Abstract: A process for the preparation by ethylene polymerization of at least one dialkyl magnesium compound of formula R—(CH2—CH2)n—Mg—(CH2—CH2)m—R? in which R and R?, identical or different, represent aryl, benzyl, allyl or alkyl groups and in which the integers n and m, identical or different, represent average —CH2—CH2— chain formation numbers greater than 1, the process including a single stage of mixing the following components: at least one ligand or one ligand precursor, at least one rare earth salt, at least one dialkyl magnesium compound of formula R—Mg—R?, and ethylene, in a medium allowing contact between the components of the above mixture.

Abstract: The invention concerns a novel catalytic combination for polymerizing alpha-olefins based on a titanium diamidide complex. The invention also concerns a method for polymerizing alpha-olefins using said catalytic combination, in the absence of any aluminum-containing compound. The inventive catalytic combination comprises: component A which is a dichlorinated titanium diamidide complex of general formula (I) wherein R represents a methyl group (component A2) or an isopropyl group (component A1); component B which is a dialkylmagnesium whereof the reaction with component A enables an alkylated component AA to be obtained: and as activator of said component AA, component C which is trispentafluorophenylboran (B(C6F5)3).

Abstract: The invention concerns a novel catalytic combination for polymerizing alpha-olefins based on a titanium diamidide complex. The invention also concerns a method for polymerizing alpha-olefins using said catalytic combination, in the absence of any aluminum-containing compound. The inventive catalytic combination comprises: component A which is a dichlorinated titanium diamidide complex of general formula (I) wherein R represents a methyl group (component A2) or an isopropyl group (component A1); component B which is a dialkylmagnesium whereof the reaction with component A enables an alkylated component AA to be obtained: and as activator of said component AA, component C which is trispentafluorophenylboran (B(C6F5)3).

Abstract: The invention relates to a method of preparing a block copolymer, the first block of which is a polymer or a copolymer having at least one diene and the second block of which is a polymer with a polar monomer. The inventive method is characterised in that: first, the polymerisation or the copolymerisation of the first block is carried out in the presence of a catalyst comprising the product of the reaction of a rare earth alcoholate and an alkylating agent selected from among organolithiums, organomagnesiums, organozincs, organoaluminiums and borons; and, secondly, the copolymerisation of the polar monomer is performed with the first block in the presence of the same catalyst. The invention also relates to a block copolymer consisting of a first block comprising a polymer or a linear copolymer having at least one diene and a second block comprising a polymer presenting several hydroxy, epoxy and/or alkoxysilyl functions.

Abstract: The invention relates to a method of preparing a block copolymer, the first block of which is a polymer or a copolymer having at least one diene and the second block of which is a polymer with a polar monomer. The inventive method is characterised in that: first, the polymerisation or the copolymerisation of the first block is carried out in the presence of a catalyst comprising the product of the reaction of a rare earth alcoholate and an alkylating agent selected from among organolithiums, organomagnesiums, organozincs, organoaluminiums and borons; and, secondly, the copolymerisation of the polar monomer is performed with the first block in the presence of the same catalyst. The invention also relates to a block copolymer consisting of a first block comprising a polmyer or a linear copolymer having at least one diene and a second block comprising a polymer presenting several hydroxy, epoxy and/or alkoxysilyl functions.

Abstract: A method for preparing tris[(1H,1H,2H,2H-perfluoroalkyl)aryl]phosphites consists in preparing a grignard reagent from an alkoxyhalogenobenzene, then reacting it with a iodo-1H,1H,2H,2H-perfluoroalkane; transforming the alkoxy function of (1H,1H,2H,2H,2H-perfluoroalkyl)alkoxybenzene obtained into a hydroxy function, then reacting (1H,1H,2H,2H-perfluoroalkyl)hydroxybenzene with PCl3. The invention also concerns fluorinated arylphosphites and their use as transition metal ligand for making catalysts to be used in two-phase catalysis with fluorinated phase.

Abstract: A ligand adapted for use in a process for enantioselective reduction of unsaturated compounds carrying functional groups by a hydrogen transfer method including an optically active N-substituted chiral derivative of norephedrine and the associated process.

Abstract: The invention concerns a method for preparing an optically active alcohol of formula (I) in which the carbon atom indicated by the symbol * can have the configuration (R) or (S) and X represents a non-substituted amino group or a mono- or di-(C.sub.1 -C.sub.4)alkylamino group optionally salified from corresponding ketones by catalytic hydrogenation in the presence of a rhodium complex.

Abstract: This dialkylmagnesium is represented by the formula R--(CH.sub.2 --CH.sub.2).sub.n --Mg--(CH.sub.2 --CH.sub.2).sub.n' --R', (E--O--E').sub.x, where R and R' each independently represent a C.sub.1 -C.sub.20 hydrocarbon residue, branched or not, substituted or not, of the alkyl, cycloalkyl or aralkyl type; n and n', identical or substantially identical, represent an average number of --CH.sub.2 --CH.sub.2 -- linkages such that the average number of carbon atoms in each of the two chains borne by Mg is greater than 20; E and E', identical or different, each represent an alkyl radical, linear or cyclical, branched or not; and 0.ltoreq.x.ltoreq.2, x being the average value of the number of moles of E--O--E' ether complexed to the dialkylmagnesium. In order to prepare a dialkylmagnesium of this type, ethylene is polymerized in an anhydrous, de-oxygenated hydrocarbonaceous solution by means of a catalyst Cp*.sub.2 MCl.sub.2 Li(OEt.sub.2).sub.

Abstract: The invention relates to a process for the hydroformylation of an olefin chosen from the alkenes represented by the formula CnH.sub.2n in which n is an integer less than or equal to 30, or chosen from functionalized olefins, by a CO/H.sub.2 gas mixture in a two-phase medium, this process consisting in placing in contact, on the one hand, an aqueous solution containing a catalytic system consisting of a water-soluble transition metal complex and a water-soluble phosphine, and, on the other hand, an olefin, in heating the reaction mixture obtained with stirring, after it has been placed under a pressure of the CO/H.sub.2 gas mixture, in which process a modified cyclodextrin is introduced into the aqueous solution containing the catalytic system.

Abstract: This dialkylmagnesium is represented by the formula R--(CH.sub.2 --CH.sub.2).sub.n --Mg--(CH.sub.2 --CH.sub.2).sub.n' --R', (E--O--E').sub.x, where R and R' each independently represent a C.sub.1 -C.sub.20 hydrocarbon residue, branched or not, substituted or not, of the alkyl, cycloalkyl or aralkyl type; n and n', identical or substantially identical, represent an average number of --CH.sub.2 --CH.sub.2 -- linkages such that the average number of carbon atoms in each of the two chains borne by Mg is greater than 20; E and E', identical or different, each represent an alkyl radical, linear or cyclical, branched or not; and 0.ltoreq.x.ltoreq.2, x being the average value of the number of moles of E--O--E' ether complexed to the dialkylmagnesium. In order to prepare a dialkylmagnesium of this type, ethylene is polymerized in an anhydrous, de-oxygenated hydrocarbonaceous solution by means of a catalyst Cp*.sub.2 MCl.sub.2 Li(OEt.sub.2).sub.

Abstract: A process is disclosed for the polymerization of olefins, using (i) a catalyst and (ii) an organometallic activator from Groups I, II or III of the Periodic Table at temperatures between 20.degree. and 250.degree. C., and pressure up to 200 bar, in solution, or in suspension in an inert liquid hydrocarbon, at temperatures between 160.degree. and 350.degree. C., under pressures of between 400 and 3000 bar, in a continuous manner in a reactor where the mean residence time of the catalyst is between 1 and 150 seconds. The catalyst comprises at least one titanium compound, at least one halogen-containing organoaluminum compound and at least one inorganic magnesium compound in suspension in at least one .alpha.,.omega.-dihaloalkane. The titanium compound is essentially a titanium (III) compound, the total content of titanium (II) and titanium (IV) being less than or equal to 15% of the total content of titanium.

Abstract: This catalyst consists of the reaction product, with at least one organomagnesium compound and/or organolithium compound R.sup.1 Li (R.sup.1 =alkyl) or ArLi (Ar=phenyl or benzyl), of the reaction product of (Cp).sub.2 MX.sub.2 Li(OR.sub.2).sub.2 (M=lanthanide, Sc, Y; (Cp)=optionally substituted cyclopentadienyl; and R=alkyl), with at least one bidentate ligand, such as .beta.-diketone or .beta.-keto imine CZ.sub.3 COCHZCDCZ.sub.3, Z selected from halogen, alkyl and H, D=O, NH or NR.sup.3 (R.sup.3 =alkyl or aryl); and phosphorus ylid R.sup.2.sub.3 P.dbd.CA--CO--R.sup.2, R.sup.2 chosen from alkyl and aryl; A=alkyl or H. It advantageously takes the form of a solution at least partially containing an aromatic hydrocarbon. The process for the polymerization of ethylene may be carried out at 20.degree.-250.degree. C. at a pressure which may range up to approximately 200 bars, in solution or in suspension in an at least C.sub.

Abstract: Process for the preparation of a catalytic composition for the polymerization of olefins. At least partial electrochemical oxidation of aluminum in a solvent of .alpha.,.omega.-dihalogeno-alkane and simultaneously the electrochemical reduction of a compound of titanium (IV) occur in process.The catalytic composition comprises at least one titanium compound, at least one halogenated organo-aluminum compound and at least one inorganic magnesium compound in suspension in at least one .alpha.,.omega.-dihalogeno-alkane. The titanium compound is essentially a titanium (III) compound. The overall content of titanium (II) and titanium (IV) is less than or equal to 15% of the total titanium content.

Abstract: The process comprises, in a first step, the reduction of a titanium (IV) compound in an .alpha.,.omega.-dihalogenoalkane using a molar excess of at least one halogenated organoaluminium compound in the absence of an ether, and then in a second step, the addition of a reaction mixture of a compound capable of forming a magnesium halide in-situ, without additional reduction of the titanium compound obtained in the first step. The catalyst contains at least one titanium compound, at least one halogenated organoaluminium compound and at least one inorganic magnesium compound in suspension in at least one .alpha.,.omega.-dihalogenoalkane; the titanium cmpound is essentially a titanium (III) compound, the total titanium (II) and titanium (IV) content being less than or equal 15% to the total titanium content. It may also contain at least one vanadium compound, an inert solvent, at least one partially polymerized .alpha.

Abstract: Process for the preparation of a catalytic composition for the polymerization of olefins. At least partial electrochemical oxidation of aluminum in a solvent of .alpha., .omega.-dihalogeno-alkane and simultaneously the electrochemical reduction of a compound of titanium (IV) occur in process.The catalytic composition comprises at least one titanium compound, at least one halogenated organs-aluminum compound and at least one inorganic magnesium compound in suspension in at least one .alpha.,.omega.-dihalogeno-alkane. The titanium compound is essentially a titanium (III) compound. The overall content of titanium (II) and titanium (IV) is less than or equal to 15% of the total titanium content.

Abstract: The invention relates to a process for the preparation of acetic anhydride, characterized in that a gas containing essentially CO, at a pressure of at least 1 MPa, is reacted with methyl formate in the presence ofa) a rhodium-based catalyst,b) two iodine-containing promoters of different kind, successively ionic and covalent, andc) an N-substituted cyclic amide as solvent.

Abstract: Chiral phosphorus-containing ligands comprising at least one amine radical and at least one dihydrocarbylphosphinoxy radical of the formula W=OP (R).sub.

Abstract: The object of the invention is a process for the preparation of methyl acetate starting from the methyl formate, characterized in that methyl formate is converted at a temperature of 170.degree. to 220.degree. C. in the presence of:a) a catalyst based on rhodium,b) an iodine-containing promoter selected from among the alkaline, alkaline earth, phosphonium or ammonium iodides and the mixtures of covalent compounds of iodine supplemented with a phosphine or a tertiary amine.c) a solvent selected from a cyclic N-alkyl amide.

Abstract: Saturated carboxylic esters are produced from alkyl formate and an olefin, without the presence of substantial amounts of carbon monoxide, at a temperature of 120.degree. to 280.degree. C., under a pressure of 1 to 3,000 bars, in the presence of a catalyst based on ruthenium coordinated by ligands selected from carbon monoxide, halogen atoms and amines, and in the presence of an amide as a solvent. The catalyst is selected from catalysts consisting essentially of RuCl.sub.3.3H.sub.2 O; catalysts consisting essentially of the combination of an RuCl.sub.3.3H.sub.2 O together with at least one stabilizer selected from iodine, covalent iodides and quaternary ammonium halides; catalysts comprising Ru.sub.3 (CO).sub.12 together with at least one stabilizer such as is mentioned above; and catalysts selected from RuI.sub.3, [RuCl.sub.2 (CO).sub.3 ].sub.2, Ru(NH.sub.3).sub.6 Cl.sub.3 and [Ru(NH.sub.3).sub.5 Cl]Cl.sub.2, comprising, where appropriate, in addition, at least one stabilizer such as is mentioned above.