介孔碳基固体酸催化剂与油脂降酸的构效关系研究
发布时间：2019-03-28 12:52
【摘要】：介孔结构凭借其高的比表面、孔径大、孔壁组成以及介观结构多样等特点,被广泛应用于环境、医疗和能源等领域。已有的研究对材料的形貌与孔结构控制不够,合成的方法缺乏改进。常见的介孔碳经过磺化后作为固体酸催化剂,用于酯化反应的研究虽有报道,但固体酸催化剂与油脂降酸的构效关系研究鲜有报道。本文利用PF为原料,通过EISA法合成了介孔碳材料,得到了催化剂的比表面积、孔道有序性和孔容大小等数据,最后深入探讨了介孔材料与油脂降酸构效关系,不仅可以丰富介孔碳材料的内容,也对促进气相酯化降酸反应的进行有着重要的意义。获得主要研究结论:(1)利用一步法合成了不同碳源催化剂,其中厌氧发酵残留物固体酸催化性能最佳。在合成温度110℃、合成时间120min和硫酸质量浓度为30%的条件下,厌氧发酵残留物固体酸催化性能较优,酯化率可达65.37%。表征得到,多孔碳基固体催化剂为不定形碳结构。同时随磺化时间的增加石墨化以及磺化程度越来越好,厌氧发酵残留物固体酸孔道以微孔为主。当醇油摩尔比为8:1、催化剂用量为4wt%、体系温度80℃和反应2h后,厌氧发酵残留物固体酸酯化降酸的转化率达到了 76.32%。(2)分别考虑合成方法、模板剂、碳前驱体对合成的一系列样品有序性和孔类型的影响。表征结果表明:F127或F127:P123=2:1为模版,PF为前驱体,EISA法得到了有序介孔碳基固体酸催化剂,且孔道有序性最好。酯化反应条件:反应温度110℃、催化剂用量3wt%、反应时间90min。样品F-E-PF-S酯化降酸效果最佳,转化率可达到94.20%,样品F-H-PF-S可达91.50%。F127/P123=2:1时催化剂酯化降酸效果优于单独使用F127,转化率达到95.10%。因此,最适合成条件:EISA为最适合成方法、酚醛树脂为前驱体。(3)预聚温度75℃催化剂有序性最佳,其比表面积为677.97m~2/g,对应的孔径2.0nm;随着预聚时间的增加催化剂有序性增强;随着升温速率的增加催化剂有序性降低;模版配比为2:1时催化剂有序性最好。(4)选择比表面积为677.97m~2/g的样品催化气相酯化降酸反应,得到的最佳条件为:催化剂用量3wt%、反应温度110℃、反应时间120min得到酯化降酸转化率为95.48%;与厌氧发酵残留物固体酸比较,介孔催化剂活性明显更优,120 min转化率可达到95.48%,厌氧发酵残留物固体酸转化率仅为76.31%。介孔孔道的增加有利于酯化降酸反应的进行。通过对介孔类催化剂构效关系进行分析,结果表明,催化剂的有序性对降酸反应的速率以及转化率均存在一定的影响;酯化转化率随催化剂的比表面积增加,呈上升趋势;催化剂孔径大小对酯化降酸转化率的影响规律性不太明显,后续有待继续研究。
[Abstract]:Mesoporous structures are widely used in environmental, medical and energy fields due to their high specific surface area, large pore size, pore wall composition and various mesoscopic structures. The previous studies have not controlled the morphology and pore structure of the materials, and the synthesis methods are lack of improvement. It has been reported that mesoporous carbon has been used as solid acid catalyst after sulfonation, but the structure-activity relationship between solid acid catalyst and fatty acid deacidification has been rarely reported. In this paper, mesoporous carbon materials were synthesized by EISA method using PF as raw material. The specific surface area, pore order and pore volume of the catalysts were obtained. Finally, the structure-activity relationship between mesoporous materials and fatty acids was discussed. It can not only enrich the content of mesoporous carbon materials, but also promote the esterification and reduction of acid in gas phase. The main conclusions are as follows: (1) the catalysts of different carbon sources were synthesized by one-step method, among which the solid acid catalyst of anaerobic fermentation residue was the best. Under the conditions of synthesis temperature 110 鈩，
本文编号：2448885
[Abstract]:Mesoporous structures are widely used in environmental, medical and energy fields due to their high specific surface area, large pore size, pore wall composition and various mesoscopic structures. The previous studies have not controlled the morphology and pore structure of the materials, and the synthesis methods are lack of improvement. It has been reported that mesoporous carbon has been used as solid acid catalyst after sulfonation, but the structure-activity relationship between solid acid catalyst and fatty acid deacidification has been rarely reported. In this paper, mesoporous carbon materials were synthesized by EISA method using PF as raw material. The specific surface area, pore order and pore volume of the catalysts were obtained. Finally, the structure-activity relationship between mesoporous materials and fatty acids was discussed. It can not only enrich the content of mesoporous carbon materials, but also promote the esterification and reduction of acid in gas phase. The main conclusions are as follows: (1) the catalysts of different carbon sources were synthesized by one-step method, among which the solid acid catalyst of anaerobic fermentation residue was the best. Under the conditions of synthesis temperature 110 鈩，
本文编号：2448885
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