Transesterification of Waste Oils to Biodiesel Using Br鴑sted Acid Ionic Liquid as Catalyst

摘要

Natural fats are converted into biodiesel in typical process of methanolysis. This process has attracted considerable attention during the past decade. As a renewable, biodegradable, non-taic fuels and an alternative to fossil fuels, biodiesel must be technically feasible, economically competitive, environmentally acceptable, and readily available. However, due to the higher raw material cost, biodiesel is difficult to compete with petroleum diesel. Therefore, low-cost feedstocks or waste oils, such as non-edible oils and waste frying oils, can be used as raw materials. In this paper, Br.nsted acid ionic liquids were employed for the preparation of biodiesel using waste oil as the feedstock. It was found that IL 1 -(3-sulfonic acid)propyl-3-methylimidazole hydrosulfate-[HO3S-(CH2)3-mim]HSO4 was an efficient catalyst for the reaction. The influences of reaction conditions, such as dosage of catalyst, reaction temperature and time, were examined. The optimum conditions for the reaction were obtained as follows: n(oil):n(methanol) 1:10, oil 15 g, ionic liquid 2.0 g, reaction temperature 120 oC and reaction time 4 h. Under the above condition, the yield of biodiesel was more than 95%. The reusability of the ionic liquid was also investigated. When the ionic liquid was repeatedly used for five times, the yield of product was still more than 93%. Therefore, an efficient and environmentally friendly catalyst was provided for the synthesis of biodiesel from waste oils.