Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published February 21, 2002 | public
Journal Article

Heterogeneous Inhibition of Homogeneous Reactions: Karstedt Catalyzed Hydrosilylation


The Karstedt-catalyzed hydrosilylation reaction used in curing of silicone release coatings was investigated using first-principle quantum mechanical techniques (density functional theory) as well as semiempirical methods to estimate solubility parameters. The results we obtain for the catalytic cycle indicate, in agreement with experimental results, that hydrosilylation occurs easily at room temperature. The detailed mechanism we suggest contains the key features of the models previously proposed in the literature by Lewis and Chalk−Harrod and adds quantitative estimates of reaction energies and barriers. On the basis of the energy profile for the catalytic cycle in the presence of inhibitor molecules and on solubility parameters for the species involved in the reaction, we conclude that the role of the inhibitors we considered is to phase-separate the catalyst from the substrate. The reaction is thus quenched by introducing a microscopic second phase that interferes with the homogeneous reaction.

Additional Information

© 2002 American Chemical Society. Received: July 26, 2001; In Final Form: November 26, 2001. Publication Date (Web): January 30, 2002. This research is supported by grants from NPTO (DoE-FETC) and with funding from NSF (MRI and CHE 95-22179). The facilities of the MSC are also supported by grants from DoE ASCI ASAP, ARO-MURI, BP Amoco, Chevron Corp., NASA, Beckman Institute, Seiko-Epson, Exxon, Asahi Chemical, Avery-Dennison, Dow, and 3M. We thank Carl J. Bilgrien at Dow-Corning. We further thank Avery-Dennison for financial support.

Additional details

September 28, 2023
October 24, 2023