Shape-selective methylation of 4-methylbiphenyl to 4,4 '-dimethylbiphenyl over zeolite HZSM-5 modified with metal oxides of MgO, CaO, SrO, BaO, and ZnO
2003 (English)In: Catalysis Letters, ISSN 1011-372X, E-ISSN 1572-879X, Vol. 87, no 02-jan, 25-29 p.Article in journal (Refereed) Published
A series of ZSM-5 samples modified with metal oxides MO(M = Mg, Ca, Sr, Ba and Zn) were employed for the alkylation of 4-methylbiphenyl (4-MBP) with methanol to 4,4'-dimethylbiphenyl (4,4'-DMBP) under fixed-bed down-flow conditions. The methylation results showed that the use of basic metal oxides can effectively enhance the selectivity to the target product 4,4'-DMBP. MgO is the most effective modifier among the metal oxides used and it can improve selectivity to 4,4'-DMBP up to 80% as compared to only 13% over the parent zeolite HZSM-5. The modi. cation effectiveness of metal oxides on 4,4'-DMBP selectivity can be arranged in the order MgO> SrO similar to ZnO similar to CaO> BaO. The optimization of MgO modi. cation through the content, salt types and loading methods revealed that proper MgO loading (5.6 wt%) can be more effective, and the impregnation method is much better than ion exchange. The correlation of physicochemical properties (TPD, TGA, chemical analysis and chemical adsorption, etc.) of the modified HZSM-5 with the catalytic data showed that the high selectivity over ZSM-5 modified with MgO largely results from the effective suppression of 4,4'-DMBP secondary reactions such as isomerization, dealkylation and alkylation.
Place, publisher, year, edition, pages
2003. Vol. 87, no 02-jan, 25-29 p.
shape selectivity, 4-methylbiphenyl, methylation, HZSM-5, modification, polynuclear aromatics, specialty chemicals, alkylation, catalysts, naphthalene
IdentifiersURN: urn:nbn:se:kth:diva-22332ISI: 000181620600004OAI: oai:DiVA.org:kth-22332DiVA: diva2:341030
QC 201005252010-08-102010-08-10Bibliographically approved