Autocatalytic behavior of trimethylindium during thermal decomposition

Pyrolysis of trimethylindium (TMIn) in a hot-wall flow-tube reactor has bee n investigated at temperatures between 573 and 723 K using a modulated mole cular-beam mass-sampling technique and detailed numerical modeling. The TMI n was exposed to various mixtures of carrier gases: He, H-2, D-2, and C2H4, in an effort to elucidate the behavior exhibited by this compound in diffe rent chemical environments. The decomposition of TMIn is a heterogeneous, a utocatalytic process with an induction period that is carrier-gas dependent and lasts on the order of minutes. After activation of the tube wall, the thermolysis exhibits a steady-state behavior that is surface mediated. This result is contrary to prior literature reports, which state that decomposi tion occurs in the gas phase via successive loss of the CH3 ligands. This f inding also suggests that the bond dissociation energy for the (CH3)(2)In-C H3 bond derived from flow-tube investigations is erroneous and should be re evaluated.