Hoechst Aktiengesellschaft

Peter Prinz

Heinz Erpenbach

Winfried Lork

Klaus Gehrmann

Andreas Seidel

Norbert Weferling

Reinhard Gradl

Erhard Jagers

Alfred Hauser

A process for the removal of aldehydes and acetals from industrially prepared acetic acid, wherein the contaminated acetic acid is reacted in the presence of a Bronstedt acid and 0.05 to 1% by weight of water and, if required, of 3 to 10 equivalents, calculated on aldehyde and acetal, of a high boiling polyhydric alcohol, and isolating the purified acetic acid by fractional distillation.

Process for the removal of aldehydes and acetals from industrially

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

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

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.

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 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 separating acetone from reaction mixtures originating from the reaction of methyl acetate and/or dimethylether with carbon monoxide and optionally hydrogen in the presence of a catalyst system consisting of carbonyl complexes of noble metals of group VIII of the Periodic System of the elements, acetic acid, an organophosphorus or organonitrogen compound, methyl iodide and optionally carbonyl-yielding compounds of common metals. To this end, the disclosure provides for the reaction mixture containing acetic anhydride, acetic acid, ethylidene diacetate, methyl iodide, acetone and methyl acetate which is distilled off from the catalyst solution, or just its low boiler fraction consisting of methyl acetate, methyl iodide and acetone to be subjected wholly or partially to an extractive distillation with acetic acid and for pure methyl iodide to be distilled off; for an acetone/methyl acetate mixture to be distilled off from the acetic acid extract; for this mixture to be separated in known fashion and for the acetic acid extractant to be recycled into the extraction stage, if desired after separation of the final reaction products comprised of acetic anhydride; ethylidene diacetate and acetic acid.

Process for separating acetone from carbonylation mixtures

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, 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 water-treated, the noble metal/carbonyl-complex being precipitated together with the organic contaminants and the organic promoter becoming dissolved; for the precipitated and contaminated noble metal/carbonyl-complex to be removed by filtration and to be freed from the organic contaminants by extraction with aliphatic ethers; for the organic promoter to be recovered by evaporating the water or extracting it with halogenated hydrocarbons and for these latter to be evaporated; and for the purified noble metal/carbonyl-complex and the recovered organic promoter to be recycled into the carbonylation reaction.

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, 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 water-treated, the noble metal/carbonyl-complex being precipitated together with the organic contaminants and the organic promoter becoming dissolved; for the precipitated and contaminated noble metal/carbonyl-complex to be removed by filtration and for the noble metal to be recovered terefrom in known fashion; for the organic promoter to be recovered by evaporating the water or extracting it with halogenated hydrocarbons and for these latter to be evaporated.

The invention relates to the manufacture of carboxylic acid halides. To this end, an alkyl halide having from 1 to 6 carbon atoms or an aryl halide is reacted with carbon monoxide under practically anhydrous conditions at temperatures of 350 to 575 K. and under pressures of 1 to 300 bars in the presence of a catalyst system containing at least one of the noble metals selected from rhodium, palladium, iridium or their compounds, iodine and/or its compounds, methyl trialkyl phosphonium iodide and/or methyl triaryl phosphonium iodide, and optionally trialkyl phosphine oxide or triaryl phosphine oxide as well as an inert organic solvent. More specifically, the reaction mixture is admixed with 0.02 to 0.75 mol of hydrogen per mol of carbon monoxide.

Production of acrylic acid by reacting acrolein with molecular oxygen in the presence of steam and, if desired, inert gases at elevated temperature in contact with a fixed bed of cobalt molybdate catalyst prepared by precipitating cobalt molybdate from the combined aqueous solutions of a cobalt salt, of a molybdenum compound and of ammonia at a temperature of about 60.degree.C and at a pH of at most 7; filtering off, washing and drying the precipitate at a temperature of at least 100.degree.C; heating the dry cobalt molybdate for several hours at elevated temperatures, grinding and transforming it into shapes; and sintering the cobalt molybdate shapes for several hours. The acrylic acid is more particularly produced in contact with a catalyst prepared by combining the aqueous solution of the cobalt salt with that of the molybdenum compound in the atomic ratio of Co:Mo of about 1.05:1; establishing in the combined solutions a pH between 3.8 and 6.0; drying the precipitate at 110.degree.-170.degree.C; heating the dry cobalt molybdate to temperatures between 250.degree. and 550.degree.C; and sintering the cobalt molybdate shapes at temperatures between 500.degree. and 700.degree.C so as to obtain a cobalt molybdate catalyst having an inner surface area between 4 and 8 square meters/g and a volume of pores between 0.1 and 0.2 milliliters/g.

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Hurth, Germany

Peter Prinz