Performance of HZSM-5 as Catalyst for Alkylation of Methyl-naphthalene with Methanol in Supercritical Phase  

作　　者：BAI Xue-feng WU Wei HU Hao-quan 

机构地区：[1]School of Chemical Engineering, Dalian University of Technology, Dalian 116012, P. R. China [2]Heilongjiang Institute of Petrochemistry, Harbin 150040, P. R. China [3]School of Chemistry and Chemical Engineering, Heilongjiang University, Harbin 150001, P. R. China

出　　处：《Chemical Research in Chinese Universities》2005年第6期680-683,共4页高等学校化学研究（英文版）

基　　金：SupportedbytheNationalNaturalScienceFoundationofChina(No.20276011&No.20376012).

摘　　要：The alkylation of methylnaphthalene（MN） with methanol in the presence of HZSM-5 is a promising route for producing 2,6-dimetylnaphthalene（2,6-DMN） with a high selectivity. However, the conversion of MN is very low and the catalyst will be deactivated rapidly with increasing time on stream. In this study, the effects of the reaction pressure on the reactivity, selectivity and life of the catalyst of alkylation of MN over HZSM-5 modified by BaO were investigated. It was observed that with the enhancement of pressure, the conversion of MN increased, but the selectivity of 2,6-DMN kept unchanged, which was about 40% -42%. When the alkylation was carried out under a supercritical condition, the conversion of MN was 3-6 times higher and the life of catalyst was 25-30 times longer than those at an ambient pressure. The thermogravimetric analyses of the deactivated catalysts at different reaction pressures indicate that the amount of coke deposited on the catalysts was about 10% to 12 %, and the coke-burning reactions mainly took place in a temperature range from 720 to 860 K, and the apparent activation energies of the coke-burning catalysts at 0. 1 MPa（ 10 h） and 7. 6 MPa（ 108 h） were, respectively, 65.90 and 84. 72 kJ/mol. It is concluded from tile results that the supercritical condition is advantageous to enhancing the conversion of alkylation and extraction in situ, and to transporting those high molecular-weight poly-aromatic compounds so as to extend the catalyst life successively.The alkylation of methylnaphthalene（MN） with methanol in the presence of HZSM-5 is a promising route for producing 2,6-dimetylnaphthalene（2,6-DMN） with a high selectivity. However, the conversion of MN is very low and the catalyst will be deactivated rapidly with increasing time on stream. In this study, the effects of the reaction pressure on the reactivity, selectivity and life of the catalyst of alkylation of MN over HZSM-5 modified by BaO were investigated. It was observed that with the enhancement of pressure, the conversion of MN increased, but the selectivity of 2,6-DMN kept unchanged, which was about 40% -42%. When the alkylation was carried out under a supercritical condition, the conversion of MN was 3-6 times higher and the life of catalyst was 25-30 times longer than those at an ambient pressure. The thermogravimetric analyses of the deactivated catalysts at different reaction pressures indicate that the amount of coke deposited on the catalysts was about 10% to 12 %, and the coke-burning reactions mainly took place in a temperature range from 720 to 860 K, and the apparent activation energies of the coke-burning catalysts at 0. 1 MPa（ 10 h） and 7. 6 MPa（ 108 h） were, respectively, 65.90 and 84. 72 kJ/mol. It is concluded from tile results that the supercritical condition is advantageous to enhancing the conversion of alkylation and extraction in situ, and to transporting those high molecular-weight poly-aromatic compounds so as to extend the catalyst life successively.

关 键 词：METHYLNAPHTHALENE ALKYLATION Shape-selective catalysis Supercritical phase Coke-burning 

分 类 号：O643.3[理学—物理化学]