STUDIES ON THE ACIDITY-REDUCIBILITY AND C ATALYTIC PROPERTIES OF NIHYZEOLITES

The structure, acidity, reducibility of Ni2(+) and the reaction of tol uene conversion of NiHY zeolite have been studied by using XRD, NH3-TP D, Py-IR, TPR and toluene conversion reaction. It is found that both t he number and the strength of acid sites on NiHY zeolite increase with increasing nickel content, and the number of Bronsted acid sites decr ease, while the number of Lewis acid sites increase. Otherwise, there are two peaks of H-2 consumption, in the range of 573-673 K and 973-10 73 K, respectively, which appear in TPR spectra of NiHY zeolite, and t heir area increases with the increase of nickel content. The results o f the reaction of toulene conversion over NiHY zeolite indicate that t he products of aromatic ring opening and demethylation increase marked ly, while the product of disproportionation decreases greatly with the increase of nickel content in NiHY. Associated with the data of acidi ty and reducibility of Ni2(+), the change of the selectivity of toluen e conversion over NiHY zeolite has been discussed.