Patent ID: 7358385

Claim:
A process for preparing bicyclo[4.3.0]nonane-3(4),7(8)-dicarboxylic acid by hydroformylating bicyclo[4.3.0]nona-3,7-diene with subsequent oxidation, which comprises reacting bicyclo[4.3.0]nona-3,7-diene with synthesis gas in an homogeneous organic phase in the presence of transition metal compounds of Group VIII of the Periodic Table containing complex-bound organophosphorus compounds, and of excess organophosphorus compound, at temperatures of 70 to 160° C. and pressures of 5 to 35 MPa, and then oxidizing the resulting 3(4),7(8)-bisformylbicyclo[4.3.0]nonane to obtain bicyclo[4.3.0]nonane-3(4),7(8)-dicarboxylic acid.