Abstract: 1,4-Diacyloxybut-2-enes and 3,4-diacyloxybut-1-enes are converted into one another in the gas phase or liquid phase at from 100.degree. to 350.degree. C. under atmospheric or superatmospheric pressure in the presence of a zeolite as a catalyst.

Abstract: 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.

Abstract: Acyloxy-2-butenes of the formula ##STR1## where R.sup.1, R.sup.3 and R.sup.4 are each hydrogen or alkyl of 1 to 5 carbon atoms, R.sup.2 is alkyl of 1 to 5 carbon atoms, R.sup.5 is hydrogen, alkyl of 1 to 5 carbon atoms or R.sup.6 --CO--O, and R.sup.6 and R.sup.7 are each hydrogen, alkyl of 1 to 5 carbon atoms, phenyl or cyclohexyl, the preparation of these acyloxy-2-butenes by reaction of 1-acyloxy-1,3-butadienes of the formula ##STR2## with carboxylic acids of the formula R.sup.7 --COOH and oxygen at 50.degree.-180.degree. C. in the presence of catalysts containing palladium or platinum, and the use of the compounds of the formula I, where R.sup.1, R.sup.3, R.sup.4 and R.sup.5 are hydrogen, R.sup.2 and R.sup.6 are methyl and R.sup.7 is methyl or ethyl, for the preparation of 4-acyloxytiglic aldehydes.

Abstract: 2-Methylalk-2-enals of the formula ##STR1## where R.sup.1 and R.sup.2 are each hydrogen, alkyl or an aromatic radical, are prepared by isomerization of an acrolein derivative of the formula ##STR2## with a zeolite catalyst, an aluminum silicate and/or an aluminum phosphate.

Abstract: 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.

Abstract: .omega.,.omega.-Diacyloxy-2,6-dimethyl-octatrienoates and -octatrienals, as novel bifunctional asymmetric C.sub.10 building blocks for terpene syntheses, which possess a formyl or alkoxycarbonyl group at one chain end and 2 geminal acyloxy groups at the other, and a process for their preparation from readily obtainable industrial C.sub.5 building blocks and their use for the synthesis of terpene compounds by carbonyl olefination under conventional conditions.

Abstract: Acyloxyalkadienoates of the formula ##STR1## where R.sup.1, R.sup.2, R.sup.3, R.sup.6 and R.sup.7 are each hydrogen or a hydrocarbon radical, and R.sup.1 may furthermore be R.sup.6 --O--CO--, R.sup.4 is hydrogen or a hydrocarbon radical, but may only be hydrogen if x is 0, R.sup.5 is hydrogen, or is ##STR2## if x is 0, and x is 0 or 1, and their preparation.

Abstract: 2-alkyl-4,4-diacyloxybut-2-enals of the formula ##STR1## where R.sup.1 is alkyl and R.sup.2 and R.sup.3 are each hydrogen or an aliphatic, cycloaliphatic or aromatic radical, are prepared by a process wherein a 2-alkyl-2,4-diacyloxybut-3-enal of the formula ##STR2## is treated with an aliphatic carboxylic acid.

Abstract: But-2-ene-1,4-diones substituted in the 1,4-positions, of the formula ##STR1## where R.sup.1 and R.sup.2 are each an aliphatic hydrocarbon radical of 1 to 17 carbon atoms, are prepared by a process in which a 2,5-disubstituted furan of the formula ##STR2## where R.sup.1 and R.sup.2 have the above meaning, is oxidized with a percarboxylic acid in the presence of a carboxylic acid.

Abstract: 2-Alkyl-2,4-diacyloxy-but-3-enals of the formula ##STR1## where R.sup.1 is alkyl and R.sup.2 is hydrogen, alkyl, a cycloaliphatic radical or an aromatic radical, are prepared by reacting a buta-1,3-diene of the formula ##STR2## with an oxygen donor. The new compounds are valuable intermediates in the preparation of terpenes, e.g. retinal, .beta.-carotin and apocarotinoids.

Abstract: 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.

Abstract: A process for preparing diacyloxyalkadienes of the formula ##STR1## where R.sup.1 to R.sup.6 are each hydrogen or a hydrocarbon radical, which contain one or more hydrocarbon radicals having one or more non-conjugated double bonds, by reacting an aliphatic triene of the formula ##STR2## in which R.sup.1 to R.sup.6 have the same meanings given above with a carboxylic acid of the formulaR.sup.7 -COOHin which R.sup.7 has the same meaning given above, in the presence of a catalyst which contains palladium, platinum or salts of these metals and in the presence of oxygen.

Abstract: A process for the preparation of a diacyloxyhexadiene of the formula ##STR1## where X is R.sup.9 -CO- and R.sup.1 to R.sup.9 are hydrogen or alkyl of 1 to 3 carbon atoms, by reacting a hexatriene of the formula ##STR2## with oxygen and a carboxylic acid of the formula R.sup.9 COOH in the presence of a catalyst which contains palladium, platinum or a salt of these metals.

Abstract: A process for the preparation of .alpha.,.beta.-unsaturated aldehydes by reacting a 1,4-diacyloxyalk-2-ene, which is substituted in the 2-position by an aliphatic radical, with water in the presence of an acid, and of 2,7-dimethylocta-2,6-dienal.

Abstract: 3-Alkyl-3-acyloxy-4-hydroxybut-1-enes are prepared by a process in which a 3-alkyl-3,4-epoxybut-1-ene is treated with a carboxylic acid and a copper salt of a carboxylic acid.

Abstract: O-xylene and ethylbenzene are prepared by converting, 2,7-octadien-1-ol, 1,7-octadien-3-ol or mixtures containing these octadienols, or carboxylates of 2,7-octadien-1-ol or of 1,7-octadien-3-ol, or mixtures containing these carboxylates at from 200.degree. to 550.degree. C. over a catalyst.

Abstract: 2-Alkyl-4,4-diacyloxybut-2-enals of the formula ##STR1## where R.sup.1 is alkyl and R.sup.2 and R.sup.3 are each hydrogen or an aliphatic, cycloaliphatic or aromatic radical, are prepared by a process in which a 2-alkyl-1,4-diacyloxybuta-1,3-diene of the formula ##STR2## is reacted with oxygen or an oxygen donor, in the presence of a carboxylic acid of the formulaR.sup.3 -COOH III.

Abstract: 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.

Abstract: A process for reactivating supported catalysts which contain palladium, copper and tellurium and which are used for the acyloxylation of unsubstituted or substituted butadiene to give butenediol esters, wherein the supported catalysts are heated at from 200.degree. to 900.degree. C. in the presence of a gas which is inert under these treatment conditions.

Abstract: 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.