Abstract: A process for preparing porous crystalline alumino-silicates consisting of bringing into contact, in an aqueous environment, sodium silicate with an aluminum derivative at a molar SiO.sub.2 /Al.sub.2 O.sub.3 ratio greater than or equal to 8, in the presence of one or more alkaline hydroxides at a molar Me.sup.+ /SiO.sub.2 ratio greater than 0.6, where Me.sup.+ represents the alkaline metal or metals, and in the presence of a mineralizing agent, operating at a temperature of between 20.degree. and 100.degree. C., and controlling the molar OH.sup.- /SiO.sub.2 ratio of the resultant mixture at a value of 0.01 and 0.8, the resultant mixture being crystallized at said molar OH.sup.- /SiO.sub.2 ratio in a closed environment for a period of between some hours and 40 days at a temperature of between 100.degree. and 200.degree. C.

Abstract: The invention provides a silica-based crystalline material that incorporates titanium into the crystal lattice. A process for preparing this material is also disclosed which is based on the reaction of silica, tetra-alkyl orthotitante and tetrapropyl-ammonium hydroxide.

Abstract: The invention is concerned with particular crystalline silica materials that contain boron in the crystal lattice. These materials are useful as catalysts for many reactions.

Abstract: In the process for dehydrating an aliphatic alcohol to convert same into the corresponding ether, the improvement consisting in that the catalyst is an active alumina on the surface of which a layer of a silicon compound has been deposited. Long life of the catalyst and improved conversion rates are the main advantages.

Abstract: In the reaction of conversion of nitriles to amides, more particularly, but not exclusively, acrylonitrile to acrylamide, the improvement consisting in the adoption, as a catalyst, of a copper-based catalyst which is prepared by reacting an organic copper chelate with aluminum-alkyl and/or an aluminum hydride. Higher yields and higher selectivity are obtained over the usual copper-based catalysts.

Abstract: A process is disclosed for preparing tertiary olefins having a high degree of purity and in good yields starting from tertiary ethers such as methyltert.butyl ether and in which the improvement comprises using an extremely efficient catalyst system which consists of a crystalline silica having a high specific surface area and which has been modified by an oxide of a metallic cation having an at least partially amphoteric character. Such catalyst may be, if appropriate, accompanied by an alumina-modified silica as an adjuvant co-catalyst.

Abstract: A method for the production of dimethyl ether by catalytical reaction between carbon monoxide and hydrogen is disclosed, in which an improved catalyst system is used. The improved catalyst is composed of a mixture of oxides and/or salts of metals such as Al, Cr, La, Mn, Cu, Zn and their mixtures which have been subjected to a stabilization process with a compound of silicon having substituents of various natures; such as hydrocarbonaceous radicals, and halogens. This catalyst is a considerable advance over the prior art.

Abstract: The invention relates to the skeleton isomerization of alkenes and, more particularly, to the catalyst for the isomerization reaction, the catalyst being prepared by treating an oxide of a metal of the group comprising aluminium, titanium, magnesium, silicon, chrome, zirconium, iron and their mixtures, preferably an active alumina, with a silicon compound, preferably an alkyl ester of the orthosilicic acid, and then subjecting the thus treated oxide to drying and to a controlled oxidation. Thus catalyst is obtained which permits higher yields and selectivity of the isomerization reaction to be achieved, as well as a longer operative life of the catalyst before the regeneration thereof.