Changes in surface and catalytic dehydration activities of 2-propanol on AlPO-5 induced by silver impregnation

Five samples of pure Al-Phosphates (ALPO-5) and silver oxide impregnated Al -Phosphates (wt.% of Ag = 1.5-8.0) were prepared. The structural characteri zation was studied using X-ray diffraction (XRD) and FT-IR techniques. The textural properties (surface area end mean pore radius) were determined fro m N-2 adsorption at 77 K. Surface acidities of all prepared samples was est imated by nonaqueous titration of solid catalysts with n-butylamine using H ammett's indicators. The catalytic conversion of 7-propanol at 300 degrees C was also performed using microcatalytic pulse technique. Both XRD and FT- IR techniques give the characteristic ALPO-5 patterns only, whereas Ag2O-Al PO-5 or silver-aluminium phosphate spinel were not be detected. The surface area, mean pore radius, surface acidity and catalytic activity were overal l increased upon increasing the loading amounts of silver. Pure and silver impregnated aluminium phosphates show no dehydrogenation (DHG) activity. Im pregnation with silver favors dehydration of 2-propanol to ether via interm olecular reaction which can proceed on weak acid sites. (C) 1999 Elsevier S cience B.V. All rights reserved.