Metathesis of halogen-containing olefin over Re 2O 7/Al 2O 3 catalyst promoted with alkylmetal as a cocatalyst

Abstract

The 1-alkene containing bromide has been metathesized over Re 2O 7/Al 2O 3 catalyst promoted with alkylmetal as a cocatalyst to elucidate the effects of addition of alkylmetal and reaction conditions. The reaction was carried out using a continuous flow apparatus under atmospheric pressure. Various kinds of alkylmetal were employed as cocatalyst. By the addition of small amounts of tetraalkyltin, the activity increased greatly in the sequence of Bu-<Me-<Et-. The metal in alkylmetal also affected markedly the catalytic activity and the activity increased in the sequence of Si, Al≪Ge<Sn. The most favorable catalyst system was found to be Re 2O 7/Al 2O 3 catalyst promoted with SnEt 4 at 60°C. The metathesis of olefin having halogen ( ω-bromo- α-olefin) easily occurred under very mild reaction conditions such as 0°C and W/ F=6.1 g-cat·h/mol. The selectivity was always nearly 100% in spite of the differences in reaction conditions and kinds of cocatalyst. However, the catalytic activity decreased fairly faster compared to that of 1-hexene (1-C 6′). The deactivation mechanism will also be discussed.