Abstract: The specification describes a method and a fixed bed apparatus for producing olefinic hydrocarbons from a charge of saturated aliphatic hydrocarbons with 2 to 20 carbon atoms and hydrogen in a chamber 1 comprising a plurality of parallel tubes 3 filled with a catalyst and arranged in rows. A so-called reaction phase and a catalyst-regenerating phase are carried out in the tubes of the chamber. The tubes are heated by appropriate radiant heating means 6, arranged in layers substantially perpendicular to the tubes. These layers heat a first part of the tubes (at the feed side) with a heat flux greater than the mean heat flux of the chamber and a second, subsequent part with a mean flux no more than equal to the mean heat flux, so that the isothermicity of the catalyst is substantially maintained, using appropriate control means.

Abstract: In a process for the separation of p-xylene from a feed to be treated containing a mixture of xylenes and olefinic impurities, at least a portion of the feed is circulated in an enrichment zone (14) to enrich a first fraction (15) in p-xylene and provide a second fraction (18) which is depleted in p-xylene. The second fraction is circulated in an isomerisation zone (19) and an isomerate (20) is recovered which is recycled to the enrichment zone. At least a portion of the feed to be treated, the isomerate, or a mixture thereof is circulated in at least one selective hydrogenation zone (3) to partially remove the olefinic impurities and thereafter in at least one clay tretment zone (8) to remove additional olefinic impurities. An effluent is recovered which is sent to the enrichment zone.

Abstract: A process for the regeneration of a sulfur containing catalysts, wherein the catalyst is stripped of sulfur before the oxychlorination treatment of the regeneration process, typically before the catalyst is sent to the regeneration zone. The process is particularly useful for catalyst employed in hydrocarbon conversions such as dehydrogenation reactions, particularly those which comprise the injection of sulfur and/or at least one sulfur compound before or simultaneously to the introduction of the charge into the first reaction zone.

Abstract: A process is described for the high-efficiency selective hydrogenation of an aromatic hydrocarbon cut which also contains monoolefinic hydrocarbons and polyolefinic and/or acetylenic hydrocarbons with a bromine number of 10000 to 100 mg per 100 g of product with an aromatic degree of conversion which is limited to a maximum of 0.15% by weight, the process being characterized in that the cut, which is at least partially in the liquid phase, is passed with hydrogen into a hydrogenation zone in contact with a catalyst containing 0.1% to 1% by weight (with respect to the support) of palladium, the catalyst having been treated before activation with at least one organic sulphur-containing compound to introduce 0.05% to 1% of sulphur (by weight with respect to the weight of the catalyst), the process being carried out at a temperature in the range 20.degree. C. to 25.degree. C., at a pressure of 4-50 bar, a GHSV of 0.2-25 h.sup.-1 and with a H.sub.2 /monoolefin +polyolefin and/or acetylenes ratio in the range 0.

Abstract: A process for the selective hydrogenation of a fraction of hydrocarbons containing 2 to 20 carbon atoms and comprising monounsaturated olefinic hydrocarbons and/or aromatic compounds and at least one polyunsaturated hydrocarbon from the group formed by acetylenic compounds and dienes, in which the hydrocarbon fraction, which is at least partially in the liquid phase, circulates with hydrogen in a given direction in a reactor containing at least one fixed bed of a hydrogenation catalyst in the form of a divided solid, characterized in that said reactor is provided with at least one inlet conduit for a fluid mixture comprising said hydrocarbon fraction and hydrogen and at least one outlet conduit for the hydrogenated hydrocarbon fraction, and in that it comprises at least one static mixer upstream of said outlet for the hydrogenated hydrocarbon fraction.

Abstract: Process for the dehydrogenation of a charge incorporating saturated aliphatic hydrocarbons essentially having 3 to 5 carbon atoms per molecule, in which the charge, previously heated to the reaction temperature and without premixing with the hydrogen, is introduced at the inlet of at least one reactor, where the dehydrogenation reaction is performed in the presence of a catalyst, preferably incorporating a support having at least one oxide of an element chosen from among the groups IIA, IIB, IIIA, IIIB, IVA and IVB of the periodic classification of elements, at least one noble metal from the platinum family, at least one promotor metal and at least one alkali metal or alkaline earth metal.

Abstract: A continuous process for the dehydrogenation of paraffinic and olefinic hydrocarbons in the presence of a catalyst comprises circulating a charge containing said paraffinic hydrocarbons through at least two reactions zones of the moving bed type which are arranged in series, the catalyst flowing successively in each reaction zone. The catalyst which is drawn off from the last reaction zone is sent to a regeneration zone at the exit from which it is reintroduced close to the first reaction zone. The process comprises the injection of sulphur and/or at least one sulphur compound before or simultaneously to the introduction of the charge into the first reaction zone. In accordance with the process, the catalyst which is drawn off from the last reaction zone is sent into a stripping zone wherein the sulphur which it contains is removed before the catalyst is sent to the regeneration zone.

Abstract: The invention relates to a method of eliminating mercury or arsenic from a fluid in the presence of a solid mass for the recovery of mercury and/or arsenic. The said mass contains copper and sulphur at least partly in the form of copper sulphide and results (a) from the incorporation of a copper compound other than a sulphide into a solid mineral support, (b) possible calcination of the product obtained in stage (a), and from bringing the product obtained previously into contact with elementary sulphur and (d) a heat treatment.

Abstract: The invention concerns a catalytic composition resulting from placing at least one divalent nickel compound into contact with at least one hydrocarbylaluminum halide and at least one epoxy compound, in any order. It also concerns the use of the catalytic composition in a process of oligomerizing monoolefins.

Abstract: The invention concerns a catalytic composition resulting from placing at least one divalent nickel compound into contact with at least one hydrocarbylaluminum halide and at least one epoxy compound, in any order. It also concerns the use of the catalytic composition in a process of oligomerizing monoolefins.

Abstract: A catalyst is formed by reacting, in a hydrocarbon medium, a trialkylaluminum with a mixture of an alkyl titanate with an ether. The activity and the selectivity are improved when adding the trialkylaluminum to a pre-formed mixture of alkyl titanate with ether.

Abstract: Process for synthesizing 1-butene by dimerization of ethylene, in the presence of a catalyst formed by reacting, in a hydrocarbon medium, a trialkylaluminum with a mixture of an alkyl titanate with an ether. The activity and the selectivity are improved when adding the ether to a pre-formed mixture of alkyl titanate with trialkylaluminum.

Abstract: A process for oligomerizing olefins uses a catalyst composition obtained by contacting (a) bivalent nickel compound with (b) a hydrocarbylaluminum compound of the formula Al R.sub.x X.sub.y where R is a monovalent hydrocarbon radical, X is halogen, x is from 1 to 1.5, y is from 1.5 to 2, x+y being equal to 3, and (c) a Bronsted acid consisting preferably of a halogenocarboxylic acid of the formula R.sub.1 COOH in which R.sub.1 is a halogenoalkyl radical of the formula C.sub.m H.sub.p X.sub.q X being halogen, m an integer from 1 to 3, p being zero or an integer and q being an integer, the condition p+q=2m+1 being fulfilled. A preferred Bronsted acid is of the formula R.sub.2 COOH in which R.sub.2 is a halogenomethyl group of the formula CX.sub.n H.sub.3-n, X being halogen and n an integer from 1 to 3.

Abstract: An improved catalyst composition is obtained by contacting at least one bivalent nickel compound with at least one hydrocarbyl aluminum halide, at least one Bronsted organic acid and at least one anhydride of a carboxylic acid. The composition can be used as a catalyst for olefin oligomerization.

Abstract: A C.sub.2 or C.sub.3 hydrocarbon fraction comprising at least one mono-olefinic hydrocarbon and at least one acetylenic hydrocarbon, and optionally at least one diolefinic hydrocarbon, is hydrogenated selectively in contact with a palladium-on-alumina catalyst subjected to calcining at a relatively high temperature and whose palladium crystallites have an average size of at least 50 Angstroms.

Abstract: At least one of propene and butene is oligomerized, preferably dimerized, in an elongate cylindrical reaction zone. A recycle flow and the fresh feed charge are injected tangentially into said reaction zone. The catalyst preferably comprises a nickel compound and a hydrocarbyl aluminum halide.

Abstract: Catalyst composition for oligomerizing olefins, obtained by contacting (a) a bivalent nickel compound with (b) a hydrocarbylaluminum compound of the formula AIRCl.sub.2 where R is a monovalent hydrocarbon radical, and (c) a Bronsted acid consisting preferably of a halogenocarboxylic acid of the formula R.sub.1 COOH in which R.sub.1 is a halogenoalkyl radical of the formula C.sub.m H.sub.p X.sub.q, X being halogen, m an integer from 1 to 3, p being zero or an integer and q being an integer, the condition p+q=2m+1 being fulfilled. A preferred Bronsted acid is of the formula R.sub.2 COOH in which R.sub.2 is a halogenomethyl group of the formula CX.sub.n H.sub.3-n, X being halogen and n an integer from 1 to 3.