Rhodia Fiber & Resin Intermediates

Acetex Chimie

Rhone-poulenc Chimie

R. P. Fiber & Resin Intermediates

Rhone-poulenc Fiber & Resin Intermediates

Carl Patois

Robert M Perron

Daniel Marcel Thiebaut

Philippe Leconte

Eric B Henriet

Philippe Denis

Daniel Marchand

Lise Layeillon

Michel Spagnol

Francois Metz

Jacques Brivet

Phillipe Denis

A process for improving the stability and/or preventing the deactivation of catalyst in processes of continuous manufacture of acetic acid and/or methyl acetate includes a first, reaction step wherein at least one methyl formate isomerization reaction is carried out in a liquid phase reaction medium, in the presence of carbon monoxide and of a catalytic system including at least one halogenated promoter and at least one iridium-based catalytic compound, and, a second, flash step in which partial vaporization of a reaction medium originating from the first step is carried out in a flash separator. In a non-vaporized liquid fraction resulting from the partial vaporization in the flash separator, an overall content of formic acid and methyl formate is maintained at least equal to 1% by weight of said non-vaporized liquid fraction.

Process for improving the stability and/or preventing the deactivation of the catalyst during the manufacture of acetic acid and/or of methyl acetate

The present invention relates to process for improving the stability and/or preventing the deactivation of the catalyst in processes of manufacture of acetic acid and/or of methyl acetate according to which processes, in a first step, referred to as the reaction step, at least one methyl formate isomerization reaction is carried out in liquid phase, in the presence of carbon monoxide and of a catalytic system comprising at least one halogenated promoter and at least one iridium-based catalytic compound, and, in a second step, referred to as the flash step, the partial vaporization of the reaction medium originating from the first step is carried out in a separator referred to as the flash separator, characterized in that it consists in maintaining an overall content of formic acid and of methyl formate at least equal to 1% by weight of said liquid fraction, preferably between 1 and 50%, preferably between 1 and 30%, by weight with respect to said liquid fraction, in the non-vaporized liquid fraction originating from said flash separator. The invention also relates to a complete process of manufacture acetic acid and/or of methyl acetate which incorporates this improvement. The invention enables preparing acetic acid and/or methyl acetate with an increased stability of the catalytic system, even in the presence of contents of water which are particularly low, and of particularly low carbon monoxide pressures in the reaction zone, and is applied more particularly to processes of manufacture of acetic acid and/or of methyl acetate in which process the first step further comprises a methanol carbonylation reaction.

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&deg; 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.

Method for purifying adipic acid by crystallization

Method for preparing acetic acid and/or methyl acetate by isomerization and carbonylation

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.

Pentenoic acid hydroxycarbonylation method

Method for preparing acetic acid and/or methyl acetate by methyl formate isomerization

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.

Method for purifying adipic acid in water

The present invention concerns the aminomethylation of pentenoic acid derivatives, by reaction with carbon monoxide, hydrogen and ammonia, for preparing caprolactam. More precisely, it is directed to a method for preparing caprolactam wherein the aminomethylation of pentenoic acid derivatives is carried out by reaction with carbon monoxide, hydrogen, and ammonia, at a temperature higher than 30&deg; C. and in the presence of a catalyst with a base of at least one metal of Group VIII of the Periodic Table.

Preparation of caprolactam

The present invention relates to the isolation of a palladium-based catalyst from a mixture in which it is dissolved. More specifically, the invention relates to the isolation of a palladium-based catalyst from a mixture originating from the reaction of hydroxycarbonylation of butadiene to pentenoic acids. It therefore consists of a process for the isolation of at least a portion of the palladium dissolved in a solution also containing at least 3-pentenoic acid, characterized in that the said solution is acidified and stirred with an aqueous solution of hydrochloric acid, so as to obtain two liquid phases including an aqueous phase containing at least a portion of the palladium.

Process for isolation of a catalyst containing palladium

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%.

Preparation of pentenoic acids via hydroxycarbonylation of butadiene

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.

Hydroxycarbonylation of butadiene

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.

Separation of aliphatic diacids from adipic acid admixtures thereof

Unsaturated carboxylic acids, e.g., pentenoic acids, are prepared by carbonylating an allylic butenol and/or carboxylate ester thereof with carbon monoxide, in the presence of a catalytically effective amount of an iridium catalyst and an iodinated or brominated promoter therefor, and optionally, a copromoter, notably wherein the promoter/Ir molar ratio ranges from 0.1:1 to 20:1. The final product acids, e.g., 3-pentenoic acid, are themselves readily hydroxycarbonylated, for example, into adipic acid, via reaction with carbon monoxide and water.

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Riedisheim, France

Carl Patois