Chemical Kinetics of Cetane Number Improving Agents

INTRODUCTION The increasing demand for diesel fuels has resulted in the use of greater percentage of cracked distillates having poor ignition properties. The ignition properties of diesel fuels can be rated in terms of their cetane number and diesel fuels having low cetane number may have poor ignition properties such as diesel knock, difficulties to start engines in the cold weather and so on. Such diesel fuels need cetane number improving agents. In the 1940s and 1950s alkyl nitrates, alkyl nitrites and organic peroxides were found to be effective cetane number improving additives ( I ) . Our recent study suggests that free radicals produced from thermal decomposition just before ignition should have an important role to improve their ignition properties (2) . However no studies on the reaction mechanism for improving effect of these additives have been attempted because of complex nature of spontaneous ignition reaction of hydrocarbons. In order to clarify the reaction mechanism for improving effects of cetane number improving agents. We here have attempted to simulate the spontaneous ignition of n-butane as a model compound in the presence of alkyl nitrites as cetane number improving agents.