Abstract
A quantitative study of the sonolysis and the addition to olefins of bromotrichloromethane was performed. Under ultrasonic irradiation, bromotrichloromethane is cleaved to a bromine atom and a trichloromethyl radical (1) followed by the recombination to either bromotrichloromethane (2) or molecular bromine and hexachloroethane (3). Br-CCl_3 -)))→Br・ + ・CCL_3 (1) Br・+ -CCl_3 → Br-CCl_3 (2) 2・CCl_3 → Cl_3C-CCl_3 2Br・ → Br_2 (3) An addition of a small amount of n-octane to bromotrichloromethane decreased a yield of hexachloroethane. Since n-octane was added in the amount with little effect on the vapor pressure, the decrease in the yield of hexachloroethane is not due to the decrease in the sonolysis of BrCCl_3 but is due to the increase in the recombination (2). In the presence of 1-octene, BrCCl_3 gives the one-to-one addition product via the radical chain reaction with trichloromethyl radical (4) and (5). ・CCl_3 + C_6H_<13>-CH=CH_2 → C_6H_<13>-CH・-CH_2CCl_3 (4) C_6H_<13>-CH・-CH_2CCl_3 + Br-CCl_3 → C_6H_<13>-CHBr-CH_2CCl_3 + ・CCl_3 (5) When the mole fraction of the sum of n-octane and 1-octene was kept constant, the yield of bromotrichlorononane increased as increasing the concentration of 1-octene. The yields of hexachloroethane were almost constant in the presence of 1-octene, though the lower yield was obtained without 1-octene. Again, the change in mole ratio of n-octane to 1-octene does not affect the vapor pressure of the system. Therefore, the increased yield of hexachloroethane with 1-octene may be due to the suppression of the reaction (2) by 1-octene.
