Process for the carbonylation of ethylenically unsaturated compounds

A process for the carbonylation of C3-C20 ethylenically unsaturated compounds which process comprises reacting said C3-C20 ethylenically unsaturated compound with carbon monoxide in the presence of a source of hydroxyl groups and of a catalyst system, the catalyst system obtainable by combining:

• (a) a metal of Group VIII or a compound thereof:
• and
• (b) a bidentate phosphine, stibine or arsine of general formula (I)
• wherein:
• Ar is a bridging group comprising an optionally substituted aryl moiety to which the phosphorus atoms are linked on available adjacent carbon atoms;
• A and B each independently represent lower alkylene;
• K, D, E and Z are substituents of the aryl moiety (Ar) and each independently represent hydrogen, lower alkyl, aryl, Het, halo, cyano, nitro, OR19, OC(O)R20, C(O)R21, C(O)OR22,
• NR23R24, C(O)NR25R26, C(S)R25R26, SR27, C(O)SR27, or -J-Q3(CR13(R14)(R15))CR16(R17)(R18) where J represents lower alkylene;
• or two adjacent groups selected from K, Z, D and E together with the carbon atoms of the aryl ring to which they are attached form a further phenyl ring, which is optionally substituted by one or more substituents selected from hydrogen, lower alkyl, halo, cyano, nitro, OR19, OC(O)R20, C(O)R21, C(O)OR22, NR23R24, C(O)NR25R26, C(S)R25R26, SR27, C(O)SR27;
• R1 to R18 each independently represent lower alkyl, aryl, or Het;
• R19 to R27 each independently represent hydrogen, lower alkyl, aryl or Het;
• each of Q1, Q2 and Q3 is independently selected from the group consisting of phosphorous, arsenic or antimony;
• wherein the carbonylation reaction is carried out at a temperature of between −30° C. to 49° C. and under a CO partial pressure of less than 30×105 N.m−2.