Abstract: The invention provides a nickel/silica catalyst optionally also containing cations of a lower Group II metal (X), which catalyst satisfies the following combination of features:1) a molar ratio of SiO.sub.2 /Ni=0.15-0.352) a molar ratio of X/Ni=0-0.153) an active nickel surface area above 120 m .sup.2 /g4) a BET surface area of which at least 40% is found with pores with a radius above 2.5 nm. Preferably the catalyst has an atomic X/Ni ratio between 0.05-0.10 and a BET surface area of which at least 45% is found in pores having a pore radius of above 2.5 nm. The group II metal X is preferably magnesium or barium.

Abstract: The invention provides a metal (Z=27-29)/alumina catalyst with an atomic ratio of active metal to aluminum between 12 and 1.5, having an active metal content of at least 75% in the activated catalyst, an active metal surface area between 60 and 150 m.sup.2 /g of metal, characterized in that the soyabean selectivity is below 2%, preferably below 1%.The invention also provides a process for the preparation of these catalysts and a method for the hydrogenation of saturated organic compounds using the catalyst.

Abstract: The invention provides catalysts suitable for hydrotreatment of mineral oil which contain an oxide and/or sulphide derived from a metal of Group VI (B) and one from Group VIII metal and a transition alumina and which show an oxygen chemisorption above 185 micromoles per gram, preferably between 200 and 300. Preferably tha catalysts are free from anions of strong mineral acids.These catalysts can be prepared by impregnation of a transition alumina with an ammoniacal metal solution having an initial pH between 10.5 and 13, preferably between 11.0 and 12.5.

Abstract: The invention provides new catalysts, useful for various hydrogenation reactions, which consist of 5 to 40% (w/w) of nickel upon a transition alumina, in particular gamma alumina support. These catalysts have an active nickel surface area of between 80 and 300, preferably 100-250 m.sup.2 /g of nickel and the nickel crystallites have an average diameter of 1 to 5, preferably 1.5 to 3 nanometers. The nickel crystallites are dispersed for at least 95% in the pores of the alumina.