title: Selective Production of Toluene from Biomass-Derived Isoprene and Acrolein.
abstract: Toluene is a basic chemical that is currently produced from petroleum resources. In this paper, we report a new route for the effective synthesis of toluene from isoprene and acrolein, two reactants readily available from biomass, through a simple two-step reaction. The process includes Diels-Alder cycloaddition of isoprene and acrolein in a Zn-containing ionic liquid at room temperature to produce methylcyclohex-3-enecarbaldehydes (MCHCAs) as intermediates, followed by M (M=Pt, Pd, Rh)/Al2O3-catalyzed consecutive dehydrogenation-decarbonylation of the MCHCAs at 573 K to generate toluene with an overall yield up to 90.7 %. Model reactions indicated that a synergistic inductive effect of the C=C double bond and the aldehyde group in MCHCA plays a key role in initiating the consecutive dehydrogenation-decarbonylation, and that methyl benzaldehydes are the key intermediates in the gas-phase transformation of MCHCAs. Microcalorimetric adsorption of CO on different catalysts showed that decarbonylation of the substrate occurs more likely on the strong adsorption sites. To the best of our knowledge, it is the first report of Pt/Al2O3-catalyzed consecutive dehydrogenation-decarbonylation of a given compound in one reactor. This work provides a highly efficient and environmental friendly route to toluene by utilizing two compounds that can be prepared from biomass.
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Dai
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P.R. China.
authors.forename: Changzhi
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P.R. China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P.R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P.R. China.
authors.forename: Haiwei
authors.initials: H
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P.R. China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P.R. China.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P.R. China.
authors.forename: Aiqin
authors.initials: A
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P.R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
mesh_terms: D000171:Acrolein / Q000737:chemistry*; D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry; D018533:Biomass; D002070:Butadienes / Q000737:chemistry*; D002384:Catalysis; D055772:Green Chemistry Technology; D045782:Hemiterpenes / Q000737:chemistry*; D010420:Pentanes / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry; D014050:Toluene / Q000737:chemistry*
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene; D014050:Toluene; D010984:Platinum; D000171:Acrolein; D000537:Aluminum Oxide
keywords: Diels-Alder reaction; biomass; decarbonylation; dehydrogenation; toluene