Acylation of Aminopropyl-Bonded Silica Gel for Liquid Chromatography

Abstract

Acylation of aminopropyl-bonded silica gel for liquid chromatography with acid chlorides was investigated in terms of the pore structure of silica gel and the molecular size of acylating agents. Three types of aminopropyl bonded silica gel with different pore sizes, 40, 60 and 100 A, were acylated with various acid chlorides. Silica gel with larger pore size generally reacted with a larger amount of acid chloride than that with smaller pore size. This trend was more remarkable when acylating agents with larger molecular size were used. Thus, the density of ligand on the silica surface can be controlled by the combination of pore structure of silica gel and molecular size of acylating agents. Unreacted amino groups on silica surface after the acylation with stearoyl chloride could be made to react when benzoyl chloride, with a smaller molecular size, was used as a second acylating agent. © 1987, The Japan Society for Analytical Chemistry. All rights reserved.