Abstract: A nickel/silica catalyst having a Ni/SiO.sub.2 molar ratio of 10 to 2.5, preferably 6 to 3, contains zinc in an amount of at least 500 ppm (based on the nickel) and maximally in a molar ratio Zn/SiO.sub.2 of 1. Additionally, the catalyst may comprise Mg in a molar ratio Mg/Ni of 0.05-0.15, max. (Mg+Zn)/Sio.sub.2 molar ratio is 1. Also the catalyst may comprise Al in a molar ratio Al/Si of 0.05-0.5. Also methods of preparing the catalyst and its use for hydrogenating oils and fats have been described.

Abstract: Zeolite L in very small crystalline form is prepared by a process in which an alkaline reaction mixture comprising water, a source of silicon (SiO.sub.2), a source of alkali metal (M) (KOH) and a source of aluminium (Al.sub.2 O.sub.3.3H.sub.2 O) or gallium is heated to a temperature of at least 80.degree. C. for a period of time long enough to form zeolite L, the composition of the reaction mixture having the following molar ratios (expressed as oxides):______________________________________ M.sub.2 O/SiO.sub.2 0.4 to 0.5 H.sub.2 O/M.sub.2 O 15 to 30 and SiO.sub.2 /Al.sub.2 O.sub.3 or Ga.sub.2 O.sub.3 5 to 11 ______________________________________where M is potassium or a mixture of potassium and one or more other alkali metals. Zeolite L made by this process can be used for separating isomers of dimethylnaphthalene from one another.

Abstract: Zeolite L in very small crystalline form is prepared by a process in which an alkaline reaction mixture comprising water, a source of silicon (SiO.sub.2), a source of alkali metal (M) (KOH) and a source of aluminium (Al.sub.2 O.sub.3.3H.sub.2 O) or gallium is heated to a temperature of at least 80.degree. C. for a period of time long enough to form zeolite L, the composition of the reaction mixture having the following molar ratios (expressed as oxides):______________________________________ M.sub.2 O/SiO.sub.2 0.4 to 0.5 H.sub.2 O/M.sub.2 O 15 to 30 and SiO.sub.2 /Al.sub.2 O.sub.3 or Ga.sub.2 O.sub.3 5 to 11 ______________________________________where M is potassium or a mixture of potassium and one or more other alkali metals.

Abstract: Zeolite L with cylindrical morphology and having excellent properties as a catalyst base may be prepared with high crystallinity and reduced contamination even in large scale syntheses were fluctuation in gel compositions may occur by employing a gel composition having the following molar ratios of components:2.64-2.67 M.sub.2/n O:Al.sub.2 O.sub.3 :8.8-9.7 SiO.sub.2 :145-160 H.sub.2 Owhere M is a cation of valence n, especially potassium. The ratio M.sub.2/n O:SiO.sub.2 is preferably at least 0.275.

Abstract: Hydrocarbon conversion processes which use catalyst compositions comprising a core of silica with an overlying modified-silica zeolite, preferably containing aluminium, gallium or boron, show improved catalytic activity. The composites are prepared by introducing preformed silica particles, preferably with a crystallite size greater than 0.1.mu., into a reaction mixture comprising a silicon source, a source of the modifying element, and preferably an organic template such as a tetraalkylammonium compound to form the modified-silica zeolite with a constraint index of from 1 to 12. The weight ratio of the silica core to SiO.sub.2 in the reaction mixture is preferably 1:1 to 10:1.

Abstract: Reduced downgrading in xylene isomerization of ethylbenzene-depleted feeds is achieved by carrying the process out over gallosilicate or borosilicate zeolites, preferably in the form of compositions comprising a core of catalytically-inactive crystalline silica with an overlying zeolite layer. The composites are prepared by introducing preformed silica particles, preferably with a crystallite size greater than 0.1.mu., into a reaction mixture comprising a silicon source, a source of the modifying element, and preferably an organic template such as a tetraalkylammonium compound. The weight ratio of the silica core to SiO.sub.2 in the reaction mixture is preferably 0.5:1 to 25:1.

Abstract: Catalyst compositions comprising a core of silica with an overlying modified-silica zeolite, preferably containing aluminium, gallium or boron, show improved catalytic activity. The composites are prepared by introducing preformed silica particles, preferably with a crystallite size greater than 0.1 .mu., into a reaction mixture comprising a silicon source, a source of the modifying element, and preferably an organic template such as a tetraalkylammonium compound to form the modified-silica zeolite with a constraint index of from 1 to 12. The weight ratio of the silica core to SiO.sub.2 in the reaction mixture is preferably 1:1 to 10:1.