Hoechst Aktiengesellschaft

Heinz Erpenbach

Klaus Gehrmann

Winfried Lork

Peter Prinz

Erhard Jagers

Georg Kohl

Hans-Klaus Kubbeler

Peter Horstermann

Herbert Joest

Norbert Weferling

Reinhard Gradl

Andreas Seidel

Klaus Schmitz

Bernhard Kuxdorf

Eitel Goedicke

Manfred Bohshar

Heribert Tetzlaff

Klaus Schmitt

Hanss-Jerg Kleiner

Kurt Karrenbauer

Alfred Hauser

Wernfried Riechmann

Klaus Gunther

Herbert Pusche

Gerog Kohl

Hans Klaus Kuebbeler

Hans-Peter Koll

Peter Zerres

Peter Pring

Hans K Kubbeler

George Kohl

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

A process for continuously producing an anhydrous methyl acetate/methanol mixture by esterifying acetic acid and methanol in the presence of an acidic esterification catalyst is indicated, which comprises carrying out the esterification in a distillation column having n=20 to 50 distillation trays,

Process for continuously producing an anhydrous methyl acetate/methanol

A process for inhibiting and destroying peroxides in dialkyl ethers having the general formula R.sub.1 OR.sub.2 in which R.sub.1 and R.sub.2 are alkyl groups having 1 to 6 carbon atoms, which comprises adding, as inhibitor, a quaternary alkyl iodide of the general formula

Process for inhibiting and destroying peroxides in dialkyl ethers

A process for removing metallic corrosion products from carbonylation reactions which are carried out under anhydrous conditions and in which methyl acetate and/or methanol and/or dimethyl ether are reacted over a noble metal catalyst system which comprises a noble metal of group VIII of the periodic table of the elements, a co-catalyst, such as iodide or bromide, in particular methyl iodide, and a promoter, such as an organophosphonium or organoammonium salt, and if appropriate a lithium salt, to give acetic acid and/or acetic anhydride is described, the process comprising

Process for removing metallic corrosion products from carbonylation

In order to prepare N-acylphosphinothricin diesters, acetals of methyl-(3-oxopropyl)phosphinic acid esters of the formula ##STR1## are reacted in a dipolar aprotic solvent with a carboxylic acid amide and carbon monoxide in the presence of hydrogen gas using a cobalt compound as a catalyst, where the radical R' is alkyl or aryl or aralkyl.

Process for the preparation of N-acylphosphinothricin diesters

In a process for the purification and recovery of a contaminated catalyst solution produced during carbonylation of methanol and/or methyl acetate and/or dimethyl ether and containing carbonyl complexes of rhodium, organic and/or inorganic promoters, undistillable organic impurities and acetic acid, acetic anhydride and ethylidene diacetate, the organic impurities and acetic acid, acetic anhydride and ethylidene diacetate are removed from the contaminatd catalyst solution by extraction at pressures from 35 to 450 bar and temperatures from 0.degree. to 120.degree. C. with a liquefied or supercritical gas, and the phase of the liquefied or supercritical gas is separated from the purified, promoter-containing catalyst solution, the phase of the liquefied or supercritical gas is separated by flash vaporization, the recovered gas is re-employed for extraction, acetic acid, acetic anhydride and ethylidene diacetate are separated off from the component which remains liquid, and are combined with the purified catalyst complex to prepare fresh catalyst solution and, finally, the organic impurities remaining as the residue on separation of the phase of the liquefied or supercritical gas is purged.

Process for the purification and recovery of the contaminated solution

A process for purifying and recovering the contaminated catalyst solution arising from the carbonylation of methanol, methyl acetate and/or dimethyl ether. The solution contains carbonyl complexes of rhodium, quaternary organophosphorus compounds as organic promoters, undistillable organic impurities, and acetic acid, acetic anhydride and ethylidene diacetate. The carbonyl complex of rhodium together with acetic acid, acetic anhydride and ethylidene diacetate are extracted from the contaminated catalyst solution by using a tri-C.sub.3 - to C.sub.8 -alkylphosphine. The trialkylphosphine phase is separated from the promoter phase and is separated into the volatile constituents acetic acid, acetic anhydride and ethylidene diacetate as well as trialkylphosphine. The rhodium carbonyl complex remaining as the residue and the recovered trialkylphosphine is used for further extraction. The contaminated promoter phase is freed of the organic impurities by extraction with dialkyl ethers, carboxylic acid esters or hydrocarbons and, after the extractant phase has been separated off, is recombined with the recovered acetic acid/acetic anhydride and ethylidene diacetate mixture and with the rhodium carbonyl complex and recycled to the carbonylation reactor. The impurities remaining as the residue from a distillation of the extractant phase which has been separated off are removed from the system.

Process for purifying and recovering the contaminated catalyst solution

In a process for removing the metallic corrosion products from a contaminated catalyst solution produced on carbonylation of methanol and/or methyl acetate and/or dimethyl ether and containing carbonyl complexes of noble metals from group VIII of the Periodic Table of the elements, quaternary organo-phosphorus compounds as organic promoters, metallic corrosion products and acetic acid, acetic anhydride, ethylidene diacetate and, in some cases, undistillable organic compounds, the catalyst solution is treated with water, the noble metal carbonyl complex and the undistillable organic compounds, if present, being precipitated, while the organic promoter and the metallic corrosion products remain in solution; the aqueous phase is separated from the precipitated noble metal carbonyl complex and the organic promoter is extracted from the aqueous phase using C.sub.4 -C.sub.8 -alkanols, the promoter is recovered by evaporating the extractant, the promoter is recombined with the precipitated nobel metal carbonyl complex and with the undistillable organic compounds, if present, and the purified catalyst solution is recycled into the process after addition of acetic acid and/or acetic anhydride; finally, the aqueous phase with the metallic corrosion products is purged.

Process for removing metallic corrosion products from a contaminated

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

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.

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Cologne, Germany

Heinz Erpenbach