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.