Modification of a surface of colloidal size silica particles by chemisorption of 2-propanol via azeotropic distillation process

Abstract

The surface properties of colloidal silica particles have been changed by chemisorption of 2-propanol on to silanol (≡Si-OH) groups in anhydrous medium via azeotropic distillation. Sodium ion stabilized silica sol was used as a source of the amorphous SiO2 particles with diameter in range 9-15 nm for utilization in sol-gel process. The hydroxyl groups (-OH) on surface were replacing by alkoxy groups (-OC3H7). The chemisorption of C3H8O on silica surface was carried out in the ternary azeotropic system isopropanol-water-benzene. The main advantage of this process is low temperature for the substitution of the isopropoxy groups for the silanols and the possibilities to the recycling of the chemicals after the esterification. DTA and FTIR methods were used for the characterization of the prepared precursor.