\nChristo\u00adpher P. Nicholas<\/strong>
\n<\/em>
\n
\nAbstract<\/strong> \u2014 Tung\u00adsten oxide sup\u00adport\u00aded on sil\u00adi\u00adca is an effi\u00adcient cat\u00ada\u00adlyst for olefin metathe\u00adsis used in indus\u00adtri\u00adal process\u00ades since the 1960s. Sev\u00ader\u00adal ele\u00adments point to iso\u00adlat\u00aded met\u00adal cen\u00adters as the active sites, and from the Chau\u00advin mech\u00ada\u00adnism, it is rea\u00adson\u00adable to expect that car\u00adbene species are involved, pos\u00adsi\u00adbly bear\u00ading an oxide lig\u00adand in the metal\u2019s lig\u00adand sphere. Owing to the strate\u00adgic impor\u00adtance of olefins as build\u00ading blocks for the world chem\u00adi\u00adcal indus\u00adtry, devel\u00adop\u00adment of effi\u00adcient process\u00ades is of utmost rel\u00ade\u00advance. More specif\u00adi\u00adcal\u00adly, tai\u00adlored het\u00adero\u00adge\u00adneous cat\u00ada\u00adlysts with known structure\u2013activity rela\u00adtion\u00adships may improve life\u00adtimes and have high\u00ader num\u00adbers of active sites.<\/p>\n
With our col\u00adlab\u00ado\u00adra\u00adtors, we have been study\u00ading tung\u00adsten hydride sup\u00adport\u00aded on alu\u00admi\u00adna pre\u00adpared by the sur\u00adface organometal\u00adlic chem\u00adistry method as an active pre\u00adcur\u00adsor for metathe\u00adsis process\u00ades at low tem\u00adper\u00ada\u00adture and pres\u00adsure. Taoufik, et\u200b.al.<\/em> showed that eth\u00adyl\u00adene can be con\u00advert\u00aded to propy\u00adlene at very high selec\u00adtiv\u00adi\u00adties of 99% via a tri-func\u00adtion\u00adal mech\u00ada\u00adnism involv\u00ading dimer\u00adiza\u00adtion, iso\u00admer\u00adiza\u00adtion and cross-metathe\u00adsis of eth\u00adyl\u00adene and the pro\u00adduced 2-butene. Recent\u00adly, via a con\u00adtact time study we revealed that the dimer\u00adiza\u00adtion of eth\u00adyl\u00adene to 1-butene is the pri\u00adma\u00adry and also the rate lim\u00adit\u00ading step in this reac\u00adtion and results in deac\u00adti\u00adva\u00adtion of the cat\u00ada\u00adlyst due to a side reac\u00adtion like olefin poly\u00admer\u00adiza\u00adtion pro\u00adduc\u00ading car\u00adbona\u00adceous deposits on the cat\u00ada\u00adlyst.<\/p>\n With that knowl\u00adedge, we have also inves\u00adti\u00adgat\u00aded per\u00adfor\u00admance of the cat\u00ada\u00adlyst in the pres\u00adence of eth\u00adyl\u00adene and butenes. At low tem\u00adper\u00ada\u00adture (120 \u00b0C) in the cross-metathe\u00adsis of eth\u00adyl\u00adene and 2-butene, the cat\u00ada\u00adlyst deac\u00adti\u00advates notably with time on stream. How\u00adev\u00ader, at 150 \u00b0C, the cat\u00ada\u00adlyst was sta\u00adble with time and there\u00adby gave a high pro\u00adduc\u00adtiv\u00adi\u00adty in propy\u00adlene. The ratio of eth\u00adyl\u00adene to trans-2-butene was also stud\u00adied, and the W-H\/Al2<\/sub>O3<\/sub> cat\u00ada\u00adlyst is sta\u00adble and high\u00adly selec\u00adtive to propy\u00adlene even at sub-sto\u00adi\u00adchio\u00admet\u00adric eth\u00adyl\u00adene ratios.<\/p>\n Sur\u00adpris\u00ading\u00adly, we have also been able to obtain propy\u00adlene in high yields from butene only feeds. 1-butene and 2-butene are both able to be con\u00advert\u00aded into propy\u00adlene at high\u00ader selec\u00adtiv\u00adi\u00adty than expect\u00aded due to iso\u00admer\u00adiza\u00adtion and metathe\u00adsis occur\u00adring simul\u00adta\u00adne\u00adous\u00adly. Then, by study\u00ading isobutene \/ 2-butene cross-metathe\u00adsis, we observed that the cat\u00adalyt\u00adic cycle involv\u00ading the less ster\u00adi\u00adcal\u00adly hin\u00addered tungsta\u00adcy\u00adclobu\u00adtane inter\u00adme\u00addi\u00adate gov\u00aderns the con\u00adver\u00adsion rate of the cross-metathe\u00adsis reac\u00adtion for propy\u00adlene pro\u00adduc\u00adtion from butenes and\/or eth\u00adyl\u00adene.
\n <\/p>\nReferences<\/h4>\n
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![\"Christopher_P_Nicholas\"](\"http:\/\/catalysisclubphilly.org\/awe9a91v\/uploads\/2014\/03\/Christopher_P_Nicholas.png\")
<\/a>Biog\u00adra\u00adphy<\/strong> \u2014 Chris joined UOP in 2006 after earn\u00ading a Ph.D. from North\u00adwest\u00adern Uni\u00adver\u00adsi\u00adty and work\u00ading in the Hard Mate\u00adri\u00adals Cen\u00adter of Excel\u00adlence at Sig\u00adma-Aldrich. He has worked in the Catal\u00ady\u00adsis and Explorato\u00adry Research depart\u00adments and is cur\u00adrent\u00adly focused on New Mate\u00adri\u00adals Research. Chris is an inven\u00adtor or co-inven\u00adtor on 30+ US and for\u00adeign patents and coau\u00adthor of 13 peer reviewed jour\u00adnal arti\u00adcles and a book chap\u00adter. He has been involved with the Chica\u00adgo Catal\u00ady\u00adsis Club since grad\u00adu\u00adate stu\u00addent days and is cur\u00adrent\u00adly serv\u00ading as the Pro\u00adgram Chair for the Chica\u00adgo Catal\u00ady\u00adsis Club. Chris\u2019 research inter\u00adests encom\u00adpass the gamut of inor\u00adgan\u00adic and cat\u00adalyt\u00adic tech\u00adnolo\u00adgies rang\u00ading from mate\u00adri\u00adals syn\u00adthe\u00adsis to char\u00adac\u00adter\u00adi\u00adza\u00adtion to cat\u00ada\u00adlyst and process devel\u00adop\u00adment. He has par\u00adtic\u00adu\u00adlar\u00adly enjoyed under\u00adstand\u00ading the rela\u00adtion\u00adship between homo\u00adge\u00adneous and het\u00adero\u00adge\u00adneous cat\u00ada\u00adlysts.<\/p>\n","protected":false},"excerpt":{"rendered":"