from 1 to 300 bar in the presence of catalysts or catalyst combinations which comprise components which are both capable of hydrogenation and have acidic or basic centers and a novel process for preparing 1,4-butanediol diethers of the formula I by metathesis are described.
摘要:
A process for preparing cyclopentyl formates of the formula (II) ##STR1## by reacting cyclopentenes of the formula (I) ##STR2## where R.sup.1, R.sup.2 and R.sup.3, independently of one another, are hydrogen atoms or C.sub.1-8 -alkyl,with formic acid in the presence of an acid catalyst.
摘要:
A process for the preparation of .gamma.-butyrolactone, in which 2,5-dihydrofuran or 2,3-dihydrofuran or a mixture of these two dihydrofurans is caused to react in the gas phase in the presence of water and in the presence or absence of additional hydrogen at elevated temperature over a hydrogenating catalyst.
摘要:
A process for the preparation of polyoxyalkylene glycols or polyoxyalkylene glycol copolymers from polyoxyalkylene glycol formates or the formates of polyoxyalkylene glycol copolymers comprises reacting the formates of polyoxyalkylene glycols or of polyoxyalkylene glycol copolymers in the liquid phase in the presence of a heterogeneous catalyst which contains, as catalytically active component, rhenium and/or at least one element from sub-group VIII of the Periodic Table of the Elements.
摘要:
In a process for preparing GBL by reaction of 1,4 butanediol over a copper catalyst, use is made of a 1,4 butanediol-containing reaction mixture which comprises further alcohols other than 1,4-butanediol and water.