Reactions of ^34m,38Cl Recoil Atoms with Chloroethylenes

Abstract

The yield of 23% C 2 Cl 3 34m Cl measured in liquid C 2 Cl 4 is formed by direct hot replacement (5%) and via a 34m Cl addition/ CI elimination reaction sequence in an excited cage (18%). In the case of 1, 2-C 2 H 2 C1 2 2.6%ofthe 1, 2-C 2 H 2 tl 34m Cl yield is formed via a direct hot replacement reaction with retention of the original configuration and 13.3% by addition-elimination reactions with full racemisation. The addition of 34m Cl to 1,1-C 2 H 2 Cl 2 in a reaction cage proceeds mainly at the carbon atom of the CH 2 group. Replacement of H atoms can proceed via a direct hot reaction or via a cage reaction between a 34m Cl atom and a C 2 X 3 radical. The yield of high boiling compounds (about 44%) can be due to fragmentation/ addition reactions started by hot 34m Cl atoms, and partly by more thermal-like addition reactions of C 2 X s radicals. No satisfactory explanation could be given for the formation of inorganic yield of about 32%.

Reactions of radioactive recoil atoms with (halo) ethylenes

“…47 Brinkman et al proposed that an addition/elimination sequence in an excited cage results in a trans/cis ratio of 1.0 (their summed yield is 13%), whereas the remaining fraction (3%) is explained by a direct hot 34mCl-for-Cl substitution reaction. 52 In the elimination reaction there is a 1:1 possibility that the 34mCl atom is lost. If a new cycle is started, with a thermal 34mCl atom, more of the cis isomers can be expected, but, as will be discussed later, dimerization and further polymerization are another efficient reaction channel for liquid phase experiments.…”

“…Some of the data are given in Table VI. Product yields for the reactions of recoil 34mCl atoms with all the chloroethylenes (except C2H3C1) in the liquid phase are given in hardly changed on addition of a little I2). 52 Black and Morgan have performed similar experiments with recoil 38C1 atoms. 54 With the exception of CC12=CH2 the yields of products formed by similar reactions are almost equal for all the target compounds.…”