Recent developments in the surface and catalytic chemistry of supported organoactinides

TY - JOUR

T1 - Recent developments in the surface and catalytic chemistry of supported organoactinides

AU - Eisen, Moris S.

AU - Marks, Tobin J.

N1 - Funding Information: We are gratefult o the Division of Chemical Sciences, Office of Basic Energy Science, Office of Energy Research, US Department of Energy, for support of this research under Grant DE-FG0246ER13511. We thank Professor Robert J. Burwell Jr. for helpful discussions. M.S.E. acknowledgest he Weiz-

PY - 1994/1/3

Y1 - 1994/1/3

N2 - The adsorption of organoactinide complexes on dehydroxylated alumina (DA) yields coordinatively unsaturated, highly active catalysts for several demanding chemical transformations. Thus, in the case of Th(η3-allyl)4 supported on dehydroxylated γ-alumina (DA), facile arene hydrogenation and alkane activation processes can be effected in slurry reactions at 90°C and PH2 = 30-180 psi. Benzene reduction occurs at a turnover frequency of ≈ 25000 h-1 per active site and cyclohexane CH exchange with D2 at ≈ 1300 h-1 per active site. Active site characterization using D2O poisoning, hydrogenolysis, and CH3Cl dosing indicates ≤ 8 ± 1 % of the Th surface sites are catalytically significant. EPR and XPS spectroscopy provide no evidence for Th oxidation states less than +4. The mechanisms for the above processes are discussed in terms of electrophilic "four-center" activation processes in which the active sites appear to bear sterically significant, nonhydridic ancillary ligation.

AB - The adsorption of organoactinide complexes on dehydroxylated alumina (DA) yields coordinatively unsaturated, highly active catalysts for several demanding chemical transformations. Thus, in the case of Th(η3-allyl)4 supported on dehydroxylated γ-alumina (DA), facile arene hydrogenation and alkane activation processes can be effected in slurry reactions at 90°C and PH2 = 30-180 psi. Benzene reduction occurs at a turnover frequency of ≈ 25000 h-1 per active site and cyclohexane CH exchange with D2 at ≈ 1300 h-1 per active site. Active site characterization using D2O poisoning, hydrogenolysis, and CH3Cl dosing indicates ≤ 8 ± 1 % of the Th surface sites are catalytically significant. EPR and XPS spectroscopy provide no evidence for Th oxidation states less than +4. The mechanisms for the above processes are discussed in terms of electrophilic "four-center" activation processes in which the active sites appear to bear sterically significant, nonhydridic ancillary ligation.

KW - alkane activation

KW - allyl complexes

KW - arenes

KW - heterogeneous catalysis

KW - hydrogenation

KW - thorium

UR - http://www.scopus.com/inward/record.url?scp=0028762326&partnerID=8YFLogxK

U2 - 10.1016/0304-5102(93)E0210-8

DO - 10.1016/0304-5102(93)E0210-8

M3 - 文章

AN - SCOPUS:0028762326

SN - 0304-5102

VL - 86

SP - 23

EP - 50

JO - Journal of Molecular Catalysis

JF - Journal of Molecular Catalysis

IS - 1-3

ER -