Studies in chain transfer. V. Acrylonitrile

Abstract

Chain-transfer coefficients (C_s) with twenty-six different solvents at 60°C for acrylonitrile (M) have been measured by catalyzed polymerization studies using azobisisobutyronitrile (I) as catalyst ([I]/[M]=6.1×10^-4 mol/l.). For non-halogenated solvents the C_s values are found to be generally higher by an order than those of styrene, but the relative trend is more or less similar in both cases. The transfer characteristics of acrylonitrile with halogenated solvents are, however, in striking contrast with those of all other monomers so far studied. The halogenated solvents such as CCl₄ which are usually extremely high chain-transferring agents are found to be devoid of any special susceptibility to an attack by the free radical of acrylonitrile. It is suggested that the inherent instability of compounds containing the group of >C(Cl)CN is responsible for the above unusual behaviour. The C_M and δ(= k_t^½/k_p) for acrylonitrile (60°C) have also been determined and are 2.6×10^-5 and 2.8 respectively.