Abstract: Amicrowave source with power 0-100 W,continuously adjustable,operating at a frequency of 2450 MHz and a surfatron discharge cavity was used for the experiment.The microwave-puncture curves of air and various alcohols(CH₃OH,C₂H₅OH,n-C₃H₇OH and i-C₃H₇OH)observed show that the lower-pressure vapor of alcohol was dissociated easier than air,resulting in plasma.The reactor effluent gases were analyzed by gas chromatography with FIdetector or TC-FI two-dimensional chromatography method on line.The electron temperature(T_e)of the alcohol plasma was identified using Langmuir double-probe.The results show that the products of plasma reaction were composed of H₂,H₂O,CO,CH₄,C₂H₄,C₂H₆,C₃H₆and C₃H₈, but C₂H₄was the main product.Not only the nature of the alcohol itself,but also the microwave power was responsible for the product abundance.This kind of reaction proceeded through a free radical mechanism,so the distribution and quantity of products show the species and quantity of free radicals in plasma.The yield of C₂H₄was increasing as the input-power increased,up to the maximum then followed by the decreasing,and the carbon deposit on the wall of reactor could be observed,which implied the deepdissociation took place in the case of higher power,and the higher hydrocarbon was not easily produced.

Key words: Microwave, Plasma chemistry, Lower alcohol