TY - JOUR
T1 - Hydrogenolysis and Homologation of 3,3-Dimethyl-1-butene on Ru/SiO2 catalyst
T2 - Implications for the mechanism of carbon-carbon bond formation and cleavage on metal surfaces
AU - Toyir, Jamil
AU - Leconte, Michel
AU - Niccolai, Gerald P.
AU - Basset, Jean Marie
PY - 1995/4/1
Y1 - 1995/4/1
N2 - The reactions of 3,3-dimethyl-1-butene (neohexene) with hydrogen in the presence of zero-valent ruthenium metal particles supported on silica are reported. The predominant reaction is the hydrogenation of neohexene to neohexane. Simultaneous but slower homologation and hydrogenolysis reactions are reported. The homologation and hydrogenolysis reactions run at approximately equal rates, suggesting a mechanistic link between the two processes. The relative quantities of C1-C5 and C7 products and the variation of these quantities with respect to varying temperature, neohexene/hydrogen ratio, and contact time are reported. The distribution of the primary products, neopentane, isobutene, and methane for hydrogenolysis and 2,2-dimethyl pentane, 2,2,3-trimethyl butane, and 4,4-dimethyl-1-pentene for homologation is discussed in terms of current thought on the mechanism of homologation and hydrogenolysis of alkanes. The most likely and strongly indicated mechanism for the hydrogenolysis of neohexene involves the deinsertion of a methylidene fragment from a ruthenium-neohexyl intermediate which is also an intermediate in the hydrogenation of neohexene. The distribution of C7 homologation products does not allow one to distinguish between a simple insertion mechanism and a mechanism passing through a metallacyclic intermediate.
AB - The reactions of 3,3-dimethyl-1-butene (neohexene) with hydrogen in the presence of zero-valent ruthenium metal particles supported on silica are reported. The predominant reaction is the hydrogenation of neohexene to neohexane. Simultaneous but slower homologation and hydrogenolysis reactions are reported. The homologation and hydrogenolysis reactions run at approximately equal rates, suggesting a mechanistic link between the two processes. The relative quantities of C1-C5 and C7 products and the variation of these quantities with respect to varying temperature, neohexene/hydrogen ratio, and contact time are reported. The distribution of the primary products, neopentane, isobutene, and methane for hydrogenolysis and 2,2-dimethyl pentane, 2,2,3-trimethyl butane, and 4,4-dimethyl-1-pentene for homologation is discussed in terms of current thought on the mechanism of homologation and hydrogenolysis of alkanes. The most likely and strongly indicated mechanism for the hydrogenolysis of neohexene involves the deinsertion of a methylidene fragment from a ruthenium-neohexyl intermediate which is also an intermediate in the hydrogenation of neohexene. The distribution of C7 homologation products does not allow one to distinguish between a simple insertion mechanism and a mechanism passing through a metallacyclic intermediate.
UR - http://www.scopus.com/inward/record.url?scp=0006007908&partnerID=8YFLogxK
U2 - 10.1006/jcat.1995.1084
DO - 10.1006/jcat.1995.1084
M3 - Article
AN - SCOPUS:0006007908
SN - 0021-9517
VL - 152
SP - 306
EP - 312
JO - Journal of Catalysis
JF - Journal of Catalysis
IS - 2
ER -