This study introduces a temperature swing method for simultaneously producing biodiesel and ethyl levulinate through in-situ transesterification of spent coffee grounds. Effects of temperature and the amounts of catalyst and ethanol were investigated and it was found that the temperature predominantly affects the yield. Response surface methodology was employed to find the optimal conditions for maximizing biodiesel and ethyl levulinate yield. The highest biodiesel yield of 14.91±0.83 wt% was found at 140 °C, while the highest ethyl levulinate yield of 3.29±0.15 wt% was found at 160 °C. The maximum ethyl levulinate yield occurs at higher temperature than biodiesel due to decomposition of cellulose to produce ethyl levulinate, while the biodiesel yield decreases at elevated temperature due to unwanted humin formation. The proposed swing operation of the optimal temperature from 160 to 140 °C gives the highest yield of 15.02 wt% biodiesel and 2.76 wt% ethyl levulinate in the single-pot process.

本研究介绍了一种通过对废咖啡渣进行原位酯交换同时生产生物柴油和乙酰丙酸乙酯的变温方法。研究了温度以及催化剂和乙醇用量的影响，发现温度主要影响收率。响应面法用于寻找最大化生物柴油和乙酰丙酸乙酯产量的最佳条件。在 140 °C 时发现最高的生物柴油产率为 14.91±0.83 wt%，而在 160 °C 时发现最高的乙酰丙酸乙酯产率为 3.29±0.15 wt%。由于纤维素分解产生乙酰丙酸乙酯，乙酰丙酸乙酯的最大产率在高于生物柴油的温度下发生，而生物柴油的产率在升高的温度下由于不需要的腐殖质形成而降低。