银改性磷钨酸催化制备生物柴油工艺研究

doi:10.11938/cjmr20192760

摘要/Abstract

摘要： 本文以硝酸银和磷钨酸为原料制备了系列银改性磷钨酸催化剂Ag_xH_3-xPW₁₂O₄₀（x=1、2、3，x表示AgNO₃与磷钨酸的物质的量之比），并利用傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、热重量分析-导数热重量分析（TGA-DTG）和固体核磁共振结合探针分子（³¹P-TMPO MAS-NMR）技术对它们的结构、稳定性及酸性进行了表征；同时考察了甲醇/大豆油的物质的量之比、催化剂用量、反应温度和反应时间等因素对磷钨酸银催化酯交换反应的影响.研究结果表明，Ag₂HPW₁₂O₄₀催化剂具有最好的催化酯交换反应活性和重复使用性能，其结构中的Brønsted酸中心与Lewis酸中心之间的协同效应是使其具有高催化性能的原因.以Ag₂HPW₁₂O₄₀为催化剂，在甲醇/大豆油的物质的量之比为32/1、催化剂用量为6 wt.%、反应温度为150℃、反应时间为20 h条件下，生物柴油产率可达96.4%.

关键词: 磷钨酸, 酯交换反应, 生物柴油, 催化技术

Abstract: A series of silver-modified phosphotungstic acid catalysts Ag_xH_3-xPW₁₂O₄₀ (x=1, 2, 3) were synthesized by incorporating silver nitrate into phosphotungstic acid. The structure, stability and acidity of the catalysts synthesized were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis-derivative thermogravimetric analysis (TGA-DTG) and ³¹P-TMPO magic-angle spinning nuclear magnetic resonance (³¹P-TMPO MAS-NMR) spectroscopy. The effects of various reaction parameters, such as methanol/oil molar ratio, amount of catalyst, reaction time, and reaction temperature on the catalytic transesterification of soybean oil and methanol with Ag₂HPW₁₂O₄₀ were investigated. The results demonstrated that Ag₂HPW₁₂O₄₀ had the best catalytic activity, superior biodiesel yield and excellent durability. The high catalytic activity of the catalyst was attributed to Brønsted-Lewis acid synergy. With 6 wt.% Ag₂HPW₁₂O₄₀ catalyst, the yield of biodiesel reached 96.4% with a methanol/soybean oil molar ratio of 32/1, a reaction temperature of 150℃ and a reaction time of 20 h.

Key words: phosphotungstic acid, transesterification reaction, biodiesel, catalyst

中图分类号:

TQ517.2

徐超, 蔡哲, 王晴, 梅星雨, 周祐昇, 徐艺洺, 端木佳辉, 汪思田, 韩晓祥. 银改性磷钨酸催化制备生物柴油工艺研究[J]. 波谱学杂志, 2020, 37(1): 86-94.

XU Chao, CAI Zhe, WANG Qing, MEI Xing-yu, ZHOU You-sheng, XU Yi-ming, DUAN-MU Jia-hui, WANG Si-tian, HAN Xiao-xiang. Preparation of Biodiesel Using Silver-Modified Phosphotungstic Acid as Catalyst[J]. Chinese Journal of Magnetic Resonance, 2020, 37(1): 86-94.

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