Isomorphous substitution of chromium in AlPO-11 and AlPO-5 framework and their applications in the aromatization of 3-carene

Abstract

605-609CrAPO-11 and CrAPO-5 have been synthesized hydrothermally using aluminium isopropoxide, H3PO4, Cr(NO3)3 and di-n-propylamine for CrAPO-11 and triethylamine for CrAPO-5. The isomorphous substitution of Cr in AlPO-11 and AlPO-5 framework has been confirmed by XRD, SEM, DRS. MAS NMR, TGA, pore-volume and chemical analysis. Formation of cymenes (p-cymene and m-cymene) from 3-carene is higher over reduced than that over oxidized catalysts. The higher plm (p-cymene/ m-cymene) ratio, observed over reduced than over oxidized catalysts shows that p-cymene does not isomerise to m-cymene. The poisoning effects of pyridine and 4-methylquinoline are the same over large pore CrAPO-5 but different over medium pore CrAPO-11