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Kinetics and thermodynamics of synthesis of palm oil-based trimethylolpropane triester using microwave irradiation
Journal of Saudi Chemical Society ( IF 5.8 ) Pub Date : 2020-06-03 , DOI: 10.1016/j.jscs.2020.05.006
Nur Atiqah Mohamad Aziz , Hamidah Abd Hamid , Robiah Yunus , Zulkifly Abbas , Rozita Omar , Umer Rashid , Azhari Muhammad Syam

Enhancement of reaction performance utilizing microwave irradiation has drawn so much interest due to its shorter reaction time and low catalyst loading. These advantages are particularly significant from kinetics and thermodynamics perspectives. This study aimed to investigate the kinetics and thermodynamics of microwave-assisted transesterification of palm oil-based methyl ester into biolubricant. The transesterification reaction of palm oil methyl ester (PME) and trimethylolpropane (TMP) was conducted at 110–130 °C for 90 min under vacuum condition. Sodium methoxide was employed as the catalyst at 0.6 wt% of reactants fixed at molar ratio of 4:1 (PME: TMP). The experimental data were fitted with the second-order reversible reaction kinetics mechanisms. The data were solved via Runge-Kutta 4,5 order using MATLAB software. Analysis on the data revealed that the reaction rate constants at temperatures of 110–140 ℃ were in the range of 0.01–0.63 [(w/w)(min)]−1, with standard errors of 0.0026–0.0228 within 99.99% prediction interval. Microwave-assisted reaction obtained 17.0 kcal/mol of activation energy. This method reduced activation energy by 49% as compared to the conventional heating. Activation energy and time-periodic energy assessment showed that the reaction was endothermic. The reaction at 130 °C is the easiest to activate. The positive Gibbs free energy (ΔG > 0) found using Eyring-Polanyi equation indicated that the transesterification was non-spontaneous and endergonic.



中文翻译:

微波辐射合成棕榈油基三羟甲基丙烷三酯的动力学和热力学

利用微波辐照提高反应性能引起了人们的极大兴趣,因为其反应时间更短且催化剂的负载量较低。从动力学和热力学的角度来看,这些优点特别重要。这项研究旨在调查动力学和热力学的微波辅助的棕榈油基甲酯酯交换为生物润滑剂。棕榈油甲酯(PME)和三羟甲基丙烷(TMP)的酯交换反应在110-130°C的真空条件下进行90分钟。使用甲醇钠作为催化剂,反应物的重量百分比固定为4:1(PME:TMP),固定比例为0.6%。实验数据符合二阶可逆反应动力学机理。数据使用MATLAB软件通过Runge-Kutta 4,5订单进行求解。-1,在99.99%预测间隔内的标准误差为0.0026-0.0228。微波辅助反应获得的活化能为17.0 kcal / mol。与常规加热相比,该方法将活化能降低了49%。活化能和时间周期能量评估表明反应是吸热的。在130°C的反应最容易活化。使用Eyring-Polanyi方程发现的正Gibbs自由能(ΔG> 0)表明酯交换反应是非自发的和正离子的。

更新日期:2020-06-03
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