4,4'-disubstituted diphenyl ethers prodn - by reacting para-substd halo-or nitrophenyl cpds with alkali metal nitrite

摘要

Title cpds. are prepd. by reacting p-substd. halo-or nitro-phenyl cpds. with an alkali metal nitrite pref. sodium nitrite, at a mole ratio of 1 : 1-4.5 in a polar organic solvent at 100-220 degrees C. 4,4'-Disubstd. diphenyl ethers contng. substituents which are sensitive to hydrolysis e.g. 4,4'-dicyanodiphenyl ether, can be prepd. with the present process. 4,4'-Dicyanodiphenyl ether is used for prodn. of thermally stable polybenzimidazoles.