Binary and Ternary Catalytic Systems for Olefin Metathesis Based on MoCl5/SiO2

Kinetics of alpha-olefin metathesis in the presence of binary (MoCl(5)/SiO(2)-Me4Sn) and ternary catalytic systems (MoCl(5)/SiO(2)-Me(4)Sn-ECl(4), E = Si or Ge) was studied. Specifically, kinetics and reactivity of 1-decene, 1-octene, and 1-hexene in the metathesis reaction at 27 degrees C and 50 degrees C in the presence of MoCl(5)/SiO(2)-SnMe(4) were examined and evaluated in detail. It was shown that experimental data comply well with the simple kinetic equation for the rate of formation of symmetrical olefins with allowance for the reverse reaction and catalyst deactivation: r = (k(1) . c(alpha) - k(-1) . c(s)). e(-kd.(n) over tilde tot). The coefficients for this equation were determined, and it was shown that these alpha-olefins had practically the same reactivity. It was found that reactivation in the course of metathesis took place due to the addition of a third component (silicon tetrachloride or germanium tetrachloride in combination with tetramethyltin) to a partially deactivated catalyst. The number of active centers was determined (5-6% of the amount of Mo) and the mechanisms of formation, deactivation, and reactivation were proposed for the binary and ternary catalytic systems. The role of individual components of the catalytic systems was revealed.