Very recently, we discovered that when cyclopropyl radicals are added to vinylidene fluoride, the regioselectivity of the addition is probably affected by a genometry factor of the solvent molecules. On the other hand, literature reports on the chemical behavior of the precursor of the cyclopropyl radicals, bis (cyclopropylformyl) peroxide (1) in various solvents are not consistent with each other. Therefore we decided to investigate the chemical behavior of the peroxide 1 in various solvents in more detail. Firstly, a procedure to measure quantitatively the five major products, viz., cyclopropyl cyclopropanecarboxylate (4), cyclopropylcarboxylic acid (5), bicyclopropane (6), cyclopropane (7) and carbon dioxide, was worked out, then the variations of the yields of each product from the decomposition of 1 were determined in seven different solvents. Our results indicate that in non-polar hydrocarbon solvents the main reaction is the unimolecular decomposition of 1, and in polar solvents there is also an induced decomposition. the observation that most of products 4, 6 and 7 are formed outside of the cage disaccords with literature reports. More interestingly, we discovered that the decomposition of 1 in HMPA might proceed via an electron transfer machanism involving the solvent molecules as donors.

Key words: REACTION MECHANISM, CYCLOPROPANE CARBOXYLIC ACID P, THERMOLYSIS, PEROXIDE