The Reaction Between Methane and Hydroxyl Radical

A slightly more complicated example, yet one which is useful to illustrate a problem which can occur when analyzing isotope effects is the reaction between hydroxyl radical and methane  

Ideally, comparison of the rate constant for Equation 10.9 with that for the reaction involving mono-deuteromethane  

In reaction (10.11) the deuterium isotope effect is a secondary isotope effect, that is one in which the bonding to the isotopically substituted atom is not broken or formed during the course of the reaction. Secondary deuterium isotope effects are generally much smaller than primary ones. 

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