Phenylated silica gel was prepared by the reaction between the surface hydroxyl groups of silica gel and PhSiCl3. The phys. structure, water vapor adsorption isotherms, heat of wetting, DTA, and IR for phenylated silica gel were determine The phenylated silica gels show a remarkable decrease in water vapor adsorption, and in heat of wetting for water, benzene, and cyclohexane. The thermal stability of phenylated silica gel is greater than that of methylated silica gel. The surface of methylated silica gel is highly hydrophobic, but the hydrophobicity of phenylated silica gel is very weak.

Key words: INFRARED SPECTROPHOTOMETRY, THERMAL STABILITY, BENZENE P, SURFACE PROPERTY, SILICA GEL, DIFFERENTIAL THERMAL ANALYSIS, TRICHLOROSILANE, PORE STRUCTURE