Hexyl radicals distribution

The alkyl radicals disappear by combination and disproportionation, but considerable confusion exists as to their basic yield. From experiments with scavengers results a value of about 2 for the G-value of primary formed hexyl radicals (22, 34) the disproportionation/combination ratio of hexyl radicals has been determined as 0.7 (I). These two values are, however, not compatible with the measured product distribution as a function of temperature (7). 

The hexenes form besides hydrogen the largest product group in the radiolysis of the paraffins. They can be formed by Reaction 1 and by disproportionation of hexyl radicals. The decrease of their G-value on deuteration is 1.5, the corresponding decrease of G( molecular hydrogen) is 1.6. This is additional proof for an isotope effect for Reaction 1. This reaction explains also the observation that the isomeric distribution of... 

Fig. 2.1. Schematic illustration of polyethylene molecular structure of various density ranges (Elias 1992). Top LDPE, radical polymerisation yields a number of (long) side ehains. Bottom HDPE, catalytic polymerisation gives rise to linear ehains with a small number of short branches. Both drawings in the middle illustrate LLDPEs produced by catalytic polymerisation with a-olefines. Small amounts of bntene-1, hexene-1 or octene-1 co-monomers lead to etlyl, butyl or hexyl side chains. Polymerisation in the gaseous phase produces chains arranged in a block-shaped fashion and distributed at various frequencies along the chaia Solution phase polymerisation provides a statistical random distribution along the whole chain...

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