Abstract: Sulphones useful for preparing polyenes have the formula: ##STR1## where the sulphonyl group replaces a hydrogen atom on carbon atom (a) or (b), R represents alkyl, aralkyl or aryl, optionally substituted, A and Q represent an optionally substituted hydrocarbon of 5n+1 carbon atoms (n is 1-5), methyl, optionally substituted by halogen, sulphide or sulphone, CH.sub.2 OH (or an ether or ester thereof), CHO (optionally protected), COOH (or an acid chloride, ester or nitrile thereof), with the proviso that when A represents a 2-(2,6,6-trimethylcyclohex-1-enyl) ethenyl radical, Q cannot represent --COOH or an ester thereof.

Abstract: Methylisobutylketone is produced from acetone in a high yield with a good selectivity through one-step reaction by contacting acetone together with at least one of water and hydrogen with an element of Group VIII of the periodic table, a halogen and a phosphorus compound as a catalyst under a super atmospheric pressure in a carbon monoxide atmosphere.

Abstract: Trickle-type fixed-bed catalytic reactions are improved, prior to starting or resuming an on-stream period, by purging air from the catalyst bed and reaction zone by downward flow of an inert gas therethrough, flooding the purged reaction zone by flowing a liquid upwardly through the catalyst bed to cover same, then removing the liquid and instituting the on-stream period by introducing gaseous and liquid reactants at the upper end of the catalyst bed to flow downwardly therethrough.

Abstract: A novel method for the selective preparation of the cis isomer of a disubstituted ethylenically unsaturated compound is proposed in which a disubstituted acetylenically unsaturated compound is partially hydrogenated in the presence of, in place of a conventional Lindlar catalyst or a combination of a Lindlar catalyst with an amine, a palladium catalyst borne on an alumina carrier in combination with water and a hydroxide or a basic salt of an alkali metal or an alkaline earth metal. The inventive method is advantageous over conventional methods by the unnecessity of the use of an amine compound which is definitely undesirable when the product is directed to the application in perfumery and by the easiness in handling of the catalyst which can be easily separated from the reaction mixture after completion of the reaction.

Abstract: Process for hydrogenating unsaturated compounds in the liquid phase in the presence of a soluble catalyst obtained by reacting an organometal derivative or a metal hydride with a synergistic mixture of (a) a compound of zinc, zirconium, manganese, molybdenum, or iron and (b) a nickel or cobalt compound.

Abstract: Aliphatic carbonyl compounds are prepared by an aldol condensation of carbonyl compounds R.sup.1 --CH.sub.2 --CO--R.sup.2 (I; R.sup.1 and R.sup.2 =H or C.sub.1 -C.sub.8 -alkyl) in the presence of hydrogen and of a catalyst which has both condensing and hydrogenating properties, by using a catalyst system wherein the active components are from 1 to 90 percent by weight of a noble metal of group VIII of the periodic table and from 10 to 99 percent by weight of an oxide or salt of a rare earth metal, or of a mixture of different oxides and/or salts of rare earth metals.

Abstract: Carbonyl compounds R.sup.1 --CHR.sup.2 --CHR.sup.3 --CR.sup.4 O (I, R.sup.1 =H or an organic radical; R.sup.2 -R.sup.4 =H or C.sub.1 -C.sub.4 -alkyl) are prepared by selective hydrogenation of the .alpha.,.beta.-unsaturated carbonyl compounds R.sup.1 --CR.sup.2 =CR.sup.3 --CR.sup.4 O (II) in the liquid phase by means of hydrogen in the presence of a palladium catalyst and of from 15 to 50% by weight, based on (II), of a tertiary amine.

Abstract: Trickle-type fixed-bed catalytic reactions are improved, prior to starting or resuming an on-stream period, by purging air from the catalyst bed and reaction zone by downward flow of an inert gas therethrough, flooding the purged reaction zone by flowing a liquid upwardly through the catalyst bed to cover same, then removing the liquid and instituting the on-stream period by introducing gaseous and liquid reactants at the upper end of the catalyst bed to flow downwardly therethrough.