We have previously demonstrated that additives such as benzyl alcohol and the like successfully retard the formation of carbonaceous materials in jet fuels at temperatures in excess of 400-degrees-C. An understanding of the underlying mechanisms is important and could point the way to the design of superior additives. Here we report the results of thermal stressing studies performed on a model system consisting of dodecane/benzyl alcohol mixtures. Dodecane has been the subject of many prior studies and is a good representative model compound for jet fuel. Furthermore, deuterated compounds of both dodecane and benzyl alcohol are available and results obtained using these compounds were found to be particularly useful in rationalizing why benzyl alcohol acts as a thermal stabilizer in hydrocarbon mixtures at such high temperatures.