Photolysis of methyl formate at 123.6nm

Abstract

Possible primary reaction channels for the dissociation of methyl formate were studied. The primary processes were found to be composed of a channel of molecular elimination and three channels of radical formation processes. In this study, the photolysis of methyl formate was performed at 123.6nm by using a Krypton resonance lamp over the pressure range of 1-40 Torr and at room temperature. Radical scavenger effect was also investigated by adding NO. The radical capture effect was observed by adding HBr as a radical capture. The major products were found to be CO, $CO_2$, $CH_4$, $C_2H_6$, $H_2CO$, and $CH_3OH$. From product analysis, the contributions of each primary processes were deduced by extrapolating the product quantum yields to low pressure limit where the chain processes could be neglected. The chain effect was observed by the pressure increase of parent molecule. The chain initiation mechanism was proposed and thought to be due to high translation energy hydrogen atom produced from dissociation of highly excited molecule or radical. Our finding of the reaction scheme was also found to be well agreement with the general trend that the molecular elimination process has enhanced with the photon energy and the radical formation process behaved opposite direction.