ABSTRACT
Diesel fuels are characterized by cetane numbers, which are analogous to octane numbers for gasoline. The cetane value of a fuel is intimately linked to its chemical composition. The most successful, and commonly used cetane additive is 2-ethylhexyl nitrate (EHN). Di-tert -butyl peroxide is gaining acceptance as a cetane additive and rival to EHN. This chapter describes additives synthesized from fatty acid esters, which rival the performance of EHN while exhibiting a significantly lower nitrogen content. The industry has adopted "blending cetane numbers" (BCN's) as a method to rank improvers. BCN's are dramatically affected by such factors as concentration, chemical composition of base fuel, and the method of testing. Most vegetable oils are mixtures of different triglycerides of fatty acids. Plant oils differ from animal fats because the vegetable fatty acids are predominately unsaturated. The chapter focuses on oleic acid esters as models for the chemistry of vegetable triglycerides, because oleic acid is a major constituent of most vegetable oils.
