| abstract |
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. |