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Hydrogenation of Unsaturated Six-Membered Cyclic Hydrocarbons Studied by the Parahydrogen-Induced Polarization Technique Full article

Journal The Journal of Physical Chemistry C
ISSN: 1932-7447 , E-ISSN: 1932-7455
Output data Year: 2016, Volume: 120, Number: 25, Pages: 13541-13548 Pages count : 8 DOI: 10.1021/acs.jpcc.6b03267
Tags Atoms; Benzene; Catalysts; Cyclohexane; Hydrocarbons; Nuclear magnetic resonance spectroscopy; Olefins; Palladium; Polarization; Toluene
Authors Burueva Dudari B. 1,2 , Salnikov Oleg G. 1,2 , Kovtunov Kirill V. 1,2 , Romanov Alexey S. 1,2 , Kovtunova Larisa M. 2,3 , Khudorozhkov Alexander K. 2,3 , Bukhtiyarov Andrey V. 2,3 , Prosvirin Igor P. 2,3 , Bukhtiyarov Valerii I. 2,3 , Koptyug Igor V. 2,3
Affiliations
1 International Tomography Center, SB RAS, 3A Institutskaya St., 630090 Novosibirsk, Russia
2 Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
3 Boreskov Institute of Catalysis, SB RAS, 5 Acad. Lavrentiev Pr., 630090 Novosibirsk, Russia

Funding (7)

1 Russian Science Foundation 14-23-00146
2 Federal Agency for Scientific Organizations 0333-2014-0001 (V.44.1.1)
3 Russian Foundation for Basic Research 16-03-00407
4 Russian Foundation for Basic Research 14-03-93183
5 Russian Foundation for Basic Research 14-03-00374
6 The Ministry of Education and Science of the Russian Federation МК-4498.2016.3
7 Russian Science Foundation 14-13-00445

Abstract: Parahydrogen-induced polarization (PHIP) is an efficient technique for mechanistic investigations of homogeneous and heterogeneous catalytic hydrogenations. Herein, heterogeneous gas phase hydrogenation of six-membered cyclic hydrocarbons (benzene, toluene, cyclohexene, 1,3-cyclohexadiene and 1,4-cyclohexadiene) over Rh/TiO2, Pd/TiO2, and Pt/TiO2 catalysts was studied using PHIP. As expected, cyclohexene hydrogenation led to the formation of cyclohexane which because of its symmetry should not exhibit any PHIP effects. However, the presence of 13C nuclei at natural abundance (1.1%) breaks molecular symmetry, resulting in the observation of 13C satellite signals exhibiting PHIP effects in the 1H NMR spectra. In experiments with cyclohexene, the reactant's NMR signals were also polarized, demonstrating the possibility of cyclohexene dehydrogenation to 1,3-cyclohexadiene and subsequent hydrogenation to cyclohexene. In the hydrogenation of 1,3-cyclohexadiene and 1,4-cyclohexadiene, all NMR signals of cyclohexene exhibited PHIP effects, implying migration of C=C bonds in 1,4-cyclohexadiene and cyclohexene. At the same time, upon hydrogenation of benzene and toluene the reaction products were those with saturated cycles exclusively (cyclohexane and methylcyclohexane, respectively), and their NMR signals were not polarized. The absence of PHIP effects for arene hydrogenation can be explained by a difference in the reaction mechanism compared to cyclohexane and cyclohexadienes hydrogenations, along with the larger extent to which hydrogen atoms undergo migration on the catalyst surface facilitated by lower catalyst coverage with an adsorbed substrate in case of arenes. © 2016 American Chemical Society.
Cite: Burueva D.B. , Salnikov O.G. , Kovtunov K.V. , Romanov A.S. , Kovtunova L.M. , Khudorozhkov A.K. , Bukhtiyarov A.V. , Prosvirin I.P. , Bukhtiyarov V.I. , Koptyug I.V.
Hydrogenation of Unsaturated Six-Membered Cyclic Hydrocarbons Studied by the Parahydrogen-Induced Polarization Technique
The Journal of Physical Chemistry C. 2016. V.120. N25. P.13541-13548. DOI: 10.1021/acs.jpcc.6b03267 WOS Scopus РИНЦ ANCAN OpenAlex
Dates:
Submitted: Mar 31, 2016
Accepted: Jun 2, 2016
Published online: Jun 16, 2016
Published print: Jun 30, 2016
Identifiers:
Web of science: WOS:000379456800027
Scopus: 2-s2.0-84976907963
Elibrary: 26838732
Chemical Abstracts: 2016:906828
Chemical Abstracts (print): 165:80468
OpenAlex: W2410306622
Citing:
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Web of science 22
Scopus 21
Elibrary 22
OpenAlex 20
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