The 80 : p-ratio for the bromination of biphenyl by hypobromous acid in 75% acetic acid has been found to depend markedly on the concentration of mineral acid, being 0.17 without acid, and reaching a limiting value, 0.59, in the presence of 0.2~-perchloric acid. These results and those of kinetic measurements suggest that the effective electrophile is a form of positive bromine when mineral acid is added, but that in the absence of mineral acid the neutral species, bromine acetate, is concerned. The partial rate factors for para-substitution in biphenyl a t 1' are estimated to be about 38 for the cation and about 3000 for the neutral molecule.
Summary
The emulsion polymerization at 40°C. of mixtures of oxidized ethyl linoleate and styrene with potassium persulfate as catalyst yielded copolymers containing a maximum of one mole of ester per thirteen moles of styrene. A product of similar composition was obtained by bulk polymerization at 80°C.
When the amount of ester in the monomer mixture was increased to 50 per cent in the emulsion polymerization, the ester content of the polymer was increased and the molecular weight and yield were decreased.
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