Abstract: Catalytic process for the partial conversion of a gaseous mixture containing carbon monoxide and hydrogen into a mixture of hydrocarbons, including bringing the said gaseous mixture into contact with a solid catalyst, the solid catalyst having a porous support with a composite material including SiC and a titanium carbide and/or a titanium oxide, and an active phase. The support is prepared in the form of grains, beads, or extrudates, or in the form of cylinders or sheets of cellular foam.

Abstract: Catalysts supports and catalysts capable of being used in heterogeneous catalysis. The catalyst support belongs to the porous supports based on silicon carbide (SiC), in particular, based on ?-SiC, modified by a surface deposit of TiO2.

Abstract: Catalysts supports and catalysts capable of being used in heterogeneous catalysis. The catalyst support belongs to the porous supports based on silicon carbide (SiC), in particular, based on ?-SiC, modified by a surface deposit of TiO2.

Abstract: Catalytic process for the partial conversion of a gaseous mixture containing carbon monoxide and hydrogen into a mixture of hydrocarbons, including bringing the said gaseous mixture into contact with a solid catalyst, the solid catalyst having a porous support with a composite material including SiC and a titanium carbide and/or a titanium oxide, and an active phase. The support is prepared in the form of grains, beads, or extrudates, or in the form of cylinders or sheets of cellular foam.

Abstract: The invention relates to a method of producing a composite comprising nanofibres or nanotubes on a porous ?-SiC substrate, said method comprising the following steps: (a) a catalyst for growing nanotubes or nanofibres is incorporated into said porous ?-SiC substrate or into an SiC precursor; (b) carbon nanotubes or nanofibres are grown from a mixture comprising hydrogen and at least one hydrocarbon; and (c) optionally, said carbon nanotubes or nanofibres are converted to SiC nanofibres. This composite may be used as a catalyst or catalyst support.

Abstract: This invention relates to ?-SiC foam parts with a specific surface area preferably equal to at least 5 m2/g and with at least two zones A and B with a different cellular porosity distribution, wherein the parts were made by chemical transformation of a porous precursor medium comprising at least two blocks A? and B?, each having a different cellular porosity distribution, and in that the at least two zones A and B are derived from the chemical transformation of the two blocks A? and B?. This foam, optionally after deposition of an active layer, may be used as a filter medium in cartridges designed for the purification of exhaust gases. The invention also relates to manufacturing processes for preparing such a filter medium.

Abstract: The photocatalyst based on a composite WO3—SiC/TiO2 semiconductor and subjected to radiation whose wavelength is at least partly less than 400 nm gives1 photocatalytic oxidation of volatile organic compounds and leads to their total mineralisation into CO2 and H2O. The process for the photocatalytic purification of industrial, agricultural or domestic gaseous effluent may be conducted at room pressure and temperature. Its conversion rate is high and stable.

Abstract: The invention relates to a method for producing a composite material based on ?-SiC, said method comprising the following steps: (a) a precursor mixture is prepared, said mixture comprising at least one ?-SiC precursor with at least one, preferably thermosetting, carbonated resin, (b) the precursor mixture is fabricated, especially in the form of granulated material, plates, tubes or bricks, in order to form an intermediate part; (c) the resin is polymerised; (d) said intermediate parts are introduced into a receptacle; (e) said receptacle is closed by a closing means in such a way that an over-pressure can escape; and (f) the intermediate parts are thermally treated at a temperature of between 1100 and 1500° C. in order to eliminate the organic constituents of the resin and to form ?-SiC in the final part.

Abstract: A SiC-based composite material capable of use as an inner coating for an aluminium smelting furnace or as an inner coating for a fused salt electrolytic cell, wherein said composite material has been prepared from a precursor mixture comprising at least one ?-SiC precursor and at least one carbonated resin, and wherein said composite material contains inclusions, and wherein at least one part thereof comprises ?-SiC, in a ?-SiC matrix.

Abstract: The photocatalyst based on a composite WO3—SiC/TiO2 semiconductor and subjected to radiation whose wavelength is at least partly less than 400 nm gives photocatalytic oxidation of volatile organic compounds and leads to their total mineralisation into CO2 and H2O. The process for the photocatalytic purification of industrial, agricultural or domestic gaseous effluent may be conducted at room pressure and temperature. Its conversion rate is high and stable.

Abstract: This invention relates to ?-SiC foam parts with a specific surface area preferably equal to at least 5 m2/g and with at least two zones A and B with a different cellular porosity distribution, wherein the parts were made by chemical transformation of a porous precursor medium comprising at least two blocks A? and B?, each having a different cellular porosity distribution, and in that the at least two zones A and B are derived from the chemical transformation of the two blocks A? and B?. This foam, optionally after deposition of an active layer, may be used as a filter medium in cartridges designed for the purification of exhaust gases. The invention also relates to manufacturing processes for preparing such a filter medium.

Abstract: An improved method for the selective vapor phase oxidation of propylene to acrolein in a recirculating solids reactor system using a bismuth molybdate multimetal oxide involving specific reactant concentrations (preferably 5 mol % to 30 mol % propylene, 0 to 20 mol % oxygen, and the remainder inert gas), particle size (1 to 300 micrometers), temperature (250 to 450° C.) and gas (1 to 15 seconds) and solids (2 to 60 seconds) residence times. Such a process leads to improved selectivity and propylene conversion.

Abstract: An improved method for the selective vapor phase oxidation of acrolein to acrylic acid in a recirculating solids reactor system using a particulate molybdenum vanadate multimetal oxide as oxidant involving specific reactant concentrations (preferably 5 mol % to 30 mol % propylene, 0 to 20 mol % oxygen, 0 to 70 mol % water, and the remainder inert gas), solids particle size (20 to 300 micrometers), temperature (250 to 450° C.) and gas (1 to 15 seconds) and solids (2 to 60 seconds) residence times. Such a process leads to improved selectivity, conversion and solids conversion ratio.

Abstract: An improved method for manufacturing acrylic acid by vapor phase oxidation of propylene in a single step or reaction stage using as solid phase oxidant a mixture of two particulate solids comprising a bismuth molybdate multimetal oxide (e.g., Mo12Co3.5Bi1.1Fe0.8W0.5Si1.4K0.05Ox) and a molybdenum vanadate multimetal oxide (e.g., Mo12V4.8Sr0.5W2.4Cu2.2Ox). Such a process is advantageously carried out in a recirculating solids reactor system wherein the particulate mixture of solids in an oxidized state reacts with a feed gas containing propylene in a vertical riser reactor and after separation from the acrylic acid gaseous product the particulate mixture of solids in a reduced state is regenerated by contact with an oxygen containing gas in a separate regeneration reactor before recirculation to the riser for further reaction.

Abstract: Solid mixed oxides composition of formula (I):

Abstract: Solid mixed oxides composition of formula (I):Mo.sub.12 V.sub.a Sr.sub.b W.sub.c Cu.sub.d Si.sub.e O.sub.x(I)2.ltoreq.a.ltoreq.14, 0.1.ltoreq.B.ltoreq.6, 0.ltoreq.c.ltoreq.12, 0.ltoreq.d.ltoreq.6, 0.ltoreq.e.ltoreq.15; x is the quantity of oxygen bonded to the other elements and depends on their oxidation states, are used in the manufacture of acrylic acid by oxidation of acrolein, the said solid composition reacting with acrolein according to the redox reaction (1):SOLID.sub.oxidized +ACROLEIN.fwdarw.SOLID.sub.reduced +ACRYLIC ACID(1).To manufacture acrylic acid, a gaseous mixture of acrolein and of water vapor and, if appropriate, of an inert gas is passed over a solid composition of formula (I), to conduct the redox reaction (1) by operating at a temperature of 200 to 500.degree. C., at a pressure of 1.01.times.10.sup.4 to 1.01.times.10.sup.6 Pa (0.1 to 10 atmospheres), and with a residence time of 0.01 second to 90 seconds, in the absence of molecular oxygen.