TY - JOUR

T1 - Mechanisms of Methylenecyclobutane Hydrogenation over Supported Metal Catalysts Studied by Parahydrogen-Induced Polarization Technique

AU - Salnikov, Oleg G.

AU - Burueva, Dudari B.

AU - Kovtunova, Larisa M.

AU - Bukhtiyarov, Valerii I.

AU - Kovtunov, Kirill V.

AU - Koptyug, Igor V.

N1 - Funding Information: O.G.S. thanks the Russian Foundation for Basic Research (grant 19‐33‐60045). D.B.B. thanks RSF (grant 21‐73‐10105) for the support of GC‐MS studies. I.V.K. thanks the Russian Foundation for Basic Research (grant 19‐29‐10003) for financial support. L.M.K. thanks the Russian Ministry of Science and Higher Education (grant AAAA‐A16‐116121510087‐5) for the support of catalysts preparation and characterization. Publisher Copyright: © 2022 Wiley-VCH GmbH

PY - 2022/4/5

Y1 - 2022/4/5

N2 - In this work the mechanism of methylenecyclobutane hydrogenation over titania-supported Rh, Pt and Pd catalysts was investigated using parahydrogen-induced polarization (PHIP) technique. It was found that methylenecyclobutane hydrogenation leads to formation of a mixture of reaction products including cyclic (1-methylcyclobutene, methylcyclobutane), linear (1-pentene, cis-2-pentene, trans-2-pentene, pentane) and branched (isoprene, 2-methyl-1-butene, 2-methyl-2-butene, isopentane) compounds. Generally, at lower temperatures (150–350 °C) the major reaction product was methylcyclobutane while higher temperature of 450 °C favors the formation of branched products isoprene, 2-methyl-1-butene and 2-methyl-2-butene. PHIP effects were detected for all reaction products except methylenecyclobutane isomers 1-methylcyclobutene and isoprene implying that the corresponding compounds can incorporate two atoms from the same parahydrogen molecule in a pairwise manner in the course of the reaction in particular positions. The mechanisms were proposed for the formation of these products based on PHIP results.

AB - In this work the mechanism of methylenecyclobutane hydrogenation over titania-supported Rh, Pt and Pd catalysts was investigated using parahydrogen-induced polarization (PHIP) technique. It was found that methylenecyclobutane hydrogenation leads to formation of a mixture of reaction products including cyclic (1-methylcyclobutene, methylcyclobutane), linear (1-pentene, cis-2-pentene, trans-2-pentene, pentane) and branched (isoprene, 2-methyl-1-butene, 2-methyl-2-butene, isopentane) compounds. Generally, at lower temperatures (150–350 °C) the major reaction product was methylcyclobutane while higher temperature of 450 °C favors the formation of branched products isoprene, 2-methyl-1-butene and 2-methyl-2-butene. PHIP effects were detected for all reaction products except methylenecyclobutane isomers 1-methylcyclobutene and isoprene implying that the corresponding compounds can incorporate two atoms from the same parahydrogen molecule in a pairwise manner in the course of the reaction in particular positions. The mechanisms were proposed for the formation of these products based on PHIP results.

KW - heterogeneous catalysis

KW - hydrogenation

KW - hyperpolarization

KW - methylenecyclobutane

KW - NMR spectroscopy

KW - parahydrogen

KW - Magnetic Resonance Spectroscopy

KW - Catalysis

KW - Hydrogen/chemistry

KW - Hydrogenation

UR - http://www.scopus.com/inward/record.url?scp=85126069964&partnerID=8YFLogxK

U2 - 10.1002/cphc.202200072

DO - 10.1002/cphc.202200072

M3 - Article

C2 - 35099100

AN - SCOPUS:85126069964

VL - 23

JO - ChemPhysChem

JF - ChemPhysChem

SN - 1439-4235

IS - 7

M1 - e202200072

ER -