Laser Pyrolysis of CH₃Br

Abstract

Laser pyrolysis of CH3Br by a strong laser irradiation was studied in this work. Besides a fine needle of solid carbon was deposited at the surface on the substrate, HBr and CH4, were found as gaseous products with a ratio of 2:1. Small amount of C2H2 was also detected. The variation in the pressures of CH3Br, HBr and CH4 were measured by Raman spectroscopy. It indicated that the decomposition of CH3Br was first order with respect to CH3Br. The reaction mechanism of the laser pyrolysis was suggested as follows: After gaining enough energy at the hot spot, CHaBr was pyrolyzed to produce HBr and CH2 which then reacted with CH3Br to form CH4, and solid carbon.