Esterification of acetic acid with N-butanol over the catalysts of surface hydrophobicity and lipophobicity

A series of silica-supported silicotungstic acid catalysts (H4SiW12O40, abbreviated as HSiW), modified with various loadings of Teflon (HSiW/SiO2-Teflon), were prepared by impregnation method. The surface properties of the catalysts were studied by means of XRD, BET, NH3-TPD and the Drop Shape Analyzer (DSA) measurements. Both the surface hydrophobicity and the surface lipophobicity of HSiW/SiO2-Teflon catalysts are enhanced by means of the addition of Teflon. HSiW/SiO2-Teflon exhibit better activity than that of HSiW/SiO2 in the esterification of acetic acid with n-butanol. Surface hydrophobicity and lipophobicity of the catalysts lead to more effective to remove product molecules and decrease the interaction between H2O molecules and the catalyst surface, especially at low reaction temperature and appropriate WHSV.