Sonophotocatalysis of Malonic Acid Solution: Possibility of a New Contribution to Organic Reactions

The synergistic effects of the combination of sonolysis and photocatalysis of malonic acid were examined. Not only increase in the reaction rate but also elongation of the carbon chain was observed. Firstly, the decomposition rate of malonic acid in the solution was improved; that is, the reaction rate for a combined system was higher than the sum of the rates of sonolysis and photocatalysis. Secondly, a small amount of succinic acid was detected; that is, the carbon numbers of dicarboxylic acid increased from C = 3 (malonic acid) to C = 4 (succinic acid) by sonophotocatalysis. It means the process of increasing molecular weight. We consider that this combined system will probably make a valuable contribution to organic reactions in the near future.