1-3 a The letters A, B, C, etc., used in these columns stand for the aryl radical of the parent sulfonic acids shown in the first column. This was a comparatively crude phosphorus pentabromide prepared in carbon bisulfide; all the remaining experiments were carried out with pure phosphorus bromides or chlorides prepared in carbon tetrachloride. The yield depended to a large extent upon keeping the products thoroughly mixed and also on the ...
