%0 Journal Article
%T NaOHmodifiedWO3/SiO2catalystsforpropyleneproductionfrom2-buteneandethylenemetathesis
%A Surasa Maksasithorn
%A Damien P. Debecker
%A Piyasan Praserthdam
%A Joongjai Panpranot
%A Kongkiat Suriye
%A Sirachaya Kunjara Na Ayudhya
%J ´ß»¯Ñ§±¨
%P 232-241
%D 2014
%R 10.1016/S1872-2067(12)60760-8
%X £¿AWO3/SiO2catalystisusedinindustrytoproducepropylenefrom2-buteneandethylenemetathesis.CatalystswithvariousWO3loading(4%to10%)werepreparedbyimpregnationandtestedforthemetathesisofetheneandtrans-2-butene.IonexchangeofNaOHontotheWO3/SiO2catalystwasusedtomitigatetheacidityofthecatalystsinacontrolledway.AtlowWO3loading,thetreatmentwithlargeamountsofNaOHresultedinasignificantdecreaseinmetathesisactivityconcomitantwithsignificantWleachingandmarkedstructuralchanges(XRD,Raman).AthigherWO3loading(6%to10%),thetreatmentwithNaOHmainlyresultedinadecreaseinacidity.FT-IRexperimentsafteradsorptionofpyridineshowedthattheLewisacidicsiteswerepoisonedbysodium.Nevertheless,themetathesisactivityremainedconstantaftertheNaOHtreatment.Thissuggestedthattheremainingacidityonthecatalystwasenoughtoensuretheefficientformationofthecarbeneactivesites.Interestingly,Napoisoningresultedinsomemodificationoftheselectivity.Themitigationofaciditywasshowntofavorpropeneselectivityovertheformationofisomerizationproducts(cis-2-butene,1-butene,etc.).Moreover,treatmentwithNaOHledtoashorterinductionperiodandreducedcokeformationontheWO3/SiO2catalyst.
%K Propylene
%K Olefinmetathesis
%K Tungstentrioxide
%K Silicondioxide
%K Sodiumhydroxidetreatment
%K Acidity
%K Pyridine
%U http://www.chxb.cn/CN/abstract/abstract21229.shtml