Production of para-methylstyrene and para-divinylbenzene from furanic compounds

2017 Spring Symposium

Mol­ly Koehle and Raul Lobo, Chem­i­cal and Bio­mol­e­c­u­lar Engi­neer­ing, Uni­ver­si­ty of Delaware, Newark, DE

Abstract — Of the three iso­mers of methyl­styrene, para-methyl­styrene is high­ly desir­able because it yields poly­mers with supe­ri­or prop­er­ties over poly­styrene and mixed poly-methyl­styrene [1]. How­ev­er, con­trol­ling the sub­sti­tu­tion of methyl­styrene via direct acy­la­tion or alky­la­tion of toluene is dif­fi­cult because even though the para iso­mer is favored, meta and ortho iso­mers are also formed [1, 2], and sep­a­ra­tion of the iso­mer mix­ture is very dif­fi­cult due to their near­ly iden­ti­cal prop­er­ties.

The Diels-Alder cycload­di­tion and dehy­dra­tion of sub­sti­tut­ed furans with eth­yl­ene is a plau­si­ble route to p-methyl­styrene since it is inher­ent­ly selec­tive to para aro­mat­ic species. We have suc­cess­ful­ly devel­oped a three-step cat­alyt­ic route to p-methyl­styrene from methyl­fu­ran (Scheme 1) at high yield and very high iso­mer selec­tiv­i­ty. The process uses Friedel-Crafts acy­la­tion, selec­tive reduc­tions with hydro­gen and Diels-Alder cycload­di­tion with eth­yl­ene. The raw materials—furans, eth­yl­ene and acetic acid—can all be derived from bio­mass [3,4], thus allow­ing ‘green’ styrene pro­duc­tion from renew­able car­bon sources. This approach has also been extend­ed to the pro­duc­tion of p-divinyl­ben­zene. As the acy­la­tion step is known to be cat­alyzed by Lewis acids, recent work has focused on study­ing this step on Brøn­st­ed and Lewis acid zeo­lites and will be pre­sent­ed as well.

Scheme 1: Pro­duc­tion of para-methyl­styrene from methyl­fu­ran

[1] W.W. Kaed­ing and G.C. Bar­ile, in: B.M. Cul­bert­son and C.U. Pittman, Jr. (Eds.), New Monomers and Poly­mers, Plenum Press, New York, NY, 1984, pp. 223–241.
[2]“Aromatic Sub­sti­tu­tion Reac­tions.” http://​www2​.chem​istry​.msu​.edu/​f​a​c​u​l​t​y​/​r​e​u​s​c​h​/​V​i​r​t​T​x​t​J​m​l​/​b​e​n​z​r​x​1​.​htm
[3] A.A. Rosatel­la; S.P. Sime­onov; R.F.M. Frade, R.F.M..; C.A.M. Afon­so, Green Chem., 13 (2011) 754.
[4] C.H. Chris­tensen; J. Rass-Hansen; C.C. Mars­den; E. Taarn­ing; K. Ege­blad, Chem­SusChem, 1 (2008) 283.

Biog­ra­phy — Mol­ly obtained her B.S. in Chem­i­cal Engi­neer­ing from the Uni­ver­si­ty of Pitts­burgh and her M.S. in Chem­i­cal Engi­neer­ing from the Uni­ver­si­ty of Con­necti­cut. She has worked at the Catal­y­sis Cen­ter for Ener­gy Inno­va­tion in Prof. Raul Lobo’s group since 2013. Her work focus­es on trans­for­ma­tions of bio­mass to fuels and chem­i­cals with Bron­st­ed and Lewis acid zeo­lites.