PROCESS FOR STABILIZING CARBONYLATION CATALYST IN SOLUBLE FORM

ABSTRACT OF THE DISCLOSURE The present invention provides for an improved process wherein an olefin, an alcohol, or an ester, halide or ether derivative of said alcohol is reacted with car-bon monoxide in a liquid phase in the presence of a cata-lyst system that contains (a) a rhodium component, and (b) an iodine or bromine component. By passing at least a portion of the liquid reaction mass from the reaction zone to a separation zone of substantially lower CO partial pres-sure, at least a portion of the carbonylation products, as well as unreacted carbon monoxide, inert gases, and un-reacted olefin, alcohol, or alcohol derivative are vapor-ized and can be withdrawn from the separation zone. Pre-cipitation of the rhodium catalyst under carbon monoxide deficient conditions is prevented or retarded by addition to the system of a stabilizer which 1. is selected from N,N,N',N'-tetramethyl-o-phenylenediamine and 2,3'-dipyridyl, or 2. is a dibasic or polybasic carboxylic acid having the formula wherein Yl is of the ormula (CX1X2)m in which m is 2 to 10 and wherein Y2, Y3, Y4 and Y5 are of the formula (CX1X2)n in which n is 1 to 10, and X1 and X2 are inde-pendently selected from hydrogen, a halogen, lower alkyl, aryl, hydroxyl, carboxyl, amino, hydroxy-substituted alkyl and carboxy-substituted alkyl.