摘要:
1,4-diacyloxybutenes are prepared by reacting a 1,3-butadiene with a carboxylic acid and oxygen in the presence of a catalyst in a reactor, by a process in which the 3,4-diacyloxybutene formed as a by-product in the reaction is separated off from the reaction mixture, and some or all of this 3,4-diacyloxybutene is recycled to the reactor.
摘要:
A catalyst containing copper and silica is prepared by a process in which an aqueous alkali metal silicate solution containing from 1 to 26% by weight of SiO.sub.2 is brought to a pH of from 0.5 to 2.0 with nitric acid, an aqueous copper nitrate solution containing from 5 to 15% by weight of Cu is added, after the addition of the nitric acid, so that a clear solution containing from 0.18 to 3.0 moles of Cu per mole of SiO.sub.2 is formed, the resulting solution is mixed with an aqueous alkali metal carbonate solution at from 40.degree. to 80.degree. C., the pH of the mixture being kept at from 7.5 to 8.5, and the precipitated material is separated off, dried, calcined by heating at from 250.degree. to 400.degree. C. and pressed in a conventional manner to give catalyst moldings. The catalyst thus obtained is used for the hydrogenation of dialkyl dicarboxylates to diols.
摘要:
A process for regenerating a supported catalyst for acyloxylations, which contains palladium and/or platinum and tellurium, with or without copper, wherein copper is applied to the catalyst to be regenerated.
摘要:
Butane-1,4-diol is prepared by catalytic hydrogenation of dibutyl succinate by a process in which hydrogenation is terminated before complete conversion is reached, butanol is distilled off from the reaction mixture, the liquid distillation residue is cooled to below 108.degree. C., the upper phase, which is formed as a result of phase separation and essentially consists of dibutyl succinate, is recycled to the hydrogenation, and the butane-1,4-diol is obtained from the lower phase, which essentially consists of this compound, by fractional distillation under reduced pressure.
摘要:
A process for the preparation of butenediol diacetate by reacting butadiene with oxygen and acetic acid or with a compound which liberates acetic acid under the reaction conditions, over a solid catalyst which contains a platinum metal and one or more elements of main group 5 or 6, in the presence of butanediol diacetate, butanediol monoacetate, butanediol or a mixture of these, and the use of the butenediol diacetate, thus obtained, to prepare butane-1,4-diol by hydrogenating and then hydrolyzing the diacetate.
摘要:
A process for the preparation of butane-1,4-diol by catalytic hydrogenation of a mixture obtained by treating maleic anhydride with an aliphatic alcohol at elevated temperatures, wherein a monohydric or dihydric aliphatic alcohol of boiling point above 180.degree. C. is used and the mixture of maleic acid and the alcohol is obtained by washing a gaseous reaction mixture, which contains maleic anhydride and is obtained in the catalytic oxidation of hydrocarbons by air, with the alcohol.
摘要:
Cyclohexyl hydroperoxide containing reaction mixtures obtained by oxidation of cyclohexane with molecular oxygen or molecular oxygen containing gases in the liquid phase at from 130.degree. to 200.degree. C. and under from 5 to 125 bar are worked up by reaction with cycloolefins at elevated temperature in the presence of catalysts to react cyclohexyl hydroperoxide with cyclohexene at elevated temperatures in the presence of cyclohexene-soluble compounds of transition metals of groups 4 or 5 or 6 of the periodic table or of one or more cyclohexane-insoluble compounds of a transition metal of group 4 or 5 or 6, or in the presence of selenium, tellurium or a boride, and the resulting cyclohexene oxide at elevated temperatures to cyclohexanol in the presence of hydrogenation catalysts.
摘要:
Solutions of molecular oxygen in liquid hydrocarbons are prepared by bringing a liquid hydrocarbon into contact with molecular oxygen under superatmospheric pressure in a vertical absorption zone, by a process in which(a) a layer of water is maintained at the lower end of the absorption zone,(b) molecular oxygen is passed into the layer of water,(c) a liquid hydrocarbon is fed in above the layer of water,(d) the finely divided molecular oxygen rising from the layer of water is passed upward together with the liquid hydrocarbon at from 0.degree. to 50.degree. C., with thorough mixing in the absorption zone, with the proviso that no cohesive gas phase is formed, and(e) the solution of molecular oxygen in the liquid hydrocarbon is discharged in the upper part of the absorption zone.
摘要:
Maleic anhydride is separated off from gaseous reaction mixtures by a continuous process in which the gaseous reaction mixture containing the maleic anhydride is brought into contact with butanol, the gaseous substances obtained in this procedure are brought into contact with butyl maleate by a countercurrent method, and the liquid product is removed from the bottom.