Abstract: The invention relates to a catalyst that contains at least one matrix, a partially amorphous Y zeolite, optionally at least one metal that is selected from the group that is formed by the metals of group VIB and group VIII of the periodic table, optionally at least one element that is selected from the group that is formed by phosphorus, boron and silicon, optionally at least one element of group VIIA, and optionally at least one element of group VIIB. The partially amorphous Y zeolite has a peak rate that is less than 0.4, and a crystalline fraction that is expressed relative to a reference zeolite in sodium form and that is less than 60%. The invention also relates to the use of this catalyst in hydroconversion, in particular hydrocracking and hydrorefining of hydrocarbon feedstocks.

Abstract: The invention concerns a process for regenerating an impure catalyst comprising sulphuric acid deposited on silica.It is characterized in that the catalyst is calcined at least once to eliminate organic hydrocarbon substances contained in the catalyst, in particular as a result of its use in aliphatic alkylation reactions.

Abstract: The present invention relates to a catalyst comprising silica and sulphuric acid which impregnates said silica, and the use of said catalyst in catalytic alkylation of isobutane and/or isopentane in the presence of at least one olefin containing 3 to 6 carbon atoms per molecule, said catalyst being characterized in that the silica, prior to its impregnation with sulphuric acid, has a total porous volume greater than 1.5 cm.sup.3 per gram and in that said catalyst consists essentially of particles of an average diameter of between 0.1 and 150 .mu.m.

Abstract: The present invention relates to a catalyst comprising silica and an acid phase comprising sulphuric acid and the compound HB(HSO.sub.4).sub.4, the silica having been impregnated by said acid phase, said catalyst being such that is consists essentially of particles of an average diameter of between 0.1 and 150 .mu.m, its content by weight of acid phase is greater than 40%, the silica, prior to its impregnation with said acid phase, has a total porous volume of between 0.5 and 6 cm.sup.3 per gram and said acid phase contains between 0.4% and 68.8% by weight of the compound HB(HSO.sub.4).sub.4, said acid phase containing neither sulphuric anhydride nor boric acid.The invention also relates to the preparation and use of said catalyst in catalytic alkylation of isobutane and/or isopentane in the presence of at least one olefin containing 3 to 6 carbon atoms per molecule.

Abstract: The present invention relates to a catalyst comprising silica and an acid phase comprising sulphuric acid and the compound HB(HSO.sub.4).sub.4, the silica having been impregnated by said acid phase, said catalyst being such that is consists essentially of particles of an average diameter of between 0.1 and 30 .mu.m, prior to its impregnation with said acid phase, has a total porous volume of between 0.1 and 6 cm.sup.3 per gram and said acid phase contains between 0.4% and 68.8% by weight of the compound HB(HSO.sub.4).sub.4, and between 31.2% and 99.6% by weight of the compound containing neither sulphuric anhydride nor boric acid.The invention also relates to the preparation and use of said catalyst in catalytic alkylation of isobutane and/or isopentane in the presence of at least one olefin containing 3 to 6 carbon atoms per molecule.