Abstract: The zeolite beta modified by phosphorus at normal and high temperature was characterized by thermogravimetric, NMR and acid analysis, and their alkylation performance for benzene with propylene was investigated. The analysis shows that after introduction of ammonium ion into zeolite beta at high temperature, an obvious peak appears at 220-230 ℃ in DTG curve, indicating the ammonium ions coming into the zeolite; and 31P MAS NMR and 27Al MAS NMR of zeolite shows two strong peaks at chemical shift -30.908 and 41.392, demonstrating the formation of tetracoordinated structure of P (4Al) and Al (4P); The modification leads more acid sites and stranger acid, proved by NH3-TPD analysis. The alkylation performance is improved significantly after modification of the zeolite at high temperature.

Key words: phosphorus modification, ammonium dihydrogen phosphate, zeolite beta, Alkylation