摘要 |
A method for making a diester of oxalic acid which comprises oxidatively carbonylating an alcohol having 1 to 10 carbon atoms with carbon monoxide and with oxygen at a pressure from 1 to 700 bars and at a temperature from 20 DEG C. to 250 DEG C. in a reaction phase comprising said alcohol having dissolved therein a catalyst system consisting essentially of, as cations, ions of palladium(II) and copper ions in a molar ratio of at least 0.2 and, as anions, halide ions and carboxylate ions having 1 to 6 carbon atoms, the amounts of all ions in said catalyst system being such that the solution of the cations and anions in the alcohol has a formal pH value, as determined electrometrically, between 8 and 5. |