Nonmolecular Nature of Nitric-Oxide-Inhibited Thermal Decomposition of n-Butane

The thermal decomposition of most organic molecules is generally accepted to occur at least in part via a free radical chain process. Since Hinshelwood and Staveley (1) discovered that small additions of nitric oxide reduced the rate of thermal decomposition, there has been much controversy (2) concerning the nature of the “residual” reaction remaining after further additions of inhibitor produce no further decrease in rate. Jach, Stubbs, and Hinshelwood (3) have shown this limiting rate to be independent of the inhibitor used and attribute this residual reaction to a nonchain molecular process in which the parent molecule breaks up, in a single step, into stable products.