The thermolysis of gaseous solutions of acrolein in the 500-600" region yields principally carbon monoxide, ethylene. propylene, hydrogen, methane, ethane, 1,3-butadiene and 1-butene in decreasing order of importance. The results are rationalized in part by a short chain decomposition of the aldehyde through vinyl radicals for which the unstable acrylyl fragment is a precuisor. Studies of the methyl radical induced decomposition of acrolein at 250" in the gas phase and the f-butyl hypochlorite photochlorination of the aldehyde a t 22" in solution allow rough approximations of kaddltlan/kabbtraction for methyl and t-butoxy free radicals to be made. These estimates are 4 and (max.), respectively.OXAR 51:. STEWAKI) . I XD OGDEN R. PIERCE Vol. 83 glycol column resolved carbon tetrachloride, t-butyl alcohol and t-butyl acrylate from a mixture of acrolein and acetone. The acrolein-acetone pair was resolved on P,B'-oxydipropionitrile. The blip corresponding to t-butyl acrylate was trapped ten times from the triethylene glycol column. Its infrared spectrum was identical with the spectrum of authen-A&nowledgment.-The authors are indebted to >/lr, F. L. ~~d~~~~ for patient assistance with the experimentation.128) This substance was prepared in poor yield from acrylyl chloride and l-butyl alcohol in t h e presence of P\TazCOj; b.p. 56' (80 m m . ) ,The first-order rate constaiits for the acid-catalyzed hydrolysis of sixteen fluoroalkyl-, w-cyanoalkyl-and n-alkylsiliconThe first-The correlations are discussed in terms of polar effects, hydrides have been determined using aqueous ethanolic hydrochloric acid (1.43 N , 95 v o l . -~, ethanol) a t 34.8". order rate constants are correlated using the Taft equation. steric effects and dative r-bonding.