CHROMIUM-ALUMINUM ORTHOPHOSPHATES .2. EFFECT OF ALPO4 LOADING ON STRUCTURE AND TEXTURE OF CRPO4-ALPO4 (20-50-WT-PERCENT ALPO4 CATALYSTS OBTAINED IN AQUEOUS AMMONIA

The AlPO4 content in CrPO4-AlPO4 (CrAlP-A) systems has a marked influe nce on thermal behavior, speeding up the transformation of amorphous C rPO4 to crystalline beta-CrPO4. Thus, XRD analysis showed that amorpho us systems are formed at AlPO4 loadings less than 50 wt.% and calcinat ion temperatures below 1273 K. Moreover, on 50 wt.% AlPO4 developed cr ystalline beta-CrPO4 in CrAlP-A systems for every calcination temperat ure. Besides, at 1273 K crystalline systems (beta-CrPO4 and tridimite- AlPO4) are formed for every composition. Moreover, surface area at any calcination temperature increases with the rise in the AlPO4 content. Also, a surface area decrease on increasing calcination temperature i s shown. Furthermore, CrAlP-A catalysts thermally treated below 1273 K only exhibited hydrogen bonded hydroxy groups (nu(O-H) similar or equ al to 3450 cm(-1)).