Abstract: The invention relates to a method of obtaining a homogeneous filtering structure for a catalytic application, which can be used as a particulate filter in an internal combustion engine exhaust line, said structure comprising a plurality of honeycomb filter elements in which a homogeneity criterion characteristic of the constituent support material of said elements, in the absence of a catalytic coating, is determined in a prior step, and then the elements making up the structure are selected by means of this homogeneity criterion so as to obtain a structure suitable for homogeneous deposition, within an element and from one element to another, of a catalyst for treating the pollutants in gas phase. The invention also relates to the homogeneous filtration structure obtained by said method.

Abstract: The invention relates to a honeycomb structure, made from a porous ceramic material, said structure being characterized in that the porous ceramic material which forms it comprises: from 50 to 95% by weight of silicon carbide SiC; from 5 to 50% by weight of at least one ceramic oxide phase, said structure additionally being characterized by a porosity greater than 10%, by a specific surface area greater than 0.5 m2/g and by a pore size distribution of at least bimodal type. The invention also relates to the process for obtaining such a structure and also to the catalytic support or filter obtained from such a structure, after deposition of a catalyst.

Abstract: A structure for the purification of a polluted gas comprising a porous matrix of an inorganic material, in the form of interconnected grains and an electrochemical system for the treatment of said gas, formed by a reduction catalyst A for reducing the polluting species of the NOx type, an oxidation catalyst B for oxidizing the polluting species of the hydrocarbon HC type or CO type, an electron-conductive compound C and an ion-conductive compound D, said structure being characterized in that catalysts A and B are placed in the pores of the inorganic material, in that the grains and possibly the grain boundaries of the inorganic material constituting the matrix are covered over at least part of their surface with a texturizing material, and in that said texturizing material is an ionic, electronic or ionic/electronic conductor and constitutes, respectively, the element C, the element D or the elements C and D of the electrochemical gas treatment system.

Abstract: Catalytic filter comprising a porous matrix consisting of an inorganic material, in the form of grains that are interconnected so as to provide cavities between them, such that the open porosity is between 30 and 60% and the median pore diameter is between 5 and 40 ?m, said filter being characterized in that the grains and possibly the grain boundaries of the inorganic material are covered over at least part of their surface with a texturizing material, said texturizing consisting of irregularities having dimensions of between 10 nm and 5 microns and in that a catalytic coating at least partially coats the texturizing material and optionally, at least partially, the grains of the inorganic material.

Abstract: The invention relates to a process for obtaining a structure made from a porous ceramic material comprising at least 95% of silicon carbide SiC, said process being characterized in that said structure is obtained from a mixture of SiC grains comprising at least: a first fraction of ?-SiC grains whose median diameter is less than 5 microns; a second fraction of ?-SiC grains whose median diameter is at least two times greater than that of the first fraction of ?-SiC grains and whose median diameter is greater than or equal to 5 microns; and a fraction of ?-SiC grains or of at least a precursor of ?-SiC grains. The invention also relates to the porous structure obtained according to the process.

Abstract: The invention relates to a structure for the purification of a contaminated gas, for example the exhaust gas from a diesel or petrol engine, the structure incorporating an electrochemical system for treating said gas, composed of an NOx reduction catalyst A, a hydrocarbon oxidation catalyst B, an electron-conducting compound C and an ion-conducting compound D, said structure being characterized in that it is made of or covered with at least one porous, inorganic, electron-conducting and/or ion-conducting material in such a way that the catalysts A and B are disposed in the porosity of the inorganic material and that the ion-conducting, electron-conducting or ion-conducting and electron-conducting inorganic material makes up, respectively, the element C, the element D, or the sum of the elements C and D of said electrochemical system.

Abstract: The invention relates to a method of obtaining a homogeneous filtering structure for a catalytic application, which can be used as a particulate filter in an internal combustion engine exhaust line, said structure comprising a plurality of honeycomb filter elements in which a homogeneity criterion characteristic of the constituent support material of said elements, in the absence of a catalytic coating, is determined in a prior step, and then the elements making up the structure are selected by means of this homogeneity criterion so as to obtain a structure suitable for homogeneous deposition, within an element and from one element to another, of a catalyst for treating the pollutants in gas phase. The invention also relates to the homogeneous filtration structure obtained by said method.

Abstract: The invention relates to a honeycomb structure, made from a porous ceramic material, said structure being characterized in that the porous ceramic material which forms it comprises: from 50 to 95% by weight of silicon carbide SiC; from 5 to 50% by weight of at least one ceramic oxide phase, said structure additionally being characterized by a porosity greater than 10%, by a specific surface area greater than 0.5 m2/g and by a pore size distribution of at least bimodal type. The invention also relates to the process for obtaining such a structure and also to the catalytic support or filter obtained from such a structure, after deposition of a catalyst.

Abstract: The invention concerns a catalytic filter for depolluting a gas loaded with soot particles and gaseous pollutants, obtained by impregnating in a catalytic solution a filtering structure formed by an assembly of honeycomb-type monolithic elements, wherein the porosity of the cement used as coating and/or as joint and/or as plug is less than the porosity of the material constituting said element(s).

Abstract: The invention relates to the shape selective acylation of an organic compound. In particular, the invention describes a process for such acylation wherein the process comprises reducing the number of surface acid sites without dealuminations on at least a portion of the surface of a zeolite and acylating the organic compound in the presence of the zeolite. The organic compounds used in the invention include, for example, olefins, aromatic hydrocarbons, aromatic heterocyclic compounds, and phenolic compounds wherein the organic group may be substituted or unsubstituted. The zeolite may be any natural or synthetic zeolite with a unidimensional or multidimensional network, for example a two-dimensional, or three-dimensional network, or any molecular sieve with structural features similar to these.

Abstract: The invention concerns a process for skeletal isomerisation of linear olefins using a catalyst containing at least one pre-treated molecular sieve selected from the group formed by SAPO-31, SAPO-11, Theta-1, EU-1, omega zeolite, mordenite, Nu-10, Nu-86, Nu-87, ferrierite, ZSM-12 and ZSM-23.

Abstract: The invention concerns a process for skeletal isomerization of linear olefins using a catalyst containing at least one pre-treated molecular sieve selected from the group formed by SAPO-31, SAPO-11, Theta-1, EU-1, omega zeolite, mordenite, Nu-10, Nu-86, Nu-87, ferrierite, ZSM-12 and ZSM-23. The pre-treatment process consists in bringing the molecular sieve, which has a pore size of 0.4 to 0.8 nm, into contact with at least one hydrocarbon molecule containing 4 to 20 carbon atoms, at a space velocity of 0.1-45 h.sup.-1, a temperature of 300.degree.-550.degree. C. and at a pressure of 0.1-1 MPa, for 0.5-48 h, to deposit coke in the pores. The process is of particular application to one-dimensional sieves. It is preferably carried out outside the reaction zone. The invention also concerns a catalyst containing a pre-treated sieve, the sieve being selected from SAPO-31, SAPO-11, Theta-1, EU-1, omega zeolite, mordenite, ferrierite, Nu-10, Nu-86 and Nu-87.