Silica-Supported | An-Najah Staff

Silica-Supported Iridium-Phosphine Catalysts for the Reaction of the Silanes with Alcohols

Wed, 2010-04-21 14:32 — Hikmat S. Hilal, D.Sc.

Journal Title, Volume, Page:

Journal Of Organometallic Chemistry Volume 228, Issue 2, 23 March 1982, Pages 191-201

Year of Publication:

1982

Link:

http://www.sciencedirect.com/science/article/pii/S0022328X00870977

Authors:

H. S. Hilal

Department of Chemistry, The University of Manchester Institute of Science and Technology

Current Affiliation:

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine

[email protected]

J. Dwyer

Department of Chemistry, The University of Manchester Institute of Science and Technology

R. V. Parish

Department of Chemistry, The University of Manchester Institute of Science and Technology, Manchester, M60 1QD Great Britain

Preferred Abstract (Original):

Silica-supported iridium catalysts have been evaluated in the reactions of HSiR₃ (R  Et, OEt) and Me₃SiO[Si(H)(Me)O]_nSiMe₃ (PS1, n  1; PS50, n ∼ 50) with awide variety of primary alcohols. Catalysts obtained by reaction of IrCl(CO)[Ph₂P(CH₂)₂Si(OEt)₃]₂ with silica are rapidly deactivated in a manner similar to the related homogeneous systems. More active catalysts are obtinaed by treating the silica first with Ph₂P(CH₂)₂Si(OEt)₃ and then with [IrCl(C₈H₁₄)₂]₂. The order reactivity of the silanes is PS50 ⪢ HSi(OEt)₃ > HSiEt3 ⪢ PS1, and that of the alcohols reflects principally the bulk of the organic group. Kinetic analysis indicates two pathways involving iridium bound to the phosphine and directly to the silica. The ²⁹ Si{¹H} NMR spectra of PS50 and the product of its reaction with Ph(CH₂)₂OH are reported.

A New Silica-Supported Platinum-Amine Catalyst for The Reaction of Silanes with Alcohols

Wed, 2010-04-21 14:32 — Hikmat S. Hilal, D.Sc.

Journal Title, Volume, Page:

Journal of Molecular Catalysis Volume 61, Issue 1, 15 July 1990, Pages 1-17

Year of Publication:

1990

Link:

http://www.sciencedirect.com/science/article/pii/030451029085188N

Authors:

H.S. Hilal

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine

Current Affiliation:

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine

[email protected]

A. Rabah

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine

I.S. Khatib

Department of Chemistry, An-Najah N. University, Nablus, PO Box 7, West Bank, Palestine

A.F. Schreiner

Department of Chemistry, North Carolina State University Box 8204, Raleigh, N.C. 27695-8204 U.S.A

Preferred Abstract (Original):

A supported platinum catalyst has been prepared and evaluated for the reactions of HSiR₃ (R = Et, OEt) and Me₃SiOSi(H)(Me)OSiMe₃ with alcohols ROH (R = Me, Et, n-Pr, i-Pr, t-Bu). The supporting surface was prepared by a condensation reaction of (EtO)₄Si with the ligand (RO)₃SiCH₂CH₂CH₂NH₂ in the presence of water. The catalyst partially retains its activity on recovery after three different reaction times. Moreover, the catalytic activity is highly reproducible within the same batch, and among different prepared batches. Variation of the types of silanes and of the alcohols affects the rate of the reaction. The reaction is first order with respect to the catalyst and the silane. A first-order reaction with respect to alcohol is observed at low concentrations, whereas at higher concentrations the rate is independent of the alcohol concentration. There is no evidence of a reaction between the supported amine ligand and the silane. The effects of temperature, solvent polarity and added ligands are also reported.