GB622561A - Manufacture of di(alkoxyphenyl)haloethanes - Google Patents

Abstract

Di-(alkoxyphenyl) - haloethanes are prepared from an alkyl phenyl ether and a halogenated acetaldehyde in a homogeneous liquid reaction mixture in the presence of a condensing agent selected from aluminium chloride, bromide, or iodide, boron trifluoride, or hydrogen fluoride. Preferably, the alkyl group of the ether contains not more than 12 carbon atoms, e.g. it may be methyl, ethyl, propyl, isopropyl, butyl, or amyl, or the corresponding alkoxy groups. Suitable halogenated acetaldehydes are mono-, di- and trihaloacetaldehydes, e.g. bromal, and mono-, di- and tri-chloroacetaldehydes; the latter compound is preferred. A diluent may be used in the reaction, such as nitrobenzene, nitrotoluenes or ether, but it is preferred to use an excess of the ether constituent, i.e. 3 to 4 mols. of the ether to 1 mol. of the aldehyde. The aldehyde is added gradually with cooling to 30-60 DEG C. to a mixture of the ether and condensing agent, and at least 0.25 mols. (i.e. about 0.25-1 mol.) of the latter are used per 1 mol. of aldehyde. A preferred application of the invention is the reaction between chloral and anisole in the presence of aluminium chloride (0.4-0.6 mols.). In examples 2, 4, 7, 8, 9, 10, anisole and chloral are condensed under various conditions, in the presence of aluminium bromide and chloride, boron trifluoride and hydrogen fluoride as condensing agents, to give 2 : 2-bis-(41-methoxyphenyl)-1 : 1 : 1-tri-chloroethane; in example 3, chloral is replaced by dichloroacetaldehyde to give 2 : 2-bis-(41-methoxyphenyl)-1 : 1-dichloroethane; and in examples 1, 5 and 5, chloral is condensed in the presence of aluminium chloride with phenetole, dodecyl phenyl ether, and 1 : 4-dimethoxybenzene to give respectively 2 : 2-bis-(41-ethoxyphenyl)-, 2 : 2-bis-(41-dodecyloxyphenyl)- and 2 : 2-bis-(dimethoxyphenyl)-1 : 1 : 1-trichloro-ethane.