Toshikazu Hamamoto

Effects of Atmospheres, Solvents and Fatty Acids on Decomposition of Cyclohexanone Peroxide

Cyclohexanone peroxide (CYP) which was regarded as one of the intermediates of the autoxldation of cyclohexane was synthesized, and the effects of atmospheres, solvents and fatty acids on the decomposition were studied.The main decomposition product was cyclohexanone, and the decomposition rates were found to be proportional to the concentration of CYP(Figs.1 and 2).The rates of the decomposition, k, were dependent on atmospheres and solvents, i. e., the rate constant decreased in the order of nitrogeng carbon monoxideg carbon dioxideg heliumg hydrogeng airg oxygen and of acetic acid, cyclohexanoneg cyclohexanolg chlorobenzene, 1dodecanolg n-dodecaneg toluene, respectively(Table 1 and Figs.1 and 2). It should be noted that the yield of cyclohexanone was also dependenton the atmospheres.A linear relationship exists between log k and the values of (D-1)/(2D+1)(D: dielectric constants of solvents), except for n-dodecane and acetic acid(Fig.3). The activation energy for the decomposition in cyclohexanol at 80-120 C was calculated as 13.8kcal per mole(Fig.4).It was also found that the addition of the fatty acids caused the considerable acceleration of the decomposition and the rates were approximately proportional to the acidic strengths (Fig.5).The activation energy for the decomposition in n-dodecane containing 3.8 mol% propionic acid at 80-120 was calculated as 18.1kcal per mol.

Autoxidation of Cyclohexane and Decomposition of Cyclohexyl Hydroperoxide in the Presence of Metaboric Acid

The autoxidation of cyclohexane and the decomposition of cyclohexyl hydroperoxide (CHP), which was regarded as an intermediate of the autoxidation, were studied in the presence of metaboric acid and orthoboric acid ester in various solvents.It was found that the addition of the metaboric acid brought about considerable effects on the composition of the decomposition products, as well as an acceleration ef the decomposition of CHP (Table 1 and 2).The decompositlon rate of CHP in the presence of metaboric acid was of storde and of zero-order with respect to the concentration of CHP and the apparent concentration of metaboric acid, respectively.The rate constant k in the presence of metaboric acid in dodecane at 120-160C was as follows (Fig.2) k=3.31x10 11exp(-25.7x10 3/RT)min-1The decomposition rates of CHP in aromatic solvents were faster than those in paraflinic solvents (Fig.1). Ortheboric acid ester showed no catalytic activity in the decomposition of CHP (Table 2).Main products obtained by the decomposition of CHP in the presence of metaborie acid were cyclohexanol boric acid esters and small amount of cyclohexanone. Besides, alcohol boric acid esters and small amount of ketones, due to the oxidation of solvent, were also formed. A similar tendency was observed in the autoxidation of cyclohexane in the presence of metaboric acid (Table 3). It was considered that in the case of the autoxidation of cyclohexane in the presence of metaboric acid, cyelohexanol boric acid esters and active oxygen were formed by the reaction of CHP with metaboric acid.