PRIMARY SELECTIVITY IN THE ACTIVATION OF THE CARBON-HYDROGEN BONDS OFPROPANE BY SILICA-SUPPORTED ZIRCONIUM HYDRIDE

The stoichiometric reaction between propane and(=SiO)(3)ZrH leads to t he formation of a mixture of (= SiO)(3)ZrCH(CH3)(2) and (= SiO)(3)ZrCH 2CH2CH3. The relative amounts of each complex resultant from the react ion was determined by (a) reaction of (= SiO)(3)ZrC3H7 with D2O to pro duce quantitatively a mixture of CH3CH3CH2D and CH3CHDCH3 which in tur n were discriminated by mass spectroscopy, and (b) reaction of(= SiO)( 3)ZrC3H7 with O-2 followed by HCl yielding 1-propanol and 2-propanol i n low yield. Each of these methods indicated that (= SiO)(3)ZrCH2CH2CH 3 was the major product of propane activation. The catalytic deuterati on of propane by deuterium at room temperature catalysed by (= SiO)(3) ZrH showed that the primary C-H bonds of propane reacted seven times f aster than the secondary C-H bonds. A mechanism of degenerate carbon-h ydrogen bond activation is invoked for the latter reaction.