Synthesis and evaluation of alkyl nitrates from triglycerides as cetane improvers

Alkyl nitrate derivatives of soybean oil, castor oil, olive oil, and canola oil were synthesized and evaluated as cetane improvers for use in diesel fuel. Of several nitration methods evaluated, mixtures of nitric acid with acetic anhydride provided quality product while allowing nitration at ambient temperatures. Nitration using neat concentrated nitric acid was also effective in certain applications. Significant process development strides were made in the areas of reducing nitration costs, reducing risks associated with this nitration chemistry, and identifying processes that simultaneously address constraints on processing viscosities, product solubility, and waste minimization. Some of the products were effective cetane improvers, but their performance was not as consistent as that of the commercial product 2-ethylhexylnitrate.