Kinetics of thermal decomposition and of the reaction with oxygen, ethene and 1-octene of first generation Grubbs' catalyst precursor

摘要

The stability of the first generation Grubbs' catalyst precursor, [Ru(CHPh)Cl_2(PCy_3)_2], was investigated using thermal decomposition of the catalyst precursor. The reactivity towards O _2 as well as initiation of the catalyst precursor with ethene and 1-octene were also investigated. The thermal decomposition reaction was found to be a two reaction sequence with rate constants of 3.2(1) × 10 ~(-4) and 1.06(2) × 10~(-5) s~(-1) for the first and second reaction respectively at 53 °C. The reaction of [Ru(CHPh)Cl _2(PCy_3)_2] with O_2 was determined to be faster with a rate constant of 4.6(1) × 10~(-3) M~(-1) s~(-1) at 25 °C. It was found that the rate constants of decomposition of Grubbs' catalyst precursor and the reaction with O_2 are low compared to the rate constants of reaction with ethene and 1-octene, which were found to be 4.7(5) × 10~(-2) and 3.46(6) × 10~(-2) s~(-1) respectively at 25 °C.