Abstract: A process for preparing light olefins from corresponding paraffins consists of reacting said paraffins in a reactor, operating at a temperature of between 450 and 800° C., a pressure of between 0.1 and 3 atm absolute and a GHSV of between 100 and 10000 h?1, with a catalytic system containing gallium, platinum, possibly one or more alkaline or alkaline-earth metals, and a support consisting of alumina in delta or theta phase or in delta+theta or theta+alpha or delta+theta+alpha mixed phase, modified with silica, the gallium, expressed as Ga2O3, being in a quantity of between 0.1 and 33.6 wt %, the platinum being in a quantity of between 1 and 99 ppm, the alkaline or alkaline-earth metals, expressed as oxide, being in a quantity of between 0 and 5 wt %, and the silica being in a quantity of between 0.08 and 3 wt %, the rest to 100% being alumina, and regenerating said catalytic system in a regenerator by burning off the coke which has deposited on its surface, without subsequently reducing it.

Abstract: A process for preparing light olefins from corresponding paraffins consists of reacting said paraffins in a reactor, operating at a temperature of between 450 and 800° C., a pressure of between 0.1 and 3 atm absolute and a GHSV of between 100 and 10000 h−1, with a catalytic system containing gallium, platinum, possibly one or more alkaline or alkaline-earth metals, and a support consisting of alumina in delta or theta phase or in delta+theta or theta+alpha or delta+theta+alpha mixed phase, modified with silica, the gallium, expressed as Ga2O3, being in a quantity of between 0.1 and 33.6 wt %, the platinum being in a quantity of between 1 and 99 ppm, the alkaline or alkaline-earth metals, expressed as oxide, being in a quantity of between 0 and 5 wt %, and the silica being in a quantity of between 0.

Abstract: A process for obtaining light olefins by the dehydrogenation of corresponding paraffins, by reacting the paraffins with a catalytic system containing chromium oxide, tin oxide, at least one alkali metal oxide, and an alumina-silica carrier, and then regenerating the catalytic system in a regenerator by burning coke deposited on its surface at a temperature higher than the average temperature of the reactor.

Abstract: Catalytic system for dehydrogenating ethylbenzene to styrene, containing chromium oxide, tin oxide, at least one oxide of an alkaline metal (M) and an alumina carrier, in delta or theta phase or in a mixture of delta+theta or theta+alpha or delta+theta+alpha phases, modified with silica, and characterized in that: the chromium, expressed as Cr2O3, is in a quantity of between 6 and 30% by weight; the tin, expressed as SnO, is in a quantity of between 0.1 and 3.5% by weight; the alkaline metal, expressed as M2O, is in a quantity of between 0.4 and 3% by weight; the silica is in a quantity of between 0.08 and 3% by weight, the complement to 100 being alumina.

Abstract: Process for the production of styrene which comprises:a) feeding to an alkylation unit a stream of benzene and a stream of recycled product containing ethylene;b) mixing the stream at the outlet of the alkylation unit, containing ethylbenzene, with a stream consisting of ethane;c) feeding the mixture thus obtained to a dehydrogenation unit containing a catalyst capable of contemporaneously dehydrogenating ethane and ethylbenzene;d) feeding the product leaving the dehydrogenation unit to a separation section to produce a stream essentially consisting of styrene and a stream containing ethylene;e) recycling the stream containing ethylene to the alkylation unit.

Abstract: Catalytic system for dehydrogenating ethylbenzene to styrene, containing chromium oxide, tin oxide, at least one oxide of an alkaline metal (M) and an alumina carrier, in delta or theta phase or in a mixture of delta+theta or theta+alpha or delta+theta+alpha phases, modified with silica, and characterized in that:the chromium, expressed as Cr.sub.2 O.sub.3, is in a quantity of between 6 and 30% by weight;the tin, expressed as SnO, is in a quantity of between 0.1 and 3.5% by weight;the alkaline metal, expressed as M.sub.2 O, is in a quantity of between 0.4 and 3% by weight,the silica is in a quantity of between 0.08 and 3% by weight, the complement to 100 being alumina.

Abstract: Zeolites having a pore diameter comprised within the range of from 5 to 12 .ANG. are bonded with amorphous oligomeric silica, by dispersing them in an aqueous solution of silica and alkylammonium hydroxide, and submitting the obtained suspension to a quick drying.

Abstract: The process for activating a catalytic composition for paraffin dehydrogenation containing gallium, alumina, possibly silica and/or one or more alkaline or alkaline-earth metals, comprises thermal activation in air followed by post-activation effected by the following stages:oxidation with air and/or oxygen or a mixture containing oxygen and inert gas;purging with inert gas;reduction with hydrogen or a mixture of hydrogen and an inert or reducing gas.The catalytic composition activated by said process contains gallium, alumina, silica and possibly one or more alkaline or alkaline-earth metals, the alumina being in .delta. or .theta. phase or in .delta.+.theta. or .delta.+.theta.+.alpha. phase mixture.

Abstract: The process for activating a catalytic composition for paraffin dehydrogenation containing gallium, alumina, possibly silica and/or one or more alkaline or alkaline-earth metals, comprises thermal activation in air followed by post-activation effected by the following stages:oxidation with air and/or oxygen or a mixture containing oxygen and inert gas;purging with inert gas;reduction with hydrogen or a mixture of hydrogen and an inert or reducing gas.The catalytic composition activated by said process contains gallium, alumina, silica and possibly one or more alkaline or alkaline-earth metals, the alumina being in .delta. or .theta. phase or in .delta.+.theta. or .delta.+.theta.+.alpha. phase mixture.

Abstract: A crystalline, porous, synthetic material is disclosed, together with its related preparation process.Such a material of zeolitic character, containing silicon, titanium and iron oxides, corresponds, in its calcined and anhydrous state, to the following empi rical formulapHFeO.sub.2.qTiO.sub.2.SiO.sub.2wherein p has a value greater than zero and lower than or equal to 0.050, q has a value greater than zero and lower than or equal to 0.025, and the H.sup.+ of HFeO.sub.2 can be at least partly replaceable or replaced by cations.

Abstract: A crystalline, porous, synthetic material is disclosed, together with its related preparation process.Such a material of zeolitic character, containing silicon, titanium and aluminum oxides, corresponds, in its calcined and anhydrous state, to the following empirical formula:p HAlO.sub.2.q TiO.sub.2.SiO.sub.2wherein p has a value greater than zero and lower than or equal to 0.050, q has a value greater than zero and lower than or equal to 0.025, and the H.sup.+ of HAlO.sub.2 can be at least partly replaceable or replaced by cations.

Abstract: A catalytic composition for the dehydrogenation of C.sub.2 -C.sub.5 paraffins, constituted by:platinum, in an amount comprised within the range of from 0.01 to 3% by weight,optionally tin, in an amount comprised within the range of from 0 to 1.5% by weight,a support selected from:titanated alumina,titanated silica and/ortitanium silicalitein which the titanium amount in the same support is comprised within the range of from 0.05 to 3% by weightis disclosed.

Abstract: The invention discloses a catalyst on the basis of silicon and titanium having the form of microspheres and constituted by oligomeric silica and by titanium-silica-lite crystals having an oligomeric silica/titanium-silicalite molar ratio comprised within the range of from 0.05 to 0.11, wherein the crystals of titanium-silicalite are encaged by means of Si-O-Si bridges.

Abstract: The invention discloses a catalyst on the basis of silicon and titanium having the form of microspheres and constituted by oligomeric silica and by titanium-silicalite crystals having an oligomeric silica/titanium-silicalite molar ratio comprised within the range of from 0.05 to 0.11, wherein the crystals of titanium-silicalite are encaged by means of Si--O--Si bridges.

Abstract: The present invention relates to a catalyst for the selective decomposition of cumene hydroperoxide, composed of zeolite crystals wherein a portion of the silicon atoms in the crystal lattice of silica is replaced by Al and B. The zeolite crystals are bonded to each other by a siliceous bonding agent which allows the catalyst to assume the shape of mechanically stable microspheres.The invention relates also to a process in which the catalyst is used, and to the related operating conditions.

Abstract: A process for the epoxidation of olefinic compounds, consisting of reacting said compounds with hydrogen peroxide either introduced as such or produced by substances capable of generating it under the reaction conditions, in the presence of synthetic zeolites containing titanium atoms, of general formula:xTiO.sub.2.(1-x)SiO.sub.2,where x lies between 0.0001 and 0.04, and possibly in the presence of one or more solvents, operating at a temperature of between 0.degree. and 150.degree. C., and at a pressure of between 1 and 100 ata.

Abstract: The invention relates to a method for the preparation of a catalyst for the dehydrogenation of C.sub.3 -C.sub.5 paraffins consisting in impregnating calcined aluminum oxide with a solution of chromium and potassium compounds, in drying and then impregnating the product obtained with a solution of a compound of silicon, the catalyst obtained being finally dried and calcined.

Abstract: The present invention relates to a catalyst for the selective decomposition of cumene hydroperoxide, composed of zeolite crystals wherein a portion of the silicon atoms in the crystal lattice of silica is replaced by Al and B. The zeolite crystals are bonded to each other by a siliceous bonding agent which allows the catalyst to assume the shape of mechanically stable microspheres.The invention relates also to a process in which the catalyst is used, and to the related operating conditions.

Abstract: The invention discloses a catalyst on the basis of silicon and titanium having the form of microspheres and constituted by oligomeric silica and by titanium-silicalite crystals having an oligomeric silica/titanium-silicalite molar ratio comprised within the range of from 0.05 to 0.11, wherein the crystals of titanium-silicalite are encaged by means of Si-O-Si bridges.

Abstract: A process for oxidizing vinylbenzene compounds, consisting of reacting said compounds with an aqueous solution of hydrogen peroxide in the presence of synthetic zeolites containing titanium atoms, of general formula:xTiO.sub.2.(1-x)SiO.sub.2where x lies between 0.0001 and 0.04, and possibly in the presence of one or more solvents, operating at a temperature of between 20.degree. and 150.degree. C.