Hoechst Aktiengesellschaft

Klaus Schmitz

Klaus Gehrmann

Heinz Erpenbach

Hans-Klaus Kubbeler

Hans K Kubbeler

The invention relates to the production of anhydrous alkyl iodides. To this end, carboxylic acid alkyl esters of the formula R.sup.1 COOR.sup.2, in which R.sup.1 stands for hydrogen or an alkyl or aryl radical having from 1 to 8 carbon atoms and R.sup.2 stands for an alkyl group having from 1 to 4 carbon atoms, are reacted with iodine and hydrogen and optionally with carbon monoxide in the presence of compounds of noble metals comprised of rhodium, iridium, palladium or ruthenium as catalyst, and of a heterocyclic aromatic compound, in which at least one hetero atom is a quaternary nitrogen atom, or of a quaternary organophosphorus compound as a promoter, and optionally also in the presence of a carboxylic acid having from 1 to 8 carbon atoms and/or its anhydrides. The reaction is effected under practically anhydrous conditions at temperatures of from 350 to 420 K. and under a total pressure of up to 30 bars.

Process for making anhydrous alkyl iodides

The invention relates to an improved process for making acetic anhydride by reacting methyl acetate and/or dimethylether with carbon monoxide under practically anhydrous conditions, at temperatures of 350 to 575 K., under pressures of 1 to 300 bars, and in the presence of a catalyst system containing noble metals belonging to group VIII of the periodic system of the elements, or compounds thereof, iodine and/or its compounds, and an aliphatic carboxylic acid having 1 to 8 carbon atoms. The improved process is effected in the presence of a catalyst system containing, as additional ingredients, a heterocyclic aromatic compound, in which at least one hetero atom is a quaternary nitrogen atom, or a quaternary organophosphorus compound, and a zirconium compound being soluble in the reaction mixture.

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Erftstadt, Germany

Klaus Schmitz