GB975111A - Dielectric compositions comprising substituted benzoic esters - Google Patents

Abstract

Compounds having a dielectric constant of at least 8 and represented by the formula <FORM:0975111/C1/1> wherein X is acetyl, propionyl, bromine, chlorine, fluorine, benzoyl or substituted benzoyl in which the substituent is methyl, chlorine, bromine or fluorine and R is an alkyl radical having 1-10 carbon atoms, a cycloalkyl radical, a benzyl radical having a single aromatic ring or a polyfluoroalkyl group having the formula -CH2 (CF2)nY where Y is hydrogen or fluorine and n is 1-5 including the pseudo form of the compound when X is acyl or aroyl, for use in dielectric compositions (see Division H1), are prepared by conventional methods for esterification of alcohols with acids in the presence of sulphuric acid or hydrogen chloride or by converting appropriate o-substituted benzoic acids to the corresponding acid chlorides with thionyl chloride or phosphorus pentachloride and reacting the acid chloride obtained with an appropriate alcohol. The products may exist in normal and pseudo forms e.g. <FORM:0975111/C1/2> and <FORM:0975111/C1/3> Many compounds having the first general formula given above are listed. The preparation is described of propyl o-benzoyl benzoate in normal and mixed normal and pseudo forms, benzyl o-benzoyl benzoate in normal form, propyl o-acetylbenzoate in mixed normal and pseudo forms, a tetrafluoropropyl o-benzoyl benzoate almost wholly in normal form, a trifluoromethyl o-benzoyl benzoate in pseudo form, an octafluoropentyl o-benzoyl benzoate, a tetrafluoropropyl o-acetylbenzoate almost wholly in pseudo form and tetrafluoropropyl o-chloro- and -o-fluorobenzoates.