ABSTRACT
Activation of C-H bonds during the combustion of saturated
hydrocarbons is an extremely important step for the generation of
power and heat. The hardest step is the activation of the first C-H
bond. Once the first bond breaks, the consecutive reactions proceed
more easily. Therefore, understanding the C-H bond activation in
saturated hydrocarbons is important. It also improves the approach
to assessing the effect of catalytic and reaction parameters on the
rate and the efficiency of catalytic combustion. Many different types
of catalysts are capable of oxidizing saturated hydrocarbons with
varying efficiency. Among the saturated hydrocarbons methane is
the most difficult compound to activate, higher hydrocarbons are
easier to activate, and the hydrocarbons from C2 to C4 exhibit
an intermediate difficulty for bond activation. The difference in
activity of hydrocarbons can partly be related with the adsorption
of hydrocarbons on oxide surfaces, which is considered as a prior
condition to combustion. Adsorption of a larger molecule in a
predissociative state is more efficient than for a smaller molecule.
C-H bond activation requires harsher conditions, particularly higher
temperature. The optimal temperature for selective oxidation of an
alkane C-H bond until 2002 was shown by Thomas et al. [1-3]
to be 100◦C using transition metal ion-substituted molecular sieve catalysts, followed by use of gold catalysts by Xu et al. [4] in 2005 at
70◦C.
