Levulinic acid, 4-oxopentanoic acid, is considered an attractive building block with widespread applications in various fields together with its derivatives. They can be used as lubricants, printing inks, corrosion inhibitors, products for personal care, and for drug delivery. In the present paper, attention was focused on the esterification of levulinic acid with ethanol promoted by a heterogeneous acid catalyst, in particular, an ion-exchange resin, namely, Amberlite IR120. The reaction was conducted in a continuous device by applying transient methods. This approach led to very attractive outcomes when compared to the traditional fixed bed reactor as water is removed continuously and the equilibrium is shifted, obtaining full conversion. A significant difference in performance is evident between the two operational modes. With a classical packed bed reactor, the maximum levulinic acid conversion was 31% at 363 K and a flow rate of 3.33 × 10^–8 m³/s, while by applying the transient method under the same conditions, the levulinic acid conversion rose to 94%. Kinetic tests were performed at different temperatures, varying the volumetric flow rate during the tests. Nearly complete conversion of levulinic acid was achieved in experiments conducted at temperatures of 313, 323, 343, and 363 K. Furthermore, high conversion, reaching 90%, was also attained at a lower temperature of 293 K. The experimental data were successfully interpreted with a mathematical model to retrieve kinetic and thermodynamic parameters. Finally, the fluid-dynamic characterization of the system demonstrated that the reactor worked with plug-flow behavior.

中文翻译：

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强化乙酰丙酸乙酯合成的瞬时方法


乙酰丙酸，4-氧代戊酸，被认为是一种有吸引力的基础材料，与其衍生物一起在各个领域都有广泛的应用。它们可用作润滑剂、印刷油墨、缓蚀剂、个人护理产品和药物输送。在本文中，重点关注了由非均相酸催化剂，特别是离子交换树脂，即 Amberlite IR120 促进的乙酰丙酸与乙醇的酯化反应。反应在连续装置中通过瞬时方法进行。与传统的固定床反应器相比，这种方法产生了非常有吸引力的结果，因为水被连续去除，平衡被改变，获得完全转化。两种操作模式之间的性能差异很明显。使用经典的填充床反应器，在 363 K 和 3.33 × 10^–8 m³/s 的流速下，乙酰丙酸转化率为 31%，而在相同条件下应用瞬态方法，乙酰丙酸转化率上升到 94%。动力学测试在不同温度下进行，测试过程中改变体积流速。在 313、323、343 和 363 K 的温度下进行的实验中实现了乙酰丙酸的几乎完全转化。此外，在 293 K 的较低温度下也实现了达到 90% 的高转化率。实验数据用数学模型成功解释，以检索动力学和热力学参数。最后，系统的流体动力学特性表明，反应器在活塞流行为下工作。