Zhongguo youzhi (Sep 2023)
对甲苯磺酸催化合成季戊四醇异硬脂酸酯 工艺优化及其表征分析Synthesis process optimization and characterization of pentaerythritol isostearate catalyzed by p-toluenesulfonic acid
Abstract
为改善现有季戊四醇异硬脂酸酯生产工艺存在的反应时间长、反应温度高、效率低等问题，研究采用对甲苯磺酸催化季戊四醇与异硬脂酸酯化合成季戊四醇异硬脂酸酯。以异硬脂酸酯化率为考察指标，利用单因素实验和正交实验对酯化工艺条件进行优化，对酯化粗产物进行除酸提纯处理，并对粗产物进行红外光谱分析，对除酸提纯产物进行质谱分析、热重分析及性能指标测定。结果表明：最优的酯化反应工艺条件为反应时间5 h、反应温度140 ℃、催化剂用量1%（基于反应总投料质量）、异硬脂酸与季戊四醇物质的量比值4.3，在此条件下酯化率为99.27%，粗产物酸值（KOH）为13.26 mg/g。红外光谱结果表明此酯化反应合成了季戊四醇异硬脂酸酯，质谱鉴定结果显示主要合成产物为季戊四醇四异硬脂酸酯。经脱酸处理，产物的酸值（KOH）降为3.23 mg/g，与市售产品接近，热重分析及性能指标测定结果显示提纯产物具有优异的热稳定性，良好的黏温性能、优异的低温流动性及良好的安全性。优化的对甲苯磺酸催化合成季戊四醇异硬脂酸酯工艺具有能耗低、产物品质高的优点。 In order to improve the existing production process of pentaerythritol isostearate, which has the problems of long reaction time, high reaction temperature and low efficiency, the synthesis of pentaerythritol isostearate by esterification of pentaerythritol with isostearic acid catalyzed by p-toluenesulfonic acid was carried out.The esterification process conditions were optimized using single factor experiment and orthogonal experiment with esterification rate of isostearic acid as the index.The crude product of esterification was purified by deacidification, the crude product was analyzed by infrared spectroscopy, and the purified product was analyzed by mass spectrometry, thermogravimetric analysis, and its performance indexes were also determined.The results showed that the optimal process conditions were obtained as follows: reaction time 5 h, reaction temperature 140 ℃, dosage of catalyst 1%(based on the total mass of substrates), and the molar ratio value of isostearic acid to pentaerythritol 4.3. Under these conditions, the esterification rate was 99.27% and the acid value of the crude product was 13.26 mgKOH/g.The infrared spectroscopy results indicated that the esterification reaction synthesized pentaerythritol isostearate, and mass spectrometry identification results showed that the main synthesized product was pentaerythritol tetraisostearate. After deacidification, the acid value of the product was reduced to 3.23 mgKOH/g, which was close to that of the commercial product. The results of thermogravimetric analysis and the performance indexes showed that the purified product had excellent thermal stability, good viscosity-temperature properties, excellent low-temperature fluidity and good safety. The optimized process of synthesis of pentaerythritol isostearate catalyzed by p-toluenesulfonic acid had advantages of low energy consumption and high product quality.
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