Abstract: A method for the preparation of the 2-hydroxy-4-methylthiobutyronitrile (HMTBN) or its selenium equivalent (HMSeBN) from hydrocyanic acid and 3-methylthiopropanal (MTP) or the corresponding selenium aldehyde (MSeP) includes the following steps: the molar ratio of the HCN to MTP or to MSeP is adjusted to a value greater than or equal to 1 and the pH is adjusted and maintained at a value greater than or equal to 3.5, to obtain a reaction medium in which the HMTBN or the HMSeBN is formed, then the pH of the reaction medium is lowered to a value less than or equal to 2.5 and the HCN is extracted from the reaction medium, and the HMTBN or the HMSeBN is recovered. The applications of this method are also related.

Abstract: A method for preparing 2-hydroxy-4-methylthiobutyric acid (HMTBA) or 2-hydroxy-4-methylselenobutyric acid (HMSeBA) by catalytic conversion of 2-hydroxy-4-methylthiobutyronitrile or 2-hydroxy-4-methylselenobutyronitrile, respectively, where said conversion is carried out in the presence of water and at least one weak acid and one catalyst comprising at least one of alumina, titanium dioxide and zirconia.

Abstract: The invention concerns a preparation of a compound of formula I, [Chem 1] CH3XCH2CH2C(NH2)COOH??(I) where X represents S or Se, by catalytic conversion of a compound of formula II [Chem 2] CH3XCH2CH2C(Y)CN??(II) where X represents S or Se and Y represents NH2 or OH, when Y represents NH2, the conversion being carried out in the presence of water and of at least one catalyst comprising at least alumina, titanium dioxide or a mixture thereof, and when Y represents OH, the conversion being carried out in the presence of water, of at least one catalyst comprising at least alumina, titanium dioxide, zirconia or a mixture thereof, and NH3 or an ammonium salt.

Abstract: A method for producing a multiphase mixed-oxide catalyst including at least one active phase based on bismuth molybdate and one co-catalyst based on iron molybdate and at least one amongst the two elements cobalt and nickel, includes the following steps: preparing a mixture of the precursors of said-mixed oxides in a solvent, making said precursors react through a microwave-assisted hydrothermal reaction, and isolating the mixed oxides to obtain the catalyst. A catalyst and a catalytic system prepared in this manner are related to the method as well as the uses of this catalyst and of this catalytic system, in particular in the oxidation of propene into acrolein.

Abstract: A method for preparing a compound of formula RSH where R represents an alkyl group, by gas-phase catalytic reaction of hydrogen sulfide with a compound of formula ROH, in the presence of a solid catalyst, according to which method the reaction is performed in the presence of a catalyst which includes one or several pure or mixed rare-earth oxide(s), one or several pure or mixed rare-earth sulfide(s), or one or several pure or mixed rare-earth oxysulfide(s). When the rare earth is lanthanum, the catalyst is a mixed oxide of lanthanum and of at least one metal selected from rare earths or not and when the rare earth is cerium, the catalyst is supported on an alumina.

Abstract: An agent for initiating a radical addition reaction includes a persulfate and one or more transition metals, in elemental form or in an oxidized form, as well as a method for preparing a compound of formula (I) in which X is selected from S, Se and O; by a radical addition reaction in the presence of such an agent.

Abstract: A method for manufacturing 2-hydroxy-4-(methylthio)butyric acid (HMTBA) from 2-hydroxy-4-methylthio-butyronitrile (HMTBN), where HMTBN is hydrolyzed into HMTBA in the presence of a mineral acid in an aqueous medium, the medium is neutralized by addition of a base, a first phase including at least HMTBA and salts and a second phase containing salts are separated, the method including the separation of the HMTBA from the salts of the first phase, by subjecting the latter to a chromatography.

Abstract: A method for manufacturing 2-hydroxy-4-(methylthio)butyric acid (HMTBA) from 2-hydroxy-4-methylthio-butyronitrile (HMTBN), where HMTBN is hydrolyzed into HMTBA in the presence of a mineral acid in an aqueous medium, the medium is neutralized by addition of a base, a first phase including at least HMTBA and salts and a second phase containing salts are separated, the method including the separation of the HMTBA from the salts of the first phase, by subjecting the latter to a chromatography.

Abstract: The invention concerns a synthesis process of a compound of the following formula (I) or one of the salts thereof, wherein R represents a COOH, CH2OH or CHO group, comprising the step according to which the but-3-ene-1,2-diol (BDO) is subjected to an oxidation in the presence of a catalyst, said catalyst comprising an active phase based on at least one noble metal selected from palladium, gold, silver, platinum, rhodium, osmium, ruthenium and iridium, and a support containing alkaline sites. The invention also concerns the application of this reaction to the preparation of bioavailable compounds of methionine used, in particular, in animal nutrition.

Abstract: The invention relates to a method for preparing an olefine, a diene or a polyene, by catalytic conversion of at least one alcohol having a carbon chain of at least three carbon atoms and different from propan-2-ol, in the presence of at least one catalyst based of at least one phosphate of a metal or several metals M, M being chosen from among the 15 lanthanides (Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium), Yttrium, Scandium and Boron, and the applications of this method.

Abstract: The invention concerns a synthesis process of a compound of the following formula (I) or one of the salts thereof, wherein R represents a COOH, CH2OH or CHO group, comprising the step according to which the but-3-ene-1,2-diol (BDO) is subjected to an oxidation in the presence of a catalyst, said catalyst comprising an active phase based on at least one noble metal selected from palladium, gold, silver, platinum, rhodium, osmium, ruthenium and iridium, and a support containing alkaline sites. The invention also concerns the application of this reaction to the preparation of bioavailable compounds of methionine used, in particular, in animal nutrition.

Abstract: A method of preparing acrolein from glycerol or glycerine is disclosed. The method includes dehydrating glycerol or glycerine in the presence of a catalyst consisting of at least (a) a mixed oxide of zirconium and at least one metal, said metal being selected from niobium, tantalum and vanadium, or (b) a zirconium oxide and at least one metal oxide, the metal being selected from niobium, tantalum and vanadium, or (c) a silicon oxide and a mixed oxide of zirconium and at least one metal, the metal being selected from tungsten, cerium, manganese, niobium, tantalum, titanium, vanadium and silicon, or (d) a titanium oxide and a mixed oxide of zirconium and at least one metal, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, titanium, vanadium and silicon.

Abstract: A continuous process for obtaining acrolein by catalytic dehydration of glycerol or glycerin, in the presence of an acid catalyst, wherein said process comprises the concomitant regeneration of said catalyst and is carried out in a fluidized bed reactor, said reactor comprising two zones, a first zone, or lower zone, termed catalyst regeneration zone, in which a fluidization gas comprising oxygen is introduced, and a second zone, or upper zone, termed reaction zone, in which the glycerol or glycerin is introduced and converted into acrolein.

Abstract: Thermally stable, solid alumina-based compositions useful for the trapping of nitrogen oxides that are contained in gaseous fluids, notably in vehicular exhaust gases, are formed of alumina, cerium and a divalent metal M selected from among barium, strontium or an association of these two elements and which include at least 10% of the weight of element M expressed by weight of oxide in contrast to the total weight of the composition and also wherein the aluminate compound of the metal element M, i.e., MAl2O4, is absent and not detectable by X-ray diffraction of the composition, after calcination thereof with air at 700° C. for two hours.

Abstract: The invention relates to a method for preparing an olefine, a diene or a polyene, by catalytic conversion of at least one alcohol having a carbon chain of at least three carbon atoms and different from propan-2-ol, in the presence of at least one catalyst based of at least one phosphate of a metal or several metals M, M being chosen from among the 15 lanthanides (Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium), Yttrium, Scandium and Boron, and the applications of this method.

Abstract: The invention concerns a method for preparing acrolein from glycerol or glycerine, wherein dehydration of the glycerol or glycerine is achieved in the presence of a catalyst based on zirconium oxide and which active phase consists in at least a) a silicon oxide, a zirconium oxide and at least one metal M oxide, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, vanadium and titanium, b) a titanium oxide, a zirconium oxide and at least one metal M oxide, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, vanadium and silicon. This method can be used for making 3-(methylthio)propionic aldehyde MMP, 2-hydroxy-4-methylthiobutyronitrile HMTBN, methionine and its analogs.

Abstract: A method for preparing a mixture (M) comprising at least an alcohol (Aj), said method comprising the following steps: i) a step in which at least an alcohol (Ai) in gaseous state is oligomerized, thereby producing a mixture (A); ii) a step in which the mixture (A) is condensed to a gaseous stream and to a liquid stream corresponding to a condensed mixture (A); and iii) a step in which the condensed mixture (A) is hydrogenated in the liquid state.

Abstract: A method for preparing a mixture (M) including at least one alcohol (Aj), wherein said method includes a gas-phase oligomerization reaction of at least one alcohol (Ai) with a solid acid-base catalyst doped with one or more metals, said reaction being carried out in the presence of hydrogen and at a temperature of no less than 50° C. and strictly less than 200° C.

Abstract: A process for preparing a mixture (M) comprising at least one alcohol (Aj), wherein said process comprises a reaction for oligomerization in the gas phase of at least one alcohol (Ai), carried out in the presence of a solid catalyst doped with one or more metals, at a temperature greater than or equal to 50° C. and strictly below 200° C. The oligomerization reaction is carried out in the absence of hydrogen.

Abstract: A method for preparing a mixture (M) comprising at least an alcohol (Aj), said method comprising the following steps: i) a step in which at least an alcohol (Ai) in gaseous state is oligomerized, thereby producing a mixture (A); ii) a step in which the mixture (A) is condensed to a gaseous stream and to a liquid stream corresponding to a condensed mixture (A); and iii) a step in which the condensed mixture (A) is hydrogenated in the liquid state.