KINETIC-STUDY OF THE DECOMPOSITION OF TERT-BUTYLHYDROPEROXIDE IN STYRENE, CATALYZED BY COBALT(II) AND COBALT(III) ACETYLACETONATES

As a result of studying the kinetics, products and volume yield of fre e radicals, a scheme is proposed for the mechanism of breakdown of ter t-butylhydroperoxide, catalysed by Co(II) and Co(III) acetylacetonates . The kinetic dependences correspond to a mechanism with the intermedi ate formation of a complex decomposing into products. The equilibrium constant K = 6.9 l/mole is not dependent on temperature and is the sam e for the two catalysts. The rate constants of decomposition of the ca talyst-hydroperoxide complex at 343-363 K are respectively k(Co(II)) = 1.05 x 10(14) (exp - 92 kJ . mole(-1)/RT) sec(-1) k(Co(III)) = 1.92 x 10(12) (exp - 92 kJ . mole(-1)/RT) sec(-1). The equality of constants K and of the activation energies of decomposition of intermediate com plexes for Co(II) and Co(III) with ROOH indicates that, irrespective o f the initial form of the catalyst in the two cases breakdown is carri ed out by the same intermediate catalytic form. The radical yield is 5 0%.