The synthesis of glycerol monolaurate (GML) by the esterification of glycerol (GL) with lauric acid (LA) over a series of propyl sulfonic acid-functionalized ionic liquids (SAFILs)-modified silicotungstic acid (STA; H₄SiW₁₂O₄₀) composite catalysts has been investigated. The synthesized organic–inorganic hybrid catalysts were characterized by different physicochemical techniques. In particular, their acidic properties were studied by solid-state ³¹P magic angle spinning (MAS) NMR spectroscopy by using adsorbed trimethylphosphine oxide (TMPO) as a probe. The effects of key reaction parameters, such as glycerol/lauric acid molar ratio, amount of catalyst, reaction time, and reaction temperature on LA conversion and GML product yield were elucidated and optimized with response surface methodology (RSM). The N,N-dimethyl(benzyl)ammonium propyl sulfobetaine (DMBPS)-modified STA [DMBPSH]H₃SiW₁₂O₄₀ exhibited the optimal catalytic activity and was exploited for process optimization. A highest GML yield of 79.1 % was achieved with the optimized reaction conditions. The high catalytic activity of these hybrid catalysts were attributed to strong acidity, low transport resistance, and their “pseudoliquid” characteristics. A kinetic study was made based on a second-order irreversible model of the esterification reaction, which resulted in an activation energy of 39.49 kJ mol⁻¹ for [DMBPSH]H₃SiW₁₂O₄₀ under optimized reaction conditions.

中文翻译：

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离子液体-硅钨酸复合物是甘油与月桂酸将甘油选择性酯化为单月桂酸酯的高效可回收催化剂

在一系列经丙磺酸官能化的离子液体（SAFILs）改性的硅钨酸（STA; H ₄ SiW ₁₂ O ₄₀）上将甘油（GL）与月桂酸（LA）酯化来合成甘油单月桂酸酯（GML ）已经研究了复合催化剂。合成的有机-无机杂化催化剂通过不同的物理化学技术进行表征。尤其是，通过固态³¹研究了它们的酸性通过使用吸附的三甲基氧化膦（TMPO）作为探针进行P幻角旋转（MAS）NMR光谱分析。阐明了关键反应参数，如甘油/月桂酸摩尔比，催化剂用量，反应时间和反应温度对LA转化率和GML产物收率的影响，并通过响应面法（RSM）进行了优化。的Ñ，ñ -二甲基（苄基）铵丙基磺基甜菜碱（DMBPS）改性STA [DMBPSH 1 H ₃硅钨酸₁₂ Ô ₄₀具有最佳的催化活性，可用于工艺优化。在优化的反应条件下，GML的最高收率为79.1％。这些杂化催化剂的高催化活性归因于强酸度，低传输阻力及其“伪液体”特性。基于酯化反应的二级不可逆模型进行了动力学研究，得出在最佳反应条件下[DMBPSH] H ₃ SiW ₁₂ O ₄₀的活化能为39.49 kJ mol ^-1。