Hoechst Aktiengesellschaft

Klaus Gehrmann

Heinz Erpenbach

Alexander Ohorodnik

Winfried Lork

Peter Prinz

Stefan Schafer

Peter Horstermann

Hans-Klaus Kubbeler

Georg Kohl

Eberhard Auer

Elmar Lohmar

Johannes Rosenthal

Herbert Joest

Albert Mainski

Erhard Jagers

Paul Stutzke

Hermann Vierling

Wernfried Riechmann

Karl-Heinz Steil

Klaus Schmitz

Hubert Neumaier

Udo Dettmeier

Klaus Schmitt

Kurt Karrenbauer

Alfred Hauser

Gunter Legutke

George Kohl

Peter Zerres

Heinz-Josef Berns

Hans Klaus Kuebbeler

Friedhelm Bylsma

Peter Pring

Erpenbach Heinz

Hans K Kubbeler

To prepare acetic acid and acetic anhydride, methanol and methyl acetate are reacted under anhydrous conditions with carbon monoxide in the presence of a catalyst system containing carbonyl complexes of group VIII noble metals, methyl iodide, an alkali metal acetate or iodide, or quaternary organophosphonium or organoammonium acetate or iodide, The hot carbonylation mixture is decompressed, the evaporated components are fed to a first distillation zone, and the catalyst solution which remains is fed back to the reaction zone. In the first distillation zone, the volatile carbonylation products are subjected to fractional distillation; the low-boiling methyl iodide and methyl acetate pass back into the reaction zone, and the bottom product produced is a mixture of acetic acid and acetic anhydride, which is split into the pure components in a second distillation zone and a third distillation zone.

Process for the preparation of acetic acid and acetic anhydride

Iodine and its compounds are separated from the carbonylation products acetic acid, acetic anhydride or ethylidene diacetate obtained on subjecting dimethylether, methyl acetate or methanol to a carbonylation reaction in the presence of an iodine-containing catalyst. The quantity of total iodine contaminating the carbonylation products is reduced to less than 20 ppb iodine by treating the products at 20.degree.-200.degree. C. with peracetic acid, diacetyl peroxide or a compound yielding these two agents under the reaction conditions, and separating them distillatively.

Process for separating iodine and its compounds from the products

In order to prepare phenylalanine n-propyl ester hydrochloride, phenylalanine hydrochloride is reacted with n-propanol in the molar ration 1: (5 to 20) at temperatures from 80.degree. to 110.degree. C., preferably 85.degree. to 105.degree. C., at pressures from 0.1 to 1.5 bar in the presence of 0.1 to 0.75 mole of HCl/mole of phenylalanine hydrochloride as catalyst and in the presence of water entrainer, a concentration of water entrainer of 20 to 50% by weight being maintained in the reaction mixture.

Process for the preparation of phenylalanine n-propyl ester hydrochloride

In the process for the preparation of N-acetylphenylalanine by opening the ring of 2-methyl-4-benzylidene-1,3-oxazolin-5-one with water to give 2-acetaminocinnamic acid and subsequently catalytically hydrogenating the latter, both reaction stages are carried out in a mixture of an aliphatic C.sub.3 -ketone to C.sub.10 -ketone or a water-miscible ether and water as the solvent, and the hydrogenation of the 2-acetaminocinnamic acid is carried out at temperatures of 10.degree. to 50.degree. C. and pressures of 1 to 15 bar in the presence of a supported palladium catalyst.

Process for the preparation of n-acetylphenylalanine

Catalyst solution contaminated during the carbonylation of methyl acetate and/or dimethylether. To this end, the contaminated catalyst solution is subjected in a first processing stage to extraction with a dialkylether and alkanol, each of which has from 1-4 carbon atoms per alkyl group, and thereby freed from its organic contaminants, from acetic acid, acetic anhydride and ethylidene diacetate, and the ether phase is separated from the purified promoter-containing catalyst solution; next, the ether phase is treated in a second processing stage with iodine and/or methyl iodide; the precipitated promoter containing catalyst complex is separated and dissolved in the purified catalyst solution coming from the first processing stage; the ether phase is separated into its constituents by distilling it; recovered dialkylether and alkanol are used again in the extraction stage; fresh catalyst solution is prepared from the recovered mixture of acetic acid, acetic anhydride and ethylidene diacetate and from the united purified catalyst solution while residual dialkylether and alkanol are distilled off, and the organic contaminants retained in the residue of the ether phase distillation are expelled.

Process for purifying and recovering catalyst solution contaminated

A process for removing by product acetone from reaction mixtures obtained by reacting methyl acetate and/or dimethylether with carbon monoxide at elevated temperatures to obtain acetic anhydride in the presence of a catalyst system consisting essentially of carbonyl complexes of noble metals belonging to group VIII of the Periodic System of the elements, acetic acid, an organophosphorus or organonitrogen compound, and methyl iodide whereby the acetone obtained as a by-product during the reaction is subjected to condensation at temperatures of 50.degree. to 250.degree. C., under pressures of 0.01 to 150 bars and at a molar ratio as above defined for the catalyst system constituent of 1:(25-500):(10-100):(15-150) so as to obtain predominantly higher-boiling secondary products to be distillatively separated in a successive distillation zone together with volatile constituents of the catalyst system.

Process for removing acetone from reaction mixtures of carbonylation

The disclosure relates to a process for separating iodine and its compounds from the carbonlyation products acetic acid, acetic anhydride or ethylidene diacetate obtained by subjecting dimethylether, methyl acetate or methanol to a carbonylation reaction. For reducing the quantity of total iodine contaminating the carbonlyation products to less than 20 ppb iodine, the disclosure provides for the carbonylation products to be treated at temperatures of 20.degree. to 250.degree. C. with an alkyl or aryl phosphine or a heterocyclic aromatic nitrogen compound and at least one of the metals copper, silver, zinc or cadmium or their compounds and to be distillatively separated from the iodine thereby fixed in non-volatile form.

Process for separating iodine and its compounds from the carbonylation

Catalyst solution contaminated during the carbonylation of methyl acetate and/or dimethylether, containing carbonyl complexes of rhodium, quaternary heterocyclic aromatic nitrogen compounds or quaternary organophosphorus compounds as organic promoters, undistillable organic contaminants, acetic acid, acetic anhydride and ethylidene diacetate, is purified and recovered. To this end the contaminated catalyst solution is extracted with a dialkylether having from 1-4 carbon atoms and thereby freed from its organic contaminants, acetic acid, acetic anhydride and ethylidene diacetate, and the ether phase is separated from a precipitated promoter-containing catalyst complex; the ether phase is treated with iodine and/or methyl iodide, a further portion of precipitated promoter-containing catalyst complex is separated and united with the purified catalyst complex; the ether phase is distillatively separated into its constituents, recovered dialkylether is used for extraction, and fresh catalyst solution is prepared from the recovered mixture of acetic acid, acetic anhydride and ethylidene diacetate and united purified catalyst complex, and the organic contaminants retained in the residue coming from the ether phase distillation are expelled, and the purified catalyst is distillatively freed from residual dialkylether.

Process for purifying and recovering contaminated catalyst solution

The disclosure relates to a process for the continuous production of 2-carboxyethyl-alkyl-phosphinic acid dialkylesters by reacting an alkanephosphonous acid monoalkylester with an acrylic acid ester in the presence of a metal alcoholate. To this end, the disclosure provides:

Process for the continuous production of 2-carboxyethyl-alkyl-phosphinic

In this process for recovering noble metals of group VIII from a contaminated catalyst solution originating from the carbonylation of methyl acetate and/or dimethylether (the catalyst solution containing carbonyl complexes of these noble metals, organic or inorganic promoters, undistillable organic contaminants as well as volatiles) the volatiles are distillatively removed from the catalyst solution and the remaining distillation residue is water-treated, whereby the noble metal/carbonyl-complex is precipitated together with the organic contaminants and is separated from the aqueous phase, while the promotor is dissolved and recovered in conventional manner. The noble metals are then set free in elemental form by subjecting the noble metal/carbonyl-complex separated and contaminated with organic polymers at temperatures of 150.degree. to 300.degree. C. to treatment with an ethyleneglycoldialkylether solvent of the formula R(--OCH.sub.2 --CH.sub.2).sub.n --OR, in which n stands for a number of from 1 to 4 and R stands for identical or different alkyl groups having from 1 to 6 carbon atoms. The noble metal can then be recovered by filtration, and the solvent can be freed of organic contaminants by distillation.

Process for recovering noble metals belonging to group VIII of the

The disclosure relates to a process for purifying and recovering a contaminated catalyst solution which is obtained in the carbonylation of methyl acetate and/or dimethylether, the catalyst solution containing carbonyl complexes of noble metals of group VIII of the Periodic System of the elements, quaternary heterocyclic aromatic nitrogen compounds or quaternary organophosphorus compounds as organic promoters, and optionally compounds of carbonyl-yielding common metals as inorganic promoters, undistillable organic contaminants as well as acetic acid, acetic anhydride and ethylidene diacetate. To this end, the disclosure provides for the catalyst solution to be distillatively freed from its volatile constituents and for the remaining solid distillation residue to be freed from the organic contaminants by extraction with aliphatic ethers; and for the remaining undissolved mixture of noble metal/carbonyl-complex, organic and optionally inorganic promoters to be filtered off and recycled into the carbonylation reaction.

The disclosure relates to an improved process for making alkanephosphonous acid esters which comprises: introducing a stoichiometric excess each of an alkyldihalogenophosphane and aliphatic alcohol into a reaction column and reacting them therein at a temperature higher than the boiling point of the reactants but lower than the boiling point of the resulting alkanephosphonous acid ester, this latter being obtained in the base portion of the reaction column and being removed therefrom; continuously expelling overhead of the reaction column a vaporous mixture consisting of by-products formed during the reaction, in the form of hydrogen halide and halide of the aliphatic alcohol, together with aliphatic alcohol in excess, and separating the mixture into its components in a series-connected distilling column, the aliphatic alcohol obtained in the base portion of the distilling column being removed therefrom and recycled into the reaction column, and selectively condensing the mixture issuing overhead with recovery of hydrogen halide gas and liquefied halide of the aliphatic alcohol.

Process for making alkanephosphonous acid esters

The disclosure relates to a process for separating the catalyst system from reaction mixtures which are obtained by reacting methyl acetate and/or dimethylether with carbon monoxide and optionally hydrogen at elevated temperatures to acetic anhydride and optionally ethylidene diacetate in the presence of a catalyst system consisting of carbonyl complexes of noble metals belonging to group VIII of the Periodic System, acetic acid, an organophosphorus or organonitrogen compound, methyl iodide and optionally compounds of carbonyl-yielding common metals, and which issue from the reaction zone under a pressure of 25 to 150 bars at a temperature of 100.degree. to 250.degree. C. More particularly, the reaction mixture coming from the reaction zone is introduced into a separator heated to 60.degree. to 140.degree. C. and released to a pressure of 0.5 to 3.5 bars with spontaneous evaporation of the bulk of volatile constituents; the stream of liquid matter coming from the separator is delivered to a distilling zone and the bulk of still volatile constituents is distilled off therein under a pressure of 0.05 to 1 bar at a base temperature of 70.degree. to 170.degree. C.; and catalyst solution retained as base product is recycled to the reaction zone.

Process for separating the catalyst system from the reaction mixtures of

The disclosure relates to a process for making carboxylic acid halides by reacting an alkyl halide having 1 to 6 carbon atoms or aryl halide with carbon monoxide, optionally in admixture with up to 30 volume % hydrogen, under practically anhydrous conditions at temperatures of 350 to 575 K under pressures of 1 to 300 bars in the presence of a catalyst system containing at least one noble metal belonging to group VIII of the Periodic System of the elements or its compounds, iodine and/or its compounds and optionally an inert organic solvent. To this end, the disclosure provides for use to be made of a catalyst system which additionally contains a compound of the elements belonging to groups I to III of the Periodic System, and acetic acid.

Process for making carboxylic acid halides

The disclosure relates to a process for making methyldichlorophosphane by reacting methane with phosphorus trichloride in the presence of 2 to 7 mol % carbon tetrachloride, based on the phosphorus trichloride used, at temperatures of 500.degree. to 650.degree. C. and over a period of time of 0.1 to 0.9 second. More particularly, the reaction is effected under a pressure of 2 to 10 bars, the proportion of carbon tetrachloride added being reduced at increasing pressure.

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Erftstadt, Germany

Klaus Gehrmann