摘要 |
Carbamic acid fluorides or isocyanates substituted with fluorine on aliphatic carbon atoms are prepared by reacting anhydrous hydrogen fluoride with an isocyanate which has chlorine substituents on aliphatic carbon atoms. Examples prepare (1) p-trifluoromethylphenyl isocyanate and p-difluorochloromethylphenyl isocyanate from p-trichloromethylphenyl isocyanate; (2) o-difluoromethylphenyl isocyanate and o-fluorochloromethylphenyl isocyanate from o-isocyanatobenzol chloride; (3) 2-trifluoromethyl -4-chlorophenyl carbamic acid fluoride from 2-trichloromethyl -4- chlorophenyl isocyanate; (4) 2,4-bis-(trifluoromethyl)-phenyl carbamic acid fluoride from 2, 4-bis-(trichloromethyl)-phenyl isocyanate; (5) 2-trifluoromethyl -4- chlorobenzene-1, 5-diisocyanate as the mono-carbamic acid fluoride from 2-trichloromethyl -4- chlorobenzene-1, 5-diisocyanate (obtained by chlorination of toluene-2, 4-diisocyanate); (6) 1, 3-bis-(trifluoromethyl)-benzene-4, 6-bis-carbamyl fluoride from 1, 3-bis-(trichloromethyl)-benzene-4, 6-diisocyanate; and (7) a fluorinated isocyanate from tetrachloroethyl isocyanate. Other starting materials are listed. Specification 916,275 is referred to. |