| 摘要 |
HOE 88/H 006 Process for the preparation of monocarboxylic anhydrides of the disclosure In the process for the preparation of monocarboxylic anhydrides of the general formula (RCO)2O by reacting a carboxylic acid ester of dialkyl ether of the general formula RCOOR or ROR, where R in each case denotes the same alkyl radical having 1 to 4 carbon atoms, with carbon monoxide in the gas phase in the presence of iodine or bromine or compounds thereof as reaction promoter, and in the presence of a supported catalyst, at temperatures of from 130 to 400.degree.C and pressures of from 1 to 150 bar, where, in the supported catalyst, an organosilicon compound is bonded, as a polyfunctional coupling agent, on the one hand to a support material and on the other hand to a noble-metal compound from group VIII of the Periodic Table, a chelate-forming organosilicon compound of the general formula a) or b) is employed as the polyfunctional coupling agent, where X = Cl, Br or -OR2; Y = -NR?, a nitrogen-containing aryl radical, -PR?, AsR?, -SR4 or -SH; Z = zero, arylene or phenylene (optionally ortho-, metaor para-substituted), R1 = C1 to C5-alkyl; R2 = C1 to C5-alkyl or -C6H5; R3 = -H or C1 to C3-alkyl; R4 = C1 to C5-alkyl, C5 or C6-cycloalkyl or -C6H5 or -CH2C6H5, which are optionally substituted by halogen, methoxy, ethoxy or C1 to C3-alkyl groups; n = 0 or 1 or 2; m = 2 to 6, preferably 2 to 4. |
