间位(m-)氯代苯甲酸是某些化学工业的重要原料,但往往含有对位(p-)和邻位(o-)异构体。由于p、m异构体的极性差别较小且沸点接近,用常规固定液,气相色谱法不能分离氯代苯甲酸甲酯异构体。据文献报道,用适于分离位置异构体的液晶作固定液,只能分离p、m异构体,而不能分离p、o Meta (m-) Chlorobenzoic acid is an important starting material for some chemical industries, but often contains para (p-) and ortho- (o-) isomers. Due to the small differences in the polarity of the p, m isomers and the close proximity of the boiling points, the methyl chloroformate isomers can not be separated by gas chromatography using conventional fixatives. It has been reported in the literature that a liquid crystal suitable for the separation of positional isomers can only be used to separate p and m isomers but not p and o