The activity and the selectivity of the vanadyl pyrophosphate catalyst in the heterogeneous oxidn. of C1-7 alkanes is compared. The comparison of the reactivities of the linear, branched and cyclic alkanes suggests that (i) in the mechanism of activation the driving force is the formation of the corresponding olefins and (ii) the rate detg. step is the contemporaneous removal of two H atoms by a concerted mechanism. In the C2-3 alkane oxidn. only corresponding olefins are formed. n-Butane selectively give maleic anhydride; n-pentane selectively forms maleic and phthalic anhydrides, together with smaller amts. of benzoic acid. In the oxidn. of the other alkanes, on the contrary, the principal product is maleic anhydride, but the selectivity decrease with increase of the carbon atom no. in the hydrocarbon. [on SciFinder(R)]
Functionalization of paraffinic hydrocarbons by heterogeneous vapor-phase oxidation. III. Conversion of the C1-C7 alkane series
CENTI, Gabriele;
1988-01-01
Abstract
The activity and the selectivity of the vanadyl pyrophosphate catalyst in the heterogeneous oxidn. of C1-7 alkanes is compared. The comparison of the reactivities of the linear, branched and cyclic alkanes suggests that (i) in the mechanism of activation the driving force is the formation of the corresponding olefins and (ii) the rate detg. step is the contemporaneous removal of two H atoms by a concerted mechanism. In the C2-3 alkane oxidn. only corresponding olefins are formed. n-Butane selectively give maleic anhydride; n-pentane selectively forms maleic and phthalic anhydrides, together with smaller amts. of benzoic acid. In the oxidn. of the other alkanes, on the contrary, the principal product is maleic anhydride, but the selectivity decrease with increase of the carbon atom no. in the hydrocarbon. [on SciFinder(R)]Pubblicazioni consigliate
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