Analysis of products from breakdown of liquid benzene, toluene and cyclohexane caused by Nd 3+:YAG pulsed laser irradiation

Abstract

Products from liquid benzene, toluene and cyclohexane breakdown caused by strong Nd 3+:YAG fundamental pulsed laser irradiation were analyzed. Under nanosecond laser irradiation, hydrogen, methane, acetylene, ethylene, biphenyl, phenanthrene, anthracene and amorphous carbon were detected from liquid benzene and the laser intensity dependence of their yield was investigated. From laser intensity dependence of absolute quantity, it is suggested that biphenyl is produced by simple mechanism, while anthracene and phenanthrene are produced by diffusional collision of some kind of radicals via multi step reaction. In picosecond laser irradiation, the kind of products is same as those in nanosecond laser irradiation for liquid benzene, however yields of the products were higher because of stronger electric field. While in toluene and in cyclohexane same gaseous products as in benzene were detected. In particular, ethane was detected only from cyclohexane. In ultrasonic irradiation that is known as high pressure and high temperature reaction into liquid benzene and liquid toluene, results were different from those of laser irradiation. We could conclude that the reaction caused by near-infrared laser-induced breakdown is basically different from the reaction induced by high pressure and high temperature.