Yan Jingsen, Wang Zeqing, E Yongsheng, He Fengwei, Zhang Danfeng, Wu Qingyin
School of Biomedical & Chemical Engineering, Liaoning Institute of Science and Technology Benxi 117004 Liaoning P. R. China
Department of Chemistry, Zhejiang University Hangzhou 310027 P. R. China.
RSC Adv. 2019 Mar 14;9(15):8404-8410. doi: 10.1039/c8ra10659b. eCollection 2019 Mar 12.
A series of polyoxometalate-based ionic liquid (POM-IL) catalysts with functional sulfonic acid groups, [TEAPS] PW V O ( = 1, 2, 3) were synthesized and characterized by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectrophotometry (FT-IR), UV-Vis spectrophotometry (UV), potentiometric titration and thermogravimetry-differential scanning calorimetry (TG-DSC). The catalytic ability and reusability of the POM-IL catalysts were evaluated on esterification of chloroacetic acid and -amyl alcohol. The optimum reaction conditions, 0.2 g of the catalyst amount, 10 mL of water carrier, 140 °C of reaction temperature, and 1.2/1 of the molar ratio of alcohol/acid, were obtained by an orthogonal test. [TEAPS]PWVO was found to be the best active catalyst with an esterification rate of 98.75% and could be reused five times without significant decrease in activity. The ionic liquid acted as a temperature-responsive catalyst, forming a homogeneous mixture with the reactants at reaction temperature, and could be precipitated and separated from products when the reaction ends at ambient temperature. Therefore, an environmentally friendly and highly efficient approach for the synthesis of chloroacetates is provided.
合成了一系列具有功能磺酸基团的基于多金属氧酸盐的离子液体（POM-IL）催化剂[TEAPS]PWVO（=1,2,3），并通过核磁共振光谱（NMR）、傅里叶变换红外光谱法（FT-IR）、紫外可见分光光度法（UV）、电位滴定法和热重-差示扫描量热法（TG-DSC）对其进行了表征。在氯乙酸与正戊醇的酯化反应中评估了POM-IL催化剂的催化能力和可重复使用性。通过正交试验获得了最佳反应条件：催化剂用量0.2 g、水载体10 mL、反应温度140℃以及醇/酸摩尔比1.2/1。发现[TEAPS]PWVO是最佳活性催化剂，酯化率为98.75%，并且可以重复使用五次而活性没有明显下降。该离子液体作为一种温度响应型催化剂，在反应温度下与反应物形成均匀混合物，当反应在室温下结束时可以沉淀并与产物分离。因此，提供了一种环境友好且高效的合成氯乙酸酯的方法。
