The present invention concerns a catalyst and pre-treatment process for acidic charges consisting of sulfated zirconia and cerium for the production of biofuels, characterized in that the catalyst has greater activity and resistance to deactivation with acidic charges.

The invention relates to a catalyst comprising a support based on alumina or silica or silica-alumina, at least one group VIII element, at least one group VIB element and at least one organic compound of formula (I) ##STR00001##
in which R.sub.1 is a hydrocarbon-based radical comprising from 1 to 12 carbon atoms, R.sub.2 and R.sub.3 are chosen from a hydrogen atom and a hydrocarbon-based radical comprising from 1 to 12 carbon atoms, X is chosen from an oxygen atom or a sulfur atom except when R.sub.2 and R.sub.3 represent a hydrogen atom, in which case X is an oxygen atom, Y is chosen from a hydrogen atom, a hydrocarbon-based radical comprising from 1 to 12 carbon atoms or a unit —C(O)R.sub.4, R.sub.4 being chosen from a hydrogen atom and a hydrocarbon-based radical comprising from 1 to 12 carbon atoms.

The invention relates to a catalyst comprising a support based on alumina or silica or silica-alumina, at least one group VIII element, at least one group VIB element and at least one organic compound of formula (I) ##STR00001##
in which R.sub.1 is a hydrocarbon-based radical comprising from 1 to 12 carbon atoms, R.sub.2 and R.sub.3 are chosen from a hydrogen atom and a hydrocarbon-based radical comprising from 1 to 12 carbon atoms, X is chosen from an oxygen atom or a sulfur atom except when R.sub.2 and R.sub.3 represent a hydrogen atom, in which case X is an oxygen atom, Y is chosen from a hydrogen atom, a hydrocarbon-based radical comprising from 1 to 12 carbon atoms or a unit —C(O)R.sub.4, R.sub.4 being chosen from a hydrogen atom and a hydrocarbon-based radical comprising from 1 to 12 carbon atoms.

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

The problem to be solved by the present invention is to provide a good NOx selective reduction catalyst. To solve the problem is a NOx selective reduction catalyst containing a composite oxide of Ti, Ce, W, and P or S.

The problem to be solved by the present invention is to provide a good NOx selective reduction catalyst. To solve the problem is a NOx selective reduction catalyst containing a composite oxide of Ti, Ce, W, and P or S.

The present invention relates to heterogeneous acid catalysts comprising or consisting of mixed metal salts, of lithium and aluminum phosphates and sulfates, and combinations with metallic cations, such as magnesium, titanium, zinc, zirconium and gallium, to provide adequate Lewis acidity; organic or inorganic porosity promoters, such as polysaccharides; and agglomerates, such as clays, kaolin and metal oxides of the type M.sub.xO.sub.y, where; M=Al, Mg, Sr, Zr or Ti, and other metals of groups IA, IIA and IVB, x=1 or 2 and y=2 or 3, for the formation of particles. A process is disclosed for obtaining from the catalyst by the hydrolysis of aluminum lithium hydride with water and oxygenated solvent, such as an ether. The catalysts are used in batch reactor and continuous flow systems in reactions that require moderate Lewis acidity, such as refining, petrochemical and general chemistry, including the transesterification of glycerides to produce alkyl esters.