Potential hazard in hydrosilylation of D4Vi with D4H

Slawomir Rubinsztajn; Larry N. Lewis; Judith Stein; Michael J. Michalczyk
General Electric Corporate R&D, Schenectady, N.Y.; DuPont Central R&D, Wilmington, Del.

Chemical & Engineering News (25 Apr 1994) Vol. 72, No. 17, pp. 4.

We would like to comment on a recent communication by M. J. Michalczyk, W. E. Farneth, and A. J. Vega in Chemistry of Materials [5, 1687 (1993)]. In this paper, one of us describes a synthesis of highly cross-linked carbosiloxane glasses by hydrosilylation of [(Me(Vi)SiO)4] (D4Vi) and [(Me(H)SiO)4] (D4H) according to the procedure described in the General Electric patents by H. F. Lamoreaux. In all preparations of these glasses at DuPont, no safety problems or unusual hazards were observed in carrying out the hydrosilylation reaction D4Vi with D4H.

However, recent communication between us has brought to our attention some potential safety hazards associated with this synthesis. In particular, researchers at General Electric have sometimes observed uncontrollable exotherms or explosions during the hydrosilylation of D4Vi with D4H. Exothermic reactions were also observed when an excess of D4H was used. At DuPont, we have observed similar exotherms during the hydrosilylation of tetravinylsilane with D4H. Because of the potential safety problem associated with this and other related syntheses, we now suggest caution be used when carrying out the hydrosilylation reaction of D4Vi with D4H and recommend that hydrosilylations using monomers with low flash points be carried out behind a safety shield at the smallest possible scale with a low level (below 20 ppm) of platinum. The typical commercial product lines that employ platinum cures have no hazards.

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