Abstract: The invention discloses a method for purifying adipic acid by crystallization or recrystallization in at least one carbolyxic acid. More precisely, it discloses an improvement in adipic acid crystallization or recrystallization, characterised in that the said crystallization or recrystallization is effected in at least one carboxylic acid with a melting point below 20° C. The presence of carbon monoxide during crystallization or recrystallization can have a favourable effect on the adipic acid purity, in particular by reducing the content of metal catalyst traces of the adipic acid. The adipic acid purity can also be improved when the crystallization or recrystallization is effected in presence of a strong proton acid.

Abstract: A method for preparing acetic acid and/or methyl acetate by simultaneous isomerization and carbonylation reactions. A reaction mixture is provided containing at least one reagent which provides formyl radicals and at least one further reagent which provides methyl radicals, together with water in an amount of at most 5% by weight, carbon monoxide at a partial pressure between 0.1·105 Pa and 25·105 Pa, a solvent and a catalytic system which contains at least one halogenated promoter and at least one iridium-based compound. In a typical reaction mixture, methyl formate is isomerized to form acetic acid according to the reaction: HCOOCH3CH3COOH while methanol undergoes carbonylation to form acetic acid according to the reaction: CH3OH+COCH3COOH The reagent which provides the formyl radicals is kept at or below 20% by weight of the reaction mixture, while the molar ratio of methyl radicals to formyl radicals in the mixture is greater than 1.

Abstract: The invention discloses pentenoic acid hydroxycarbonylation into adipic acid. More particularly, it concerns one pentenoic acid hydroxycarbonylation method involving reaction water and carbon monoxide, in the presence of a catalyst comprising at least rhodium and/or iridium and an iodinated or brominated catalytic promoter. In the method, the catalyst is derived at least in part from a previous pentenoic acid hydroxycarbonylation operation. The reaction is effected in the presence of an amount of branched carboxylic diacids having 6 carbon atoms not exceeding 200 grams per kilogram reaction mixture.

Abstract: A method for the preparation of acetic acid and/or methyl acetate by isomerization of methyl formate in a reaction mixture which includes water, a solvent and a catalytic system containing a halogenated promoter and an iridium-based compound. Carbon monoxide is present in the reaction mixture at a partial pressure between 0.1.105 Pa and 25.105 Pa, methyl formate is maintained below 20% by weight of the reaction mixture and water is maintained in an amount which is at most 5% by weight of the reaction mixture. In a typical system, method formate isomerizes to acetic acid according to the reaction: HCOOCH3CH3COOH.

Abstract: The invention discloses a method for purifying adipic acid in water. More precisely it discloses an improvement in adipic acid crystallization or recrystallization in water, characterised in that the said crystallization or recrystallization is effected in presence of a strong proton acid and/or in the presence of carbon monoxide. This crystallization or recrystallization particularly enables the content of metal catalyst traces in the adipic acid to be reduced.

Abstract: The present invention relates to a process for the hydroxycarbonylation of pentenoic acids. By the process, one or a number of pentenoic acids are hydroxycarbonylated to adipic acid, by carbon monoxide and water, in the presence of a catalyst based on iridium and/or rhodium and of at least one iodinated promoter. The reaction mixture obtained is subjected to a refining operation, after having optionally been concentrated, making it possible to separate at least a part of the catalyst. The catalyst thus separated is recycled to an operation for the hydroxycarbonylation of pentenoic acids, of butadiene, or of butadiene derivatives.

Abstract: A method for preparing carboxylic acids by carbonylating a reagent, particularly an alcohol, in the presence of a rhodium catalyst. According to the method, the liquid phase reaction is carried out in a first zone in the presence of a rhodium catalyst, and the resulting reaction mixture is partially vaporised in a second zone. The vaporised fraction containing the carboxylic acid is later purified and the unvaporised liquid fraction containing the catalyst is recirculated to the first zone. The method is charactracterised in that said unvaporised fraction is contacted with carbon monoxide in such a way that this compound is not returned to the second zone.

Abstract: Transition metal (0) or (1)/phosphine catalysts suited, e.g., for the hydrocyanation of ethylenically unsaturated compounds, are produced by reducing, via hydrogenation, aqueous solutions containing at least one transition metal compound and at least one monodentate or bidentate water-soluble phosphine, advantageously at least one phosphine having one of the following formulae (I) and/or (II):P(Ar1).sub.a (Ar2).sub.b (Ar3).sub.c (Q1).sub.d (Q2).sub.e (Q3).sub.f(I)(Ar1).sub.a (Ar2).sub.b (Ar3).sub.c (Q1).sub.d (Q2).sub.e P-L-P(Ar1).sub.g (Ar2).sub.h (Q1).sub.i (Q2).sub.j (II)In formulas (I) and (II), Ar1, Ar2 and Ar3 may be identical or different and are each an aryl radical or a substituted aryl radical. Q1, Q2 and Q3 may be identical or different and are each an alkyl radical, a cycloalkyl radical, a substituted alkyl radical, or a substituted cycloalkyl radical.

Abstract: A method for preparing carboxylic acids including (n+1) carbon atoms, or the related esters, by liquid phase carbonylation of an alcohol including (n) carbon atoms, in the presence of a uniform catalytic system based on at least one iridium compound and at least one halogenated promoter. In particular, the method is characterised in that the content of ester related to said carboxylic acid and alcohol is kept between 15 and 35% in the medium during the reaction, while the halogenated promoter content is kept between 10 and 20%, and the partial carbon monoxide pressure is 40-200 bar. Said method enables both the rate of carbonylation and the acetic acid selectivity to be increased.

Abstract: Catalyst compounds comprising at least one transition metal in an oxidation state of 0 to 1, and at least one monodentate or bidentate water-soluble phosphine, well suited for the hydrocyanation of ethylenically unsaturated compounds, are electrochemically synthesized, by electrolyzing an aqueous solution catholyte (contained in the cathode compartment of any suitable electrolytic cell) comprising at least one transition metal compound and at least one monodentate or bidentate water-soluble phosphine, advantageously at least one phosphine having the following formulae (I) and/or (II):P(Ar1).sub.a (Ar2).sub.b (Ar3).sub.c (D1).sub.d (D2).sub.e (D3).sub.f(I)(Ar1).sub.a (Ar2).sub.b (D1).sub.d (D2).sub.e P-L-P(Ar1).sub.g (Ar2).sub.h (D1).sub.i (D2).sub.j (II).

Abstract: The present invention relates to a process for the hydrocyanation of organic compounds containing ethylenic unsaturation to nitrites, in particular the hydrocyanation of diolefins or of substituted olefins, such as alkenenitriles.More specifically, it comprises a process for the hydrocyanation of organic compounds containing at least one ethylenic double bond by reaction with hydrogen cyanide in the presence of an aqueous solution of a catalyst comprising at least one transition metal compound and at least one water-soluble phosphine, characterized in that the said water-soluble phosphine is a monodentate or bidentate phosphine.

Abstract: Preparation of carboxylic acids or corresponding esters by reacting an alcohol with carbon monoxide in the presence of an iridium catalyst and a halogen promoter. The reaction involves a reaction mixture composed of more than 0% to 10% water, more than 0% to 10% halogen promoter, 2% to 40% of an ester corresponding to the reaction of alcohol with the acid, soluble iodides in an amount such that the atomic ratio of iodides to iridium varies between more than 0 and 10, the carboxylic acid being used as the reaction solvent.

Abstract: A method for preparing carboxylic acids by carbonylating a reagent, particularly an alcohol, in the presence of an iridium catalyst. According to the method, the liquid phase reaction is carried out in a first zone in the presence of an iridium catalyst, and the resulting reaction mixture is partially vaporised in a second zone. The vaporised fraction containing the carboxylic acid is later purified and the unvaporised liquid fraction containing the catalyst is recirculated to the first zone. The method is characterised in that said unvaporised fraction is contacted with carbon monoxide in such a way that this compound is not returned to the second zone.

Abstract: Pentenoic acids are selectively prepared via hydroxycarbonylation of butadiene with carbon monoxide and water, at a temperature above 30.degree. C., under a partial pressure of carbon monoxide, measured at 25.degree. C., equal to or greater than 0.5 bar, in the presence of a catalytically effective amount of an iridium-based catalyst and an iodine-containing or bromine-containing promoter therefor, in a solvent medium, wherein the iodine or bromine/iridium molar ratio is less than or equal to 20/1 and the concentration by weight of water in the reaction mixture is less than or equal to 8%.

Abstract: Catalyst compounds comprising at least one transition metal having an oxidation number of 0 or 1 and at least one sulfonated phosphine are electrochemically synthesized, by electrolyzing an aqueous solution catholyte (contained in the cathode compartment of any suitable electrolytic cell) comprising at least one transition metal compound and at least one sulfonated phosphine.

Abstract: Process for the preparation of a carboxylic acid or ester thereof. The process includes reacting at least one alcohol, alkyl or aryl halide, ether or ester, with carbon monoxide, in the presence of a catalytically effective amount of at least one rhodium compound or rhodium metal, at least one iridium compound or iridium metal, or at least one mixed rhodium/iridium compound, and at least one halogen-containing promoter therefor.

Abstract: Butadiene or derivative thereof is selectively hydroxycarbonylated into at least one pentenoic acid (the pentenoic acids are themselves facilely converted, via hydroxycarbonylation, into adipic acid, a basic starting material for the production of nylon 66 polymers), by reacting same with carbon monoxide and water, at a pressure greater than atmospheric, in the presence of a catalytically effective amount of (1) a palladium catalyst which is soluble in the medium of reaction and (2) crotyl chloride, the amount of the crotyl chloride being at least two mol thereof per mole of palladium values and said palladium values/crotyl chloride at least in part comprising a palladium/crotyl pi-complex, and the amount of water present in the medium of reaction being no greater than about 20% by weight thereof.

Abstract: At least a fraction of at least one branched, saturated aliphatic diacid having 6 carbon atoms, for example 2-methylglutaric acid and/or 2-ethylsuccinic acid and/or dimethylsuccinic acid, is separated from admixtures thereof with adipic acid, by at least partially converting such at least one aliphatic diacid into the corresponding anhydride thereof, and removing the corresponding anhydride or the adipic acid from the medium of conversion/anhydridization, for example by contemporaneous or subsequent distillation, or by crystallization.

Abstract: Ethylenically unsaturated aliphatic nitriles, for example the linear pentenenitriles, are converted/hydrocyanated into their corresponding dinitriles, for example adiponitrile, by reacting such nitriles with hydrogen cyanide, in an aqueous reaction medium which comprises (1) a catalytically effective amount of a transition metal compound and a sulfonated phosphine, together with (2) a cocatalytically effective amount of at least one Lewis acid; the Lewis acid cocatalyst promotes the linearity of the final product dinitriles and/or prolongs the useful life of the catalyst.

Abstract: 2-Methyl-3-butenenitrile is efficiently and readily converted into a linear pentenenitrile, notably 3-pentenenitrile, a valuable intermediate for the production of adiponitrile, by isomerizing same in the presence of a catalytically effective amount of an aqueous solution of at least one sulfonated phosphine and at least one transition metal compound.