Abstract: The invention relates to a process for the synthesis of dibenzofuran by the dehydrocyclization of 2-cyclo-hexenyl-cyclohexanone at high temperature in the presence of air and a catalyst system selected among the known dehydrogenation catalysts.By the claimed process very high yields of dibenzofuran are achieved.

Abstract: A method for the preparation of a group of variously substituted ureas is disclosed, these compounds being obtained by the pyrolytic decomposition of the alkali metal or alkaline earth metal carbamates corresponding to the expected ureas, the reaction taking place at a temperature of between 150.degree. and 400.degree. C under atmospherical pressures, and preferably under subatmospherical pressures, under which conditions the expected urea either sublimes or is distilled.

Abstract: A process for the preparation of dialkylcarbonates by reacting an alcohol with a cyclic carbonate, wherein the reaction is carried out in the presence of an organic base, preferably a tertiary aliphatic amine, at a temperature of between 50.degree. and 150.degree. C and at a pressure of between 0.1 and 10 kg./sq.cm., the conversion of dialkylcarbonate being selective and avoiding the need of removing inorganic by-products.

Abstract: A method is disclosed for preparing complexes of metals of the VIII Group of the Periodic Table, useful as hydrogenation catalysts. The method, as a single-step process, comprises reacting a polymeric complex containing V Group elements and VIII Group metal compounds directly with a metal atom which is directly bound to the V group element in the presence of a reducing substance. The reducing substance is selected among alkali metal and alkaline earth metal hydrides, mixed alkaline-III group element hydrides, organic metallic compounds of III Group metals, alkali metal and alkaline earth metal alkyls, Grignard compounds.

Abstract: In the preparation of 4-chloro-2-methyl-crotonaldehyde, an important starting material for the preparation of the acetate of Vitamin A, the improvement consisting in that isoprene monoepoxide (1:2-epoxy-2-methyl-3-butene) is chlorinated either with tert.butyl hypochlorite in the vapor phase, or with cupric chloride in the liquid phase. The reaction is preferably carried out in an inert siliceous or aluminous substrate at temperatures ranging from 60.degree. C to 150.degree. C. Lithium chloride has proven to be useful as a catalyst, but by no means essential.

Abstract: The invention relates to a process for preparing diaryl carbonates starting from phenyl alkyl carbonates, the reaction being carried out in the presence of suitable catalysts capable of affording greater yields and selectivity; the catalyst system is selected amongst the Lewis acids or the compounds of transition metals.

Abstract: A method is disclosed for preparing salts of monoesters of the carbonic acid, the improvement consisting in that the alcohol corresponding to the monoester is reacted with carbon dioxide and a halide of a metal of the Groups IA, IIA, IIIA and IIB of the Periodic Table, the reaction being effected in the presence of a nitrogenous, aliphatic, aromatic or heterocyclic base.

Abstract: A method is disclosed for the preparation of thiocarbamic acid esters by reacting an aminic compound with carbon monoxide and an organic disulphide. Elemental selenium is used as the catalyst, possibly supplemented by a tertiary amine. The temperature and pressure ranges are comparatively wide.

Abstract: In waste-water-treatment, the improvement consisting in causing the precipitation of anionic pollutants by adding to the sewage an aqueous solution of a bis-triarylphosphonium salt. A number of different chemical formulas for such salts are disclosed. It becomes possible to recover dyestuffs from dyeing baths in the textile industries, while solving a severe pollution-preventing problem.