Tritium recoil labeling of phenylacetic acid

Phenylacetia acid has been labeled by means of the nuclear reaction 6Li(n,α)3H, both in mixture with Li2CO3 and as the lithium salt. The amount of Li2 CO3 was such as to keep the same weight ratio of lithium and phenylacetate ion as in the salt. It was observed that intimate mixtures of phenylacetic acid and lithium carbonate react slowly indicating that previous studies on the irradiation of mixtures of organic acids with lithium carbonate have not been performed with well defined systems. A considerably higher specific activity of the acid was found in the case of the irradiation of the lithium salt. A series of degradative reactions which insures a double determination for the activity at each molecular position was applied. In contradiction with previous results, it was observed that considerable labeling takes place at the α‐position; somewhat less for the salt. The overall picture is one of uniform labeling in both cases, in agreement with the lack of selectivity shown by hot atom reactions.