Heterogeneous organosilicon compounds

Consecutive reactions of silyl and hydrogen radicals with other molecules can only occur if reactivity and lifetime of these radicals are sufficient to enable these successive reactions to predominate over. the further decomposition of the radicals to Si and H2. Such a reaction occurs between SiH4 and hydrocarbons above the decomposition temperature of SiH4, and results in the formation of heterogeneous organosilicon compounds. Saturated and unsaturated hydrocarbons react with SiH4... 

The silica-supported heterogeneous rhodium catalysts 1-5 were then tested in the conversion of organosilicon compounds, that is in the hydrosilylation of olefins with HSi(OEt)3 [36c,d, 37], heptamethyltrisiloxane and polyhydrosiloxane ]36a, 36c-e, 38]. 

The B coefficient corresponds to the logarithm of the rate constant at Tis, i-e. to the reaction proceeding on the pseudo-homogeneous surface. It is likely, that Tis and B constants may be useful characteristics of heterogeneous surface active sites reactivity towards a test gas reactant. For example, as it follows from Table 5, Tis value increases with enhancement of the chemisorption activation energy for interaction of organosilicon compounds with the free surface of pyrogenic parent and mixed oxides. 

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