کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
57703 47128 2008 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Selective synthesis of para–para′-dimethyldiphenylmethane over H-beta zeolite
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Selective synthesis of para–para′-dimethyldiphenylmethane over H-beta zeolite
چکیده انگلیسی

Selective synthesis of para–para′-dimethyldiphenylmethane (para–para′-DMDPM) from the condensation between toluene and formaldehyde was investigated over H-X, H-Y, H-ZSM-5, H-mordenite and MCM-41. Characterizations (NH3-TPD-MS and pore structure) disclosed that the catalytic activity of various zeolites depends mainly on its strong acid site and accessibility of the internal pores. H-beta zeolite, with a unique pore sized in 0.66 nm and higher proportion of stronger acid site, exhibited the highest activity and stereo-selectivity (86.5%). Small sized H-beta zeolite was more active due to the enhanced accessibility of its acid site, and this kind of zeolite remained a higher stereo-selectivity (>80%) even at higher temperature, longer reaction time and recycle usage. The best yield of para–para′-DMDPM reached 71.1% at 140°C over H-beta zeolite and it could be used in recycle without loss of its structure, activity and stereo-selectivity.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Catalysis Today - Volume 131, Issues 1–4, 29 February 2008, Pages 378–384
نویسندگان
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