GAMMA RADIOLYSIS OF ETHANOL VAPOR

The product yields changed only slightly as the temperature was increased from 60 to 200°. Increasing the ethanol pressure from 45 to 1700 torr at 150° decreased the yields of hydrogen, acetaldehyde, and ethylene but had no effect on those of methane and carbon monoxide. The changes of yield with pressure were interpreted in terms of excited molecules whose decomposition lifetimes had lower limits of 1.9 × 10−10 and 3.0 × 10−10 sec. The hydrogen and acetaldehyde yields decreased with increasing dose; this was attributed to the scavenging of electrons by acetaldehyde, with the ultimate formation of (CH3CHO−)·nC2H5OH. Propylene scavenges hydrogen atoms and other free radicals, but not ions or electrons in this system. The efficiency of scavenging methyl radicals increases with increasing pressure. Sulfur hexafluoride scavenges electrons; some of the resultant intermediates or products cause the yields of acetaldehyde and diethyl ether to increase. Direct formation of molecular hydrogen from ion-electron neutralization in ethanol vapor at 150° is negligible. Ammonia has no effect on the rates of formation of the ethanol radiolysis products because neutralization of either (C2H5OH)mH+ or (C2H5OH)mNH4+ by an electron results in the formation of a hydrogen atom, and the ultimate products are the same. © 1968, American Chemical Society. All rights reserved.