TRANSITION-METAL PROMOTED ALPO4 CATALYST-2 - THE CATALYTIC ACTIVITY OF M0.05AL0.95PO4 FOR ALCOHOL CONVERSION AND CUMENE CRACKING DEHYDROGENATION REACTIONS/

The 2-propanol and methanol conversion over M0.05Al0.95PO4 (M = VO, Cr , Mn, Fe, Co, or Ni) catalysts was studied at different temperatures a nd flow rates in a fixed bed catalytic reactor while cumene cracking/d ehydrogenation reaction was carried out in a micropulse reactor. The l ow acetone selectivity from 2-propanol in nitrogen and air indicated t he presence of an insufficient number of weak redox sites in all sampl es. Among all the samples, VOAlPO4 showed the highest conversion and a lso selectivity for olefins. Selectivity studies indicated that 2-prop anol and methanol dehydration followed a combination of parallel and c onsecutive pathways. On all the samples, selectivity of cumene crackin g product is very low. However, all the samples showed appreciable deh ydrogenation activity. Participation of Bronsted acid sites in the deh ydration as well as cracking reactions is supported by the surface poi soning studies. A good correlation was observed between the acidity an d the dehydration activity of all the samples. (C) 1998 Elsevier Scien ce B.V.