SYNTHESIS AND CHARACTERIZATION OF FATTY ACID METHYL ESTER MIXTURES DERIVED FROM ACORN KERNEL OIL

Abstract

Biodiesel fuels are produced via transesterification of a triacylglycerol (TAG, e.g. vegetable oil, waste cooking oil, or animal fats) with a short-chain alkyl alcohol in the presence of a suitable catalyst. Alternative TAG sources, ones not derived from plants used as human food sources, have been of particular recent interest. In this work, the oil extracted from the endosperm of acorns, acorn kernel oil (AKO), was used as an alternative TAG source for the synthesis of biodiesel fuels. Acorns were collected from various species of oak trees (Quercus spp.) in the city of Nacogdoches, Texas. AKO was extracted from the acorn endosperm. The AKO was then subjected to acid-catalyzed and base-catalyzed transesterification with methanol and ethanol to produce acorn kernel oil methyl esters (AKOME) and acorn kernel oil ethyl esters (AKOEE) respectively. Concentrated H2SO4 was used as the acid catalyst and K2CO3 was used as the base catalyst. The effect of using a room temperature ionic liquid on percentage conversion for base-catalyzed transesterification was also investigated. Product mixtures were characterized using 1H-NMR spectroscopy. The NMR data were used to confirm the presence of transesterified products as well as to quantify the percentage conversion for the reaction. Percent conversion results ranged from 96 to 98% for AKOME products and 96 to 97% for AKOEE products.