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 |
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| 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 |
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| Affiliations |
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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
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 |