Solvent Effects in Telomerization Reaction

Abstract

The effect of added solvents (aprotic and alicyclic, and hydroxylic fatty solvents) on the radical telomerization reaction of ethylene and carbon tetrachloride was investigated.
Among others, hydroxylic solvents, especially those possessing active hydrogen atoms contiguous to the hydroxyl group exerted a marked influence upon the telomerization initiated by azobisisobutyronitrile (AIBN), giving high yield of tetrachloroalkanes and considerable increase of the content of tetraehloropropane (1:1 adduct). However, the said effect of hydroxylic solvents was largely diminished in a monoethanolamine (MEA)-initiated telomerization reaction. Moreover, this solvent effect was also suppressed by addition of neutralizing agents for evolved hydrogen chloride and by application of high pressure of reaction and high concentration of AIBN (initiator).
Aprotic aromatic solvents showed retarding effect on the telomerization reaction to give low yield of tetrachloroalkanes. The said retarding effect was not observed for aprotic alicyclic solvents.
The composition of tetrachloroalkanes obtained in the presence of aprotic aromatic and alicyclic solvents was the same as in tert-butanol which possesses no active hydrogen atom adjacent to the OH-group.
By way of explanation, a radical reaction between carbon tetrachloride and hydroxylic solvent was assumed to give α-chloroalcohol with large chain-transferring capacity.