Dehydrogenative mechanistic considerations

In conclusion, the Box-Wilson composite design is a convenient method for modeling of product yield as a function of reaction parameters (independent variables) especially when their number exceeds 2. In the dehydrogenation of n-decane, effect of reaction parameters on monoene selectivity / yield and n-decane conversion are represented satisfactorily by full II degree polynomial equations. The canonical form of the equations in the present study is indicative of an approximately stationary ridged system, with the reaction parameters close to center of design being optimum for monoene yield at conversion levels of 12 - 13 %. The polynomial equations were found to be consistent, with mechanistic considerations. 

Considerable interest in the subject of C-H bond activation at transition-metal centers has developed in the past several years (2), stimulated by the observation that even saturated hydrocarbons can react with little or no activation energy under appropriate conditions. Interestingly, gas phase studies of the reactions of saturated hydrocarbons at transition-metal centers were reported as early as 1973 (3). More recently, ion cyclotron resonance and ion beam experiments have provided many examples of the activation of both C-H and C-C bonds of alkanes by transition-metal ions in the gas phase (4). These gas phase studies have provided a plethora of highly speculative reaction mechanisms. Conventional mechanistic probes, such as isotopic labeling, have served mainly to indicate the complexity of "simple" processes such as the dehydrogenation of alkanes (5). More sophisticated techniques, such as multiphoton infrared laser activation (6) and the determination of kinetic energy release distributions (7), have revealed important features of the potential energy surfaces associated with the reactions of small molecules at transition metal centers. 

The consideration of rates and mechanistic aspects of reactions such as hydrogenolysis, dehydrogenation, and isomerization provides a basis for interpreting selectivity data on bimetallic catalysts. 

---