%0 Journal Article
%T EffectsofcrystallinityofZSM-5zeoliteonpara-selectivetert-butylationofethylbenzene
%A PUSHPARAJ Hemalatha
%A MANI Ganesh
%A MUTHIAHPILLAI Palanichamy
%A VELAYUTHAM Murugesan
%A PARK Yong-Ki
%A CHOI Won Choon
%A JANG Hyun Tae
%J ´ß»¯Ñ§±¨
%P 294-304
%D 2013
%R 10.1016/S1872-2067(11)60482-8
%X £¿HighlycrystallineZSM-5zeolitesareimportantforpara-selectivealkylationofalkylaromatics,becausetheycarryfewexternalacidsitesforisomerizationofp-dialkylproducts.Suchzeolites(Si/Al=25,50,and75)weresynthesizedinafluoridemediumbetweenpH4and6.Theircrystallinities,crystalsizes,andsurfaceareaswerehigherthanthoseofacommercialZSM-5zeolite.Theirparaselectivitiesinalkylationweretestedforvapor-phasetert-butylationofethylbenzenebetween200and400¡ãC.Asexpected,allthecatalystsshowedmorethan90%paraselectivity.At300¡ãC,ethylbenzeneconversiondecreasedintheorderZSM-5(25,commercial)>ZSM-5(25)>ZSM-5(50)>ZSM-5(75).Thecatalystshadweak,medium,andstrongacidsites,butalltheacidsitesofZSM-5(75)wereweakerthanthoseofZSM-5(25)andZSM-5(50).ThehighactivityofcommercialZSM-5wascausedbyitsstrongacidsitesbeingstrongerthanthoseofthesynthesizedzeolites.Althoughtheactivityofthecommercialcatalystwashigherthanthoseofthepresentcatalysts,theselectivityfor4-t-butylethylbenzene(4-t-BEB)waslow.Theoptimumfeedratio(ethylbenzene:t-butylalcohol)was2:1andthefeedratewas1.65h£¿1forhighethylbenzeneconversionand4-t-BEBselectivity.Time-on-streamstudiesshowedslowcatalystdeactivation.HighlycrystallineZSM-5zeolitesarethereforebetterthanacommercialzeoliteforpara-selectivealkylationofalkylaromatics.Theydonotrequiremuchpost-modificationforhighparaselectivity.Afluoridemediumisthereforebetterthananalkalinemediumforobtaininghighlycrystallinepara-selectiveZSM-5zeolites.
%K ZSM-5
%K Fluoridemedium
%K p-selectivity
%K Ethylbenzene
%K Tert-butylation
%K Zeolite
%U http://www.chxb.cn/CN/abstract/abstract20899.shtml