New bidentate ligands, catalyst comprising such bidentate ligandsand process for the carbonylation of ethylencally or acetylenically unsaturated compounds using such a catalyst

摘要

Bidentate ligand of formula (I), R¹R²M¹-R-M²R³R⁴ wherein M¹ and M² each indenpendently represent P, As or Sb; R¹, R², R³ and R⁴ each independently represent the same or a different optionally substituted organic group and at least one of R¹, R², R³ and R⁴ contains a tertiary carbon atom through which the group is linked to M¹ or M²; and R represents a bridging group based on a trimethylene group connecting M¹ and M² of which the middle carbon atom is double bonded to a non-metal element chosen from group 14, 15 or 16 of the periodic table of elements. Catalyst comprising this bidentate ligand and carbonylation process n which this catalyst is used.