A method of preparing a propanol sol of silica

摘要

A propanol sol of silica having a specific surface area of 25 to 550 m<2>/g, the sol having an SiO2 concentration of 10 to 50 % by weight of SiO2 and a residual content of a medium containing 7.5 % by weight or less of water based on the SiO2 content and 90 % by weight or more of propanol, is prepared by an improved process involving replacing the aqueous mediumin an acidic aqueous sol of silica containing 5 to 50 % by weight of SiO2 and a medium having a water content of 15 % by weight or more with propanol by a distillation method in which a concentration of 5 to 50 % by weight of SiO2 in the sol and 1 to 85 % by weight of methanol in the medium in the sol is maintained when the medium in the sol during the replacement contains 15 to 0.5 % by weight of water.