title: Regioselectivity and Reaction Mechanism of Ru-Catalyzed Hydrogenolysis of Squalane and Model Alkanes.
abstract: The dependence of the C-C hydrogenolysis activity on reaction parameters and the structure of the substrate alkanes was investigated for Ru/CeO2catalyst with very small (dispersion: H/Ru=0.89) Ru particles. The substrate concentration and reaction temperature did not have a significant effect on the selectivity pattern, except that methane production was promoted at high temperatures. However, the hydrogen pressure had a marked effect on the selectivity pattern. Ctertiary-C bond dissociation, terminal Csecondary-Cprimarybond dissociation, and fragmentation to form excess methane had negative reaction order with respect to hydrogen partial pressure, whereas Csecondary-Csecondarybond dissociation had an approximately zero reaction order. Therefore, a high hydrogen pressure is essential for the regioselective hydrogenolysis of Csecondary-Csecondarybonds in squalane. Ru/SiO2catalyst with larger Ru particles showed similar changes in the product distribution during the change in hydrogen pressure. The reaction mechanism for each type of C-C bond dissociation is proposed based on reactivity trends and DFT calculations. The proposed intermediate species for the internal Csecondary-Csecondarydissociation, terminal Csecondary-Cprimarydissociation, and Ctertiary-C dissociation is alkyls, alkylidynes, and alkenes, respectively.
authors.affiliation: Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan.|Research Center for Rare Metal and Green Innovation, Tohoku University, 468-1, Aoba, Aramaki, Aoba-ku, Sendai, 980-0845, Japan.
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Nakagawa
authors.affiliation: Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Oya
authors.affiliation: Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kanno
authors.affiliation: Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Nakaji
authors.affiliation: Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan.|Research Center for Rare Metal and Green Innovation, Tohoku University, 468-1, Aoba, Aramaki, Aoba-ku, Sendai, 980-0845, Japan.
authors.forename: Masazumi
authors.initials: M
authors.lastname: Tamura
authors.affiliation: Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan.|Research Center for Rare Metal and Green Innovation, Tohoku University, 468-1, Aoba, Aramaki, Aoba-ku, Sendai, 980-0845, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Tomishige
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011312:Pressure; D012428:Ruthenium / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013185:Squalene / Q000031:analogs & derivatives* / Q000737:chemistry; D013237:Stereoisomerism; D013379:Substrate Specificity; D013499:Surface Properties; D013696:Temperature
chemical_list: D000473:Alkanes; D012822:Silicon Dioxide; D013185:Squalene; D012428:Ruthenium; D006859:Hydrogen; C019556:squalane
keywords: alkanes; hydrogenolysis; regioselectivity; ruthenium; surface species