TY - JOUR

T1 - Application of parahydrogen for mechanistic investigations of heterogeneous catalytic processes

AU - Burueva, D. B.

AU - Skovpin, I. V.

AU - Zhivonitko, V. V.

AU - Salnikov, O. G.

AU - Romanov, A. S.

AU - Kovtunov, K. V.

AU - Koptyug, I. V.

PY - 2017/2/1

Y1 - 2017/2/1

N2 - Parahydrogen-induced polarization technique (PHIP), based on the pairwise addition of molecular hydrogen to a substrate, was successfully applied to obtain novel information on the mechanisms of heterogeneous catalytic hydrogenation, hydrodesulfurization, and oligomerization processes. In particular, the PHIP effects were observed upon hydrogenation with parahydrogen catalyzed by the immobilized neutral complexes of rhodium and iridium, which confirms the similarity in the mechanisms of homogeneous and heterogeneous hydrogenation for such systems. In the study of acetylene oligomerization, a significant NMR signal enhancement was revealed for a number of C4 oligomers, with the enhancement levels by far exceeding that observed in hydrogenation of carbon-carbon triple bonds. The mechanistic features of heterogeneous hydrogenation of a number of six-membered cyclic hydrocarbons over supported metal catalysts were investigated, and their hydrogenation scheme based on the pairwise addition of molecular hydrogen was proposed. Furthermore, the PHIP technique revealed that heterogeneous hydrodesulfurization of thiophene mainly proceeds via hydrogenation followed by a C—S bond cleavage. A significant enhancement of sensitivity in combination with characteristic line shapes of NMR signals make the PHIP method a unique and highly informative tool for the investigation of heterogeneous catalytic processes.

AB - Parahydrogen-induced polarization technique (PHIP), based on the pairwise addition of molecular hydrogen to a substrate, was successfully applied to obtain novel information on the mechanisms of heterogeneous catalytic hydrogenation, hydrodesulfurization, and oligomerization processes. In particular, the PHIP effects were observed upon hydrogenation with parahydrogen catalyzed by the immobilized neutral complexes of rhodium and iridium, which confirms the similarity in the mechanisms of homogeneous and heterogeneous hydrogenation for such systems. In the study of acetylene oligomerization, a significant NMR signal enhancement was revealed for a number of C4 oligomers, with the enhancement levels by far exceeding that observed in hydrogenation of carbon-carbon triple bonds. The mechanistic features of heterogeneous hydrogenation of a number of six-membered cyclic hydrocarbons over supported metal catalysts were investigated, and their hydrogenation scheme based on the pairwise addition of molecular hydrogen was proposed. Furthermore, the PHIP technique revealed that heterogeneous hydrodesulfurization of thiophene mainly proceeds via hydrogenation followed by a C—S bond cleavage. A significant enhancement of sensitivity in combination with characteristic line shapes of NMR signals make the PHIP method a unique and highly informative tool for the investigation of heterogeneous catalytic processes.

KW - heterogeneous catalysis

KW - hydrodesulfurization

KW - hydrogenation

KW - NMR signal enhancement

KW - oligomerization

KW - parahydrogen

KW - polarization

KW - reaction mechanisms

UR - http://www.scopus.com/inward/record.url?scp=85021841514&partnerID=8YFLogxK

U2 - 10.1007/s11172-017-1728-5

DO - 10.1007/s11172-017-1728-5

M3 - Article

AN - SCOPUS:85021841514

VL - 66

SP - 273

EP - 281

JO - Russian Chemical Bulletin

JF - Russian Chemical Bulletin

SN - 1066-5285

IS - 2

ER -