Improvements in the production of aryl derivatives of trihalogenoethane

摘要

Compounds having the general formula wherein R represents a phenyl residue substituted or not, and Z represents a halogen atom, are obtained by treating benzene, or a substitution derivative of benzene having at least one free position in the nucleus with an a : b : b : b -tetrahalogen ethyl ether in the presence of sulphuric acid or oleum as a condensing agent. Advantageously, an excess of benzene or benzene derivative is used. Specified R residues are: phenyl, phenyl substituted by, e.g. hydrocarbon, halogen including fluorine, and hydroxyl. In examples 1 to 4: to obtain a : a -(4-chlorophenyl)-b : b : b -tri-chloroethane, chlorobenzene is mixed with: (1) a : b : b : b -tetrachloroethyl ethyl ether in the presence of concentrated sulphuric acid; (2) a : b : b : b -tetrachloroethyl ethyl ether in the presence of (25 per cent SO3) oleum; (3) a : b : b : b -tetrachloroethyl methyl ether in the presence of (23 per cent SO3) oleum; (4) a : b : b : b -tetrachloro-ethyl n-butyl ether in the presence of (25 per cent SO3) oleum to obtain reaction mixtures which are worked up after being added to ice/ice water. In (5) a -chloro-b : b : b -tribromoethyl ethyl ether is treated with chlorobenzene in the presence of (23 per cent SO3) oleum to obtain a : a -bis-(4-chlorophenyl)-b : b : b -tribromo-ethane; (6) a : b : b : b -tetrachloro-ethyl ethyl ether is treated with benzene in the presence of concentrated sulphuric acid to obtain a : a -(bis-phenyl)-b : b : b -trichloroethane; in each example the reaction mixture is added to ice/ice water before being worked up. Specifications 547,871 and 547,874 are referred to. Samples furnished under Sect. 2 (5) relate to the preparation of (1) a : a -bis-(4-fluorophenyl)-b : b : b -trichloro-ethane by the treatment of a - chloro - b : b : b - tribromoethyl ether with chlorobenzene in the presence of concentrated sulphuric acid; (2) a : a -(bis-phenyl)-b : b : b -trichloro-ethane by the treatment of a : b : b : b -tetrachloroethyl ethyl ether with benzene in the presence of concentrated sulphuric acid; in each case the reaction mixture is added to ice/ice water before being worked up.