Abstract: A process for oligomerizing propylene is described, consisting of reacting said olefin in the presence of an X-ray amorphous alumina-silica gel catalyst with a silica/alumina molar ratio of between 30/1 and 500/1, a surface area of between 500 and 1000 m.sup.2 /g, a total pore volume of between 0.3 and 0.6 ml/g, an average pore diameter of the order of 10 .ANG. or less, and free or substantially free of pores with a diameter greater than 30 .ANG..

Abstract: Regeneration of an ammoxidation catalyst which is exhausted as a result of prolonged exposure to ammoxidation conditions, containing oxides of Mo, Bi, P, Fe, Co, Ni and possibly an alkali metal, particularly K, on a granular support, particularly silica, by means of a method including:the impregnation of the granules of spent catalyst with an aqueous molybdic acid solution, or with an aqueous solution of partially or totally salified molybdic acid in the form of the ammonium salt, with a volume of impregnation solution less than the total pore volume of the catalyst subjected to regeneration;the drying of the impregnated granules at a temperature of from 100.degree. to 200.degree. C.;the calcining of the dried granules at a temperature of from 250.degree. to 450.degree. C., solely when the impregnation is with an aqueous solution of partially or totally salified molybdic acid.

Abstract: A process is described for the preparation of catalysts based on molybdenum and iron oxides which comprises their controlled precipitation in an aqueous medium from sodium molybdate and a soluble ferric salt, the separation and the washing of the precipitate until its sodium content is reduced to less than 150 ppm. According to one embodiment, the sodium molybdate used as the reagent results from the action of aqueous sodium hydroxide on the spent catalyst.

Abstract: Recovery of molybdenum from a solid mixture, such as an exhausted catalyst, containing molybdenum in the oxide form or in the form of molybdic ions and other metallic compounds.The mixture is contacted with an aqueous alkali metal hydroxide to solubilize molybdenum in the form of an alkali metal molybdate, and after filtration the aqueous solution of alkali metal molybdate thus obtained is contacted with a strong cationic exchange resin to convert said molybdate into molybdic acid.

Abstract: An oxychlorination catalyst precursor is described which is constituted by porous microspheroidal alumina particles impregnated with 3 to 7% by weight of cupric chloride (expressed in terms of the copper metal) and containing from 0.5 to 2% by weight of water, in which the copper is uniformly distributed over the entire surface area of the particles with a degree of non-uniformity not greater than .+-.7%.A process for the preparation of such a catalyst precursor is also described.The precursor is activated to give a catalyst which is readily fluidizable and which enables the oxychlorination of ethylene to dichloroethane to be carried out with high activity and selectivity values.

Abstract: Preparation of a catalyst based on molybdenum and iron oxides by precipitation from a soluble molybdenum compound and a soluble ferric salt, with separation of the precipitate from its mother waters and washing with deionized water.Molybdic ions are recovered from the mother waters and washing waters by contacting the latter with a salified anionic exchange resin, which is then contacted with aqueous alkali metal hydroxide to yield an aqueous solution of alkali metal molybdate.The molybdenum thus recovered may be recycled to the precipitation step upon conversion of the molybdate into molybdic acid by treatment with a strong cationic exchange resin, and possible conversion of the acid into ammonium paramolybdate.

Abstract: Chlorobenzene is produced by contacting a gaseous flow comprising benzene, oxygen and a halogenating agent, at a temperature of from 190.degree. to 230.degree. C., with a fluidized bed of catalyst particles comprising copper chloride deposited on an eta alumina support having a total volume of pores of from 0.3 to 0.5 ml/g and a surface area of from 250 to 400 m.sup.2 /g.