Synthesis of polysulfonates and polysulfonamides from 7,7‐dimethyl‐7H‐dibenzo[ c , h ]xanthene‐5,9‐disulfonyl chloride

Treatment of 7,7‐dimethyl‐7H‐dibenzo[ c,h ]xanthene with chlorosulfonic acid leads to the formation of the mono‐, di‐ and tetrasulfonyl chloride derivatives. The 5 and 9 positions of 7,7‐dimethyl‐7H‐dibenzo[ c,h ]xanthene were found to be most active toward electrophilic sulfonation. Polysufonates and polysulfonamides prepared from 7,7‐dimethyl‐7H‐dibenzo[ c,h ]xanthene‐5,9‐disulfonyl chloride exhibit glass transition temperatures above 200°C and show little weight loss at temperatures to 350°C.