Abstract: The invention relates to catalytic compositions for the hydrogenation of 1,1,2-trichloro-1,2,2-trifluoroethane to chlorotrifluoroethylene and trifluoroethylene comprising a porous oxygenated support impregnated with a metal of group VIII of the periodic table of the elements and one or more compounds chosen from the salts of an alkali or alkaline-earth metal.The invention also relates to a process for obtaining these catalytic compositions and a process of hydrogenation by means of these catalytic compositions.

Abstract: The invention relates to catalytic compositions for the hydrogenation of chlorofluoroalkenes to fluoroalkenes, comprising a porous carrier impregnated with a metal of group VIII of the Periodic Table of the elements and with one or more compounds chosen from the salts of an alkali metal or alkaline-earth metal.The invention also relates to a process for obtaining these catalytic compositions and a process of hydrogenation by means of these catalytic compositions.

Abstract: A method for activating supported chromium oxide catalysts in which a chromium-containing catalyst on a silica-containing base is first heated in an oxidizing atmosphere at temperatures up to about 850.degree. C. and then cooled down. During the cooling step of the catalyst, the oxidizing atmosphere is replaced by a non oxidizing one, leading to an activated catalyst.A process for the polymerization of alpha-olefins, especially ethylene, in which at least one alpha-olefin is contacted, under polymerization conditions, with the catalyst activated by the method described above.

Abstract: Process for the production of a composite of metal oxides, according to which a metal alcoholate is hydrolysed in the presence of metal (hydr)oxide particles in order to convert the metal alcoholate into a metal (hydr)oxide gel enveloping the metal (hydr)oxide particles. Powders of a composite of metal oxides obtained by this process and ceramic materials obtained by sintering a powder of this type.

Abstract: Process for the manufacture of a powder of mixed metal oxides by cohydrolysis of metal alcoholates in the presence of an acidic organic compound and mixed metal oxide powders in which the molar relationships R1 and R2 of a metal oxide to the sum of the metal oxides in the powder and in a particle of the powder are such that ##EQU1## The process applies especially well to powders of zirconia doped with yttrium oxide or other oxides.

Abstract: A method for activating supported chromium oxide catalysts in which a chromium-containing catalyst on a silica-containing base is first heated in an oxidizing atmosphere at temperatures up to about 850.degree. C. and then cooled down. During the cooling step of the catalyst, the oxidizing atmosphere is replaced by a non-oxidizing one, leading to an activated catalyst. A process for the polymerization of alpha-olefins, especially ethylene, in which at least one alpha-olefin is contacted, under polymerization conditions, with the catalyst activated by the method described above.

Abstract: The invention relates to catalytic compositions for the hydrogenation of chlorofluoroalkenes to fluoroalkenes, comprising a porous carrier impregnated with metal of group VIII of the Periodic Table of the elements and with one or more compounds chosen from the salts of an alkali metal or alkaline-earth metal.The invention also relates to a process for obtaining these catalytic compositions and a process of hydrogenation by means of these catalytic compositions.

Abstract: The invention relates to catalytic compositions for the hydrogenation of 1,1,2-trichloro-1,2,2-trifluoroethane to chlorotrifluoroethylene and trifluoroethylene comprising a porous oxygenated support impregnated with a metal of group VIII of the periodic table of the elements and one or more compounds chosen from the salts of an alkali or alkaline-earth metal.The invention also relates to a process for obtaining these catalytic compositions and a process of hydrogenation by means of these catalytic compositions.

Abstract: An amorphous powder of titanium oxide and of barium and/or strontium oxide is precipitated by the hydrolysis of titanium alcoholate in the presence of barium oxide, hydroxide or alcoholate or strontium oxide, hydroxide or alcoholate and an acid organic compound containing more than 6 carbon atoms, and the amorphous powder is heated while being treated with a stream of gas containing water vapour, ammonia or CO.sub.2, to crystallize the barium or strontium titanate and distill off the acid organic compound. The barium or strontium titanate crystals are less than one micron in size and have an irregular, angular morphology.

Abstract: Process for the manufacture of a mixed metal oxide powder, in which at least one metal alcoholate is hydrolyzed in the presence of at least one metal oxide or hydroxide and of an acidic organic compound containing more than 6 carbon atoms in the molecule. The process is applicable to the production of barium titanate powders.

Abstract: Process for the manufacture of a powder of mixed metal oxides by cohydrolysis of metal alcoholates in the presence of an acidic organic compound and mixed metal oxide powders in which the molar relationships R.sub.1 and R.sub.2 of a metal oxide to the sum of the metal oxides in the powder and in a particle of the powder are such that ##EQU1## The process applies to powders of zirconia doped with yttrium oxide.

Abstract: Process for the manufacture of vitreous metal oxides in which a metal alcoholate derived from an alcohol, the pka of which is less than 15.74, is hydrolysed with an aqueous medium, the pH of which is greater than 1.5. The process is applied especially to the manufacture of vitreous zirconium oxide.

Abstract: Process for the manufacture of a metal oxide powder for ceramic materials by the hydrolysis of a metal alcoholate in the presence of an acidic organic compound.The process applies to the production of metal oxide powders, such as zirconia powders, with a mean particle diameter of between 0.05 and 2 microns.

Abstract: A process for the manufacture of olefine oxides, comprising reacting, with an olefine, an organic solution of percarboxylic acid which is obtained by reacting the corresponding carboxylic acid with hydrogen peroxide. The organic solvent employed is a mixture of inert organic solvents which does not form an azeotrope with the olefine to be epoxidized or with the olefine oxide, and which contains a volatile solvent, the boiling point of which is lower than that of the olefine oxide, and a solvent of low volatility, the boiling point of which is higher than that of the olefine oxide.

Abstract: A continuous process for the manufacture of carboxylic peracids by reacting the corresponding carboxylic acid with hydrogen peroxide in the presence of a catalyst and in the presence of an inert organic liquid which is a solvent for the peracid and is capable of forming a heterogeneous azeotrope with water, removing the water present in the reaction mixture by distillation of the water/organic liquid azeotrope, and keeping sufficient water in the reaction mixture to allow the formation of an aqueous phase which is separate from an organic phase containing the organic liquid.

Abstract: A continuous process for the manufacture of carboxylic peracids by reacting the corresponding carboxylic acid with hydrogen peroxide in the presence of a catalyst and in the presence of an inert organic liquid which is a solvent for the peracid and is capable of forming a heterogeneous azeotrope with water, removing the water present in the reaction mixture by distillation of the water/organic liquid azeotrope, and keeping sufficient water in the reaction mixture to allow the formation of an aqueous phase which is separate from an organic phase containing the organic liquid.