Studies on synthesis of para-isopropylphenol over the P-HZSM-5 catalyst

Alkylation of phenol with isopropanol to para-isopropylphenol (p-IPP) over P-HZSM-5 catalyst has been studied. The influence of phosphorus modificatio n on catalytic performance of HZSM-5 has been investigated. The acidic site density and acid types were determined by means of NH3-TPD and Pyr-IR. The selectivity of p-IPP increased to 95% while the conversion of phenol and t he acidic site density decreased on the HZSM-5 after modified with NH4H2PO4 . In the preparation of P-HZSM-5, it appeared that there was an interaction between phosphorus and HZSM-5 zeolite, which resulted in framework dealumi nation on HZSM-5, and calcination influenced both activity and p-IPP select ivity. The selectivity of P-HZSM-5 reached the highest when the support and the catalyst were calcined at 973 K and 823 K, respectively.