hochbromierte derivatives of m - trifluormethyldiphenylaethers and procedures for their production

摘要

Derivs of formula (I): (where n is 7 or 8) are prepd. by brominating m-trifluoromethyl-diphenyl ether with excess Br2 in the presence of metallic iron or iron halides at 0-200 degrees C under normal or elevated press and sepg. the desired product from the reaction mixt. (I) have good thermal stability. (only slight discoloration occurs after prolonged heating at =300 degrees C) and are sol. in a wide range of conventional solvents. (I) are useful as heat-stable heat-transfer fluids, dielectrics, flameproofing agents for plastics and antural and synthetic fibres, insecticides, pesticides etc.