Abstract: A improved process is provided for the alkylation of aromatic compounds under at least partial liquid phase conditions, and in the presence of a zeolite-type alkylation/transalkylation catalyst. In accordance with the present process, a diluted aromatic hydrocarbon feedstock containing C.sub.5 -C.sub.7 olefins is brought into contact with a diluted olefinic feedstream in the presence of the alkylation/transalkylation catalyst. Prior to contact with the olefinic feedstream, C.sub.5 -C.sub.7 olefins present in the aromatic hydrocarbon feedstock are selectively hydrogenated.

Abstract: Alkylaromatic hydrocarbons are dehydrogenated into alkenylaromatic hydrocarbons by contacting them in the absence of molecular oxygen with a supported catalyst of the redox type wherein the metal in the catalyst is at a valency such that it is not in its most reduced state, and the catalyst is regenerated before being contacted with fresh feed.

Abstract: Process for producing gasolines having improved RON and MON which consists in subjecting the LCO, HCO and CLO obtained by catalytic cracking of a heavy hydrocarbon feedstock, to a hydrogenation treatment and subjecting the obtained products to a new catalytic cracking and then recovering hydrocarbons boiling in the range of gasolines.

Abstract: A process is disclosed for eliminating waxy paraffins from hydrocarbon feedstocks having an initial boiling temperature above about 180.degree. C. and containing sulphur, by selective cracking of the straight chain paraffinic hydrocarbons, said process comprising passing said feedstock over a crystalline silica polymorph of the silicalite type under suitable operating conditions for cracking the straight chain paraffins.

Abstract: Alkynes are selectively hydrogenated in alkene rich hydrocarbon feeds, such as 1,3-butadiene-rich C.sub.4 cuts, by passing the hydrocarbon feed at least partially in liquid phase over a palladium-based catalyst in the presence of hydrogen, preferably in trickle mode, followed by passing the effluent, at least partially in liquid phase preferably containing about 300-400 ppmw alkynes, over a copper-based catalyst in the presence of hydrogen thereby producing a hydrocarbon product of significantly reduced alkyne concentration.

Abstract: A process for the treatment of a gas oil fraction to produce a lighter fraction useful as diesel fuel and/or gasoline comprising subjecting the gas oil fraction to dewaxing and mild hydracracking treatments. The dewaxing is carried out over a silicalite dewaxing catalyst. The dewaxing and mild hydrocracking treatments may be carried out sequentially or simultaneously. The gas oil feed may be passed successively through a silicalit-catalyst bed, a bed of hydrotreating catalyst and a bed of hydrocracking catalyst.

Abstract: A process for removing the basic nitrogen compounds from gas oils comprises treating the gas oils with a homogeneous solvent mixture comprising a diluted aqueous acid solution and an alcohol having from 1 to 6 carbon atoms, the volume ratio of alcohol to diluted aqueous acid solution being between 90/10 and 10/90, the volume ratio of solvent mixture to gas oils being between 0.5 and 5.