The thermal decompositions of I-chloro-1-fluoroethane and 1-chloro-1,l-difluorethane at atmospheric pressure have been studied in the temperature range 500-6OO0C in a flow system. The dehydrochlorinations are homogenous in a carbonaceous reactor and unimolecular. The rate constants are given by The criteria for molecular or chain processes in thermal dehydrochlorinations are discussed.

The thermal decomposition of 1,2-dichloropropane at atmospheric pressure has been studied in the temperature range 227-59OoC, in a flow system. Above 45OoC, the reaction is homogenous and unimolecular with a rate constant:Below 45OoC, a low activation energy, probably heterogenous process competes with the gas phase reaction.The primary reaction products are HCl and the monochloropropene isomers; the relative amounts of each isomer depend on the temperature in the low but not in the high temperature region. The direction of the HCl elimination is discussed in terms of substituent effects at the a-and ,%carbon positions and compared with literature data on similar reactions.Secondary products are formed principally by further pyrolysis of ally1 chloride. The first-order rate constant of this reaction is given by: k = 10*.54*0.2 exp (-37,275 f 700/RT) sec-l.

The hydrogen abstraction from asymmetrically fluorinated and chlorofluorinated ethanes by chlorine atoms has been investigated in the gas phase between 264 and 333OK using the competition method. Arrhenius parameters for the reaction on both sites of the molecules are discussed.

The hydrogen abstraction from the chlorinated ethanes by chlorine atoms has been investigated in the liquid phase. Rate constants relative to that for hydrogen abstraction from chloroform have been measured between 2 6 7 O and 333OK using a competition technique. The results are compared with gas-phase data.

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