Liquid chromatography on carbosilochrom and carbosilica gel-silica adsorbents with a modified carbon surface

Abstract

The silica adsorbent Silochrom C-120 which is homogeneous, macroporous and thermally stable, and Spherisorb S20W which is a wide-pore silica gel have been modified by the deposition on them of carbon formed by the pyrolysis of benzene. The adsorbent structures before and after modification have been studied. Columns packed with the Carbosilochrom and Carbosilica gel so obtained were used for studies of their selectivity in the liquid chromatography of an homologous series of polymethyl-and monoalkylsubstituted benzenes, alkylnaphthalenes, methylphenols and benzoic esters on elution with solutions of methanol + water of different concentrations. An increase in the amount of carbon deposited on the adsorbent and an increase in solvent polarity results in an increase in adsorbent selectivity. In the case of polymethylsubstituted benzenes this increase is greater than in the case of isomeric monoalkylsubstituted benzenes. For phenols this increase is less than that for the corresponding hydrocarbons. The separating power of the column can be controlled by changing the degree of specificity of the carbosilica and the polarity of the eluent. © 1978 Friedr. Vieweg & Sohn Verlagschesellschaft mbH.