Abstract: A method for converting a polymer or oligomer derived from an ethylenically unsaturated monomer into alkanes or into a hydrocarbon fraction or a lower oligomer fraction by controlled hydrocracking, wherein the polymer or oligomer is exposed to a catalyst based on a metal hydride or an organometallic complex supported on a mineral carrier, the complex having at least one hydrocarbon ligand and optionally at least one hydride ligand, and the resulting mixture is reacted with hydrogen to cause catalytic hydrocracking of the polymer or oligomer. The polymer or oligomer is broken down into reclaimable products with a lower molecular weight for use, e.g., in the field of polymers, particularly controlled molecular weight polymers, fuels or lubricants.

Abstract: A process for the preparation of organic compounds or polymers containing one or more sulphur atoms and including one or more double bonds in a hydrocarbon chain is described. An acyclic sulphur-containing olefin or an unsaturated sulphur-containing cyclic hydrocarbon undergoes a self metathesis reaction or a cross metathesis reaction with a non-sulphur-containing acyclic olefin or a non-sulphur-containing unsaturated cyclic hydrocarbon to produce novel olefins, novel dienes, and/or olefinic polymers containing one or more sulphur atoms.

Abstract: The invention relates to an alumino-silicate type catalyst containing an omega zeolite with a Si/Al atomic ratio of between 2.5 and 100, with a content by weight of sodium of less than 2000 ppm (in relation to the weight of dry zeolite) and further containing, at least one metal selected from group IIa, IIb, and IVa metals, and at least one group VIII metal.The catalyst is prepared by the grafting of an organometallic compound of said group IIa, IVb, IIb, IVa metals.The catalyst is particularly suitable for the isomerization of an aromatic C.sub.8 cut.

Abstract: The invention concerns a process for the selective hydrogenation of polyunsaturated cyclic compounds comprising at least one endocyclic carbon-carbon double bond and at least one terminal exocyclic carbon-carbon double bond, said double bonds not being conjugated, to form a mixture essentially containing the saturated ring compound and comprising at least one terminal exocyclic double bond, the process being carried out in the presence of hydrogen under a pressure of from 1 to 10 MPa and at a temperature of from 0.degree. to 200.degree. C., and in the presence of a catalyst including a support and (a) from 0.1 to 5% by weight of at least one metal from group VIII (iridium, osmium, nickel, palladium, platinum and rhodium) and (b) from 0.01 to 15% by weight of at least one metal from group IVa (tin, germanium and lead), the molar ratio between metals of group VIII and group IVa being between 0.3 and 3. The process is used for the hydrogenation of 4-vinylcylcohexene to vinylcyclohexane.

Abstract: The invention relates to an alumino-silicate type catalyst containing an omega zeolite with a Si/Al atomic ratio of between 2.5 and 100, with a content by weight of sodium of less than 2 000 ppm (in relation to the weight off dry zeolite) and further containing, at least one metal selected from group IIa, IIb, and IVa metals, and at least one group VIII metal.The catalyst is prepared by the grafting of an organometallic compound of said group IIa, IVb, IIb, IVa metals.The catalyst is particularly suitable for the isomerization of an aromatic C.sub.8 cut.

Abstract: For the at least partial separation of aliphatic paraffins into at least one effluent comprising the least branched paraffins and at least one effluent comprising the most branched paraffins, use is made of at least one adsorbent bed comprising at least one grafted microporous solid. A preferred use of the invention relates to the treatment of a charge obtained from an isomerization zone, whereby at least one adsorbent bed makes it possible to separate the charge into a first effluent comprising the normal paraffins and a second effluent, and at least one adsorbent bed on which passes the second effluent, comprising at least one grafted microporous solid, making it possible to obtain a third effluent comprising the monomethyl branched paraffins and a fourth effluent comprising the polymethyl branched paraffins.

Abstract: The invention concerns the production of a substituted or unsubstituted aniline by selective hydrogenation of the corresponding nitroaromatic compound. It is characterized by the use of a catalyst based on a metal selected from rhodium and ruthenium and based on a metal selected from the group comprising tin, germanium and lead.

Abstract: Process of polymerization of unsaturated hydrocarbons, with an initial induction period, by means of a catalyst constituted by a halogeno-phenate of tungsten, of which the phenate group carries one or more substituents, in the presence of an organometallic co-catalyst; the halogeno-phenate is chosen from amongst those represented by the formula ##STR1## where X is a halogen, especially Cl or Br, n is a whole number 2, 3 or 4, R.sup.1 is H or a C.sub.1 to C.sub.8 straight- or branched-chain alkoxy group, R.sup.2 is H or a C.sub.3 to C.sub.9 branched-chain alkyl group, R.sup.1 and R.sup.2 never being hydrogen simultaneously.

Abstract: Process for the preparation of aromatic aldehydes by hydrocarbonylation of chloro- or bromoaromatic compounds. In the presence of an acceptor for an oxygen-free acid, a palladium/phosphine complex and, if appropriate, a phosphine, a mixture of carbon monoxide and hydrogen is reacted with chloro- or bromoarenetricarbonylchromiums.

Abstract: There is disclosed a process for the metathesis of olefins. The process utilizes as a catalyst an alumina carrier which is treated with a chlorination agent with the subsequent addition to tungsten compounds, molybdenum compounds or mixtures thereof to the chlorinated carrier.