Parameters affecting oleochemical production from waste bleaching earth via alcoholysis

The edible oil industry is one of the largest industries in the world. In the edible oil refining process, large amounts of waste are discarded every day. Evaluation of these wastes is vital for environmental issues. Most of this waste is due to the bleaching process in which bleaching earths are largely used. Due to its high adsorption capacity, bleaching earth adsorbs oil nearly 40% of its weight. In order to evaluate this waste for oleochemical production, alcoholysis reactions were investigated. Parameters affecting the reaction, such as catalyst type and amount, alcohol type, alcohol:oil molar ratio and temperature, were investigated. The reactions were conducted in the presence of different catalysts such as NaOH, NaOCH₃ and homogeneous alkali polymeric gel catalyst (HAPJEK) and performed at a temperature range of 60–78°C and in the presence of a catalyst (1–2% based on oil weight) at alcohol:oil molar ratios of 5:1–7:1. Based on optimisation by response surface methodology (RSM), the critical synthesis conditions for 210 min reaction time with a maximum of 85.8% methyl ester content were determined as temperature: 68.4°C, catalyst amount 1.5% based on oil weight and methanol/oil molar ratio: 6.4.