Abstract: The invention relates to a dispersion of the type comprising particles of a rare earth compound, particularly a compound of cerium, an acid and an organic phase, characterized in further comprising an anti-oxidant agent which can particularly be selected from substituted derivatives of phenol, aromatic amines or tocopherols. Said dispersion may be used as additive for diesel fuel for internal combustion engines, in particular as additive for diesel for diesel engines.

Abstract: The invention relates to a process for preparing 2-oxo-4-methylthiobutyric acid (I), its salts and its derivatives in which R represents a group chosen from COOH, COOR?, NH2, NHR? or NR?R?, where R? and R? are chosen, independently of one another, from the group of linear or branched alkyl radicals having from 1 to 12 carbon atoms and cycloalkyl radicals having from 3 to 12 carbon atoms, according to which process but-3-ene-1,2-diol (II) is catalytically and selectively oxidized to give 2-oxobut-3-enoic acid (III) and methyl mercaptan is selectively condensed with 2-oxobut-3-enoic acid (III). 2-Oxo-4-methylthiobutyric acid (I), its salts and its derivatives are used as food supplement, in particular in animal nutrition.

Abstract: The invention relates to a process for preparing 2-oxo-4-methylthiobutyric acid (I), its salts and its derivatives in which R represents a group chosen from COOH, COOR?, NH2, NHR? or NR?R?, where R? and R? are chosen, independently of one another, from the group of linear or branched alkyl radicals having from 1 to 12 carbon atoms and cycloalkyl radicals having from 3 to 12 carbon atoms, according to which process but-3-ene-1,2-diol (II) is catalytically and selectively oxidized to give 2-oxobut-3-enoic acid (III) and methyl mercaptan is selectively condensed with 2-oxobut-3-enoic acid (III). 2-Oxo-4-methylthiobutyric acid (I), its salts and its derivatives are used as food supplement, in particular in animal nutrition.

Abstract: Engines equipped with an exhaust line fitted with a particulate filter, in which the particulates contained in the exhaust gas are trapped on such filter, and wherein the trapped particulates are periodically burned off, are operated by improvedly catalyzing the combustion of said particles utilizing a composition containing mixture of a lubricating oil and a colloidal dispersion as the engine-lubricating composition, which dispersion includes particles of at least one compound of at least one rare earth and an amphiphilic agent.

Abstract: A method for treating/purification a gas containing nitrogen oxides (NOx) includes conveying same through a NOx trap containing a composition based on a catalyst for oxidizing NOx into NO2 and a compound based on zirconium oxide and praseodymium oxide in a proportion of praseodymium oxide ranging from 5 wt. % to 50 wt. % of oxide; such compound may further include cerium oxide and the subject process is useful for treating the exhaust gas of a Diesel or lean mixture gasoline internal combustion engine.

Abstract: Lubricant compositions contain a blend of a lubricating oil and a colloidal dispersion of particles of at least one iron compound and an amphiphilic agent; such compositions are useful for operating an engine, more particularly a diesel engine, which is equipped with an exhaust system fitted with a particle filter, wherein the particles present in the exhaust gases are trapped on the filter and, periodically, the trapped particles are burned, and further wherein the subject compositions are employed as engine lubricants with a view to catalyzing the combustion of the trapped particles.

Abstract: The colloidal dispersion of the invention is characterized in that it comprises an organic phase; particles of an iron compound in its amorphous form; and at least one amphiphilic agent. It is prepared by a process in which either an iron salt in the presence of an iron complexing agent or an iron complex is reacted with a base, maintaining the pH of the reaction medium at a value of at most 8 to obtain a precipitate, the iron complexing agent being selected from hydrosoluble carboxylic acids with a complexing constant K such that the pK is at least 3 and the iron complex being selected from the products of reacting iron salts with said acids; then the precipitate obtained or a suspension containing said precipitate is brought into contact with an organic phase in the presence of an amphiphilic agent to obtain the dispersion in an organic phase. The dispersion of the invention can be used as a combustion additive in liquid fuel or motor fuel.

Abstract: The invention relates to a process for preparing 2-oxo-4-methylthiobutyric acid (I), its salts and its derivatives in which R represents a group chosen from COOH, COOR?, NH2, NHR? or NR?R?, where R? and R? are chosen, independently of one another, from the group of linear or branched alkyl radicals having from 1 to 12 carbon atoms and cycloalkyl radicals having from 3 to 12 carbon atoms, according to which process but-3-ene-1,2-diol (II) is catalytically and selectively oxidized to give 2-oxobut-3-enoic acid (III) and methyl mercaptan is selectively condensed with 2-oxobut-3-enoic acid (III). 2-Oxo-4-methylthiobutyric acid (I), its salts and its derivatives are used as food supplement, in particular in animal nutrition.

Abstract: The inventive colloidal dispersion comprised cerium compound particles, an acid and an organic phase and is characterized in that it also comprises a compound of at least one element selected from rhodium and palladium. According to variants, the dispersion comprises particles of a compound of cerium, another rare earth and/or iron.

Abstract: The invention relates to a dispersion of the type comprising particles of a rare earth compound, particularly a compound of cerium, an acid and an organic phase, characterised in further comprising an anti-oxidant agent which can particularly be selected from substituted derivatives of phenol, aromatic amines or tocopherols. Said dispersion may be used as additive for diesel fuel for internal combustion engines, in particular as additive for diesel for diesel engines.

Abstract: The invention concerns an organic colloidal dispersion comprising: particles of at least a compound based on at least a rare earth, at least an acid, and at least a diluent, characterised in that at least 90% of the particles are monocrystalline. The invention also concerns the method for preparing said dispersion and its use as additive of diesel fuel for internal combustion engines.

Abstract: The colloidal dispersion of the invention is characterized in that it comprises an organic phase; particles of an iron compound in its amorphous form; and at least one amphiphilic agent. It is prepared by a process in which either an iron salt in the presence of an iron complexing agent or an iron complex is reacted with a base, maintaining the pH of the reaction medium at a value of at most 8 to obtain a precipitate, the iron complexing agent being selected from hydrosoluble carboxylic acids with a complexing constant K such that the pK is at least 3 and the iron complex being selected from the products of reacting iron salts with said acids; then the precipitate obtained or a suspension containing said precipitate is brought into contact with an organic phase in the presence of an amphiphilic agent to obtain the dispersion in an organic phase. The dispersion of the invention can be used as a combustion additive in liquid fuel or motor fuel.

Abstract: A process for the combustion treatment of carbonaceous particles collected on a filter situated in an exhausted circuit of an internal combustion engine is disclosed. The combustion of the particles is brought about by contacting them with a gas mixture including at least nitrogen dioxide generated within the exhaust circuit of the engine, the particles having been seeded prior to their combustion with at least one catalyst of their oxidation.

Abstract: The present invention relates to a composition based on cerium oxide or on cerium and zirconium oxides, in the extruded form, to a process for the preparation thereof and to the use thereof as catalyst. The process for the preparation of the composition of the invention is characterized in that a cerium hydroxide or oxyhydroxide or cerium and zirconium hydroxides or oxyhydroxides are extruded. The composition of the invention can be used as catalyst or catalyst support, in particular in the treatment of exhaust gases from internal combustion engines, in the process for the dehydrogenation of ethylbenzene to styrene, in the catalysis of methanation or in the treatment of a solution or suspension of organic compounds by oxidation via a wet route.

Abstract: The present invention relates to a composition based on cerium oxide or on cerium and zirconium oxides, in the extruded form, to a process for the preparation thereof and to the use thereof as catalyst. The process for the preparation of the composition of the invention is characterized in that a cerium hydroxide or oxyhydroxide or cerium and zirconium hydroxides or oxyhydroxides are extruded. The composition of the invention can be used as catalyst or catalyst support, in particular in the treatment of exhaust gases from internal combustion engines, in the process for the dehydrogenation of ethylbenzene to styrene, in the catalysis of methanation or in the treatment of a solution or suspension of organic compounds by oxidation via a wet route.

Abstract: The present invention relates to a process for the treatment of exhaust gases from internal combustion engines operating with a fuel containing sulphur. This process is characterized in that use is made, as catalyst, of a composition based on a cerium oxide and on a zirconium oxide, in a cerium/zirconium atomic proportion of at least 1, and on at least one oxide chosen from yttrium, lanthanum and praseodymium oxide and which exhibits a specific surface, after calcination for 6 hours at 900 ° C., of at least 35 m2/g.

Abstract: A composition based on cerium oxide and on zirconium oxide and, optionally, on a yttrium, scandium or rare-earth metal oxide. The cerium/zirconium atomic proportion is at least 1. The compound exhibits a specific surface, after calcination for 6 hours at 900° C. of at least 35 m2/g and an oxygen storage capacity at 400° C. of at least 1.5 ml of O2/g. The composition is prepared by mixing, in a liquid medium, a cerium compound, a zirconium compound and, if appropriate, a yttrium, scandium or rare-earth metal compound; heating and calcining the precipitate obtained; and using a zirconium solution having an amount of base necessary to reach the equivalent point during an acid/base titration of the solution having a molar ratio of OH−/Zr≦1.65. The composition thus obtained is used in the manufacture of multi-functional catalysts.

Abstract: The invention relates to a composition based on zirconium oxide and comprising cerium oxide which has a specific surface of at least 30 m2/g after calcination for 6 hours at 900° C. and which is provided in the form of a pure solid solution of cerium oxide in zirconium oxide. According to another embodiment, this composition can additionally comprise a doping element and can exhibit a specific surface of at least 25 m2g after calcination for 6 hours at 1000° C. A process for the preparation of these compositions comprises the following stages: a mixture is prepared, in liquid medium, containing a zirconium compound and a cerium(IV) compound; the said mixture is heated at a temperature greater than 100° C.

Abstract: Solid catalysts suited for the fluidized/moving bed catalytic ammoxidation of alkanes comprise an active catalytic phase having the empirical formula (I): VSbaSnbTicFedEeOx  (I) in which E is an element which provides an oxide of rutile structure or an element which, in combination with V, Sb, Sn, Ti, Fe and/or with another element E, provides a phase of rutile or trirutile structure, or a solid solution of rutile structure, a is a whole or fractional number equal to or greater than 0.

Abstract: The present invention relates to a process for the preparation of mixed vanadium, antimony and iron oxides and to their use as catalysts for the ammoxidation of alkanes. The process for the preparation of a mixed oxide defined above is characterized in that:respective vanadium, antimony and iron compounds are dissolved in at least one saturated alcohol or in water,the alcoholic .epsilon.olution or the aqueous solution thus obtained is brought into contact with an aqueous solution containing an ammonium salt, in order to precipitate the mixed oxide,the mixed oxide obtained is separated and calcined.