Highly efficient procedure for the synthesis of biodiesel from soybean oil using chloroaluminate ionic liquid as catalyst

Use of ionic liquids in biodiesel production: a review

“…There are reports in the literature describing the alcoholysis of vegetable oils or animal fats by a variety of technological routes using several catalysts such as inorganic acids (Dupont et al, 2009;Liang et al, 2009;Zheng et al, 2006), inorganic bases (Dupont et al, 2009;Liang et al, 2009;Vicente et al, 2004) and enzymes (Gamba et al, 2008;Iso et al, 2001;Ranganathan et al, 2008), as discussed below. Depending on the catalyst chosen for the conversion of vegetable oils and animal fats to biodiesel, there are certain peculiarities associated with these reactions.…”

“…As disadvantages, the acid catalysis requires the use of large amounts of alcohol in order to obtain biodiesel in satisfactory yields, applying molar ratios of alcohol:oil of 30-150:1. Additionally, acid catalysts such as sulfuric acid catalyze the transesterification of triglycerides slowly even when refluxing with methanol, leading to long reaction times such as 48 to 96 hours (Liang et al, 2009). Finally, there is the risk of corrosion of the equipment used due to the high acidity of those catalysts.…”

“…Another disadvantage of this method is the water generated during the reaction of hydroxide ion with the alcohol used, even when water-free reagents are used in the process, leading to the occurrence of saponification. Moreover, the removal of the homogeneous catalysts after the reaction is technically difficult and a large amount of residual wastewater is produced due to separation and purification of products and catalyst (Liang et al, 2009). …”

“…A successful example of the use of chlorometallate ionic liquids was published by Liang et al (2009), reporting the synthesis of biodiesel from soybean oil. The catalyst triethylammonium chloroaluminate ([Et 3 NH]Cl/AlCl 3 ) with an AlCl 3 mole fraction of 0.7 showed 98.5% conversion of soybean oil after 9 hours of reaction at 70°C with a methanol:oil ratio of 12:1.…”

One-Step Production of Biodiesel from Waste Cooking Oil Catalysed by So₃H-Functionalized Quaternary Ammonium Ionic Liquid

“…ILs have attracted much interest as clean and alternative catalysts for biodiesel synthesis during the last decade. The production of biodiesel resulted in a higher yield in the presence of chloroaluminate IL as catalyst 13 . The dicationic ILs also give a superior catalytic performance for biodiesel synthesis 14,15 .…”