含硅介孔材料固载酸性离子液体及其催化合成生物柴油

发布时间：2018-03-29 10:22

本文选题：介孔材料　切入点：离子液体　出处：《江南大学》2017年硕士论文

【摘要】：生物柴油是一种环境友好且可再生的生物质能源,可作为替代石油质能源的燃料,具有良好的市场前景。而生物柴油工业化生产的关键在于高效非均相催化剂的制备。目前催化合成生物柴油所用的非均相催化剂种类较多,其中固载型离子液体因绿色环保性受到广泛的关注。本研究旨在设计、制备系列酸性介孔材料,并进行酸性离子液体的固载,得到拥有双酸位特性的固载型离子液体催化剂;以大豆油和甲醇酯交换合成生物柴油的反应为探针,考察所制备的双酸位特性的固载型离子液体的催化性能。首先,采用一步水解共缩合并结合水热技术,制备了一系列酸性杂化介孔材料SO_4~(2-)-x/ZrO_2-SiO_2-y。利用傅里叶红外光谱、固体核磁(29Si MAS NMR)以及X射线光电子能谱对杂化材料的组成和结构进行表征,三者共同验证了杂化材料的合成;通过广角X射线衍射分析以及N2物理吸附测定,对杂化材料的孔结构性质进行表征,发现所合成杂化材料都具有优良的介孔结构;利用酸碱滴定法对杂化材料表面的酸量进行测定,结果表明,杂化材料表面的Br?nsted酸容量主要由其活性组分SO_4~(2-)的量决定。其次,采用表面嫁接法将酸性离子液体—磺酸功能化咪唑硫酸氢盐([Ps-im]HSO4)固载到杂化介孔材料SO_4~(2-)-x/ZrO_2-SiO_2-y上,制备了系列固载型离子液体SO_4~(2-)-x/ZrO_2-SiO_2-y-IL。该系列催化剂拥有优良的结构特性以及独特的双酸位性质,其催化活性不仅比均相催化剂高,更优于单酸性位的固载型离子液体SBA-15-IL。运用傅里叶红外光谱、X射线衍射、N2物理吸附、透射电镜和热重等表征手段,对催化剂的结构、组成进行分析。此外,还以SO_4~(2-)-1.2/ZrO_2-SiO_2-1.0-IL为例,对酯交换反应的工艺参数进行单因素优化,得到适宜的工艺为:140℃的反应温度,4 h的反应时间,30:1的醇油摩尔比以及5 wt%的催化剂用量(基于大豆油质量的百分比),在此条件下,所得生物柴油的收率超过96%;但在重复利用的过程中,催化剂的活性逐渐降低,其原因可能是由亲水性载体对甘油的吸附导致的。最后,为了增强杂化材料的疏水性,从而提高固载型离子液体的重复利用性,因此在杂化材料的合成过程中,采用有机硅((CH3CH2O)3Si-Et-Si(OCH2CH3)3,BTEE)取代无机硅(正硅酸四乙酯,TEOS),即对无机杂化材料进行有机改性,合成有机-无机杂化材料SO_4~(2-)/ZrO_2-SiO_2(Et),并进行不同离子液体用量的固载。采用傅里叶红外光谱、固体核磁、X射线光电子能谱、X射线衍射、透射电镜、N2物理吸附测试及热重等表征方法,对有机-无机杂化材料及其固载型离子液体的组成、孔洞结构、热稳定性和酸性位点类型等性质进行了分析;此外,还通过接触角测试仪对载体的疏水性改性效果进行了表征。以固载型离子液体为酯交换反应的催化剂,采用单因素和响应面分析法对反应工艺参数进行优化。结果表明:在离子液体固载量为2.50 mmol·g~(-1),催化剂用量(基于大豆油质量的百分比)为5.0 wt%,反应温度为151.0℃,反应时间为3.5 h,醇油摩尔比为21:1时,生物柴油的收率达99.02%。此外,该催化剂表现出优良的重复利用性。
[Abstract]:Biodiesel is a kind of environmental friendly and renewable biomass energy, can be used as a substitute for petroleum energy fuels, with good market prospects. And the key to produce biodiesel is a highly efficient heterogeneous catalyst preparation. Currently used in catalytic synthesis of biodiesel heterogeneous catalyst supported more species, which the ionic liquid due to environmental protection has been widely concerned. The purpose of this study is to design and prepare a series of acidic mesoporous materials, and acidic ionic liquid immobilized, get double acid properties of supported ionic liquid catalyst; transesterification of soybean oil and methanol to biodiesel synthesis reaction as a probe, double acid characteristics on the preparation of supported ionic liquid catalysis. Firstly, using one step hydrolysis co condensation and combination of hydrothermal technique, a series of acid hybrid mesoporous materials were synthesized by using SO_4~ (2-) -x/ ZrO_2-SiO_2-y. by Fourier transform infrared spectroscopy, NMR (29Si MAS NMR) and X ray photoelectron spectroscopy were used to characterize the composition and structure of hybrid materials, the three together to verify the synthesis of hybrid materials; through the analysis of wide angle X ray diffraction and N2 physical adsorption were determined to characterize the pore structure properties of the hybrid materials, find the synthesis hybrid materials have excellent mesoporous structure; using acid-base titration of the hybrid material surface acidity were measured. The results show that the hybrid materials on the surface of Br? Nsted Acid capacity is mainly composed of the active component SO_4~ (2-) the amount of decision. Secondly, the surface grafting method of acidic ionic liquids - SO3 h-functionalized hydrogen sulfate ([Ps-im]HSO4) immobilized to hybrid mesoporous materials SO_4~ (2-) -x/ZrO_2-SiO_2-y, a series of supported ionic liquid to prepare SO_4~ (2-) -x/ ZrO_2-SiO_2-y-IL. catalyst of the series. The structure characteristics of excellent and unique double acid properties, its catalytic activity than the homogeneous catalyst is high, more than a single acid supported ionic liquid SBA-15-IL. by Fourier transform infrared spectroscopy, X ray diffraction, N2 physical adsorption, TEM and TGA characterization means, the structure of the catalysts, composition were analyzed. In addition, the SO_4~ (2-) -1.2/ZrO_2-SiO_2-1.0-IL as an example, the single factor optimization of process parameters on the transesterification were obtained, the appropriate process is: reaction temperature 140 C, reaction time 4 h, methanol to oil molar ratio 30:1, catalyst 5 wt% dosage (percentage based on the quality of soybean oil), under these conditions, the biodiesel yield was over 96%; but in the process of repeated use, the catalyst activity gradually decreased, the reason may be caused by a hydrophilic carrier adsorption of glycerol. Finally, in order to enhance the clutter The hydrophobic material, so as to improve the reusability of the immobilized ionic liquids, the synthesis process of the hybrid materials, by using silicone ((CH3CH2O) 3Si-Et-Si (OCH2CH3) 3, BTEE) to replace the inorganic silicon (four ethyl orthosilicate, TEOS), that of inorganic hybrid materials for organic modification the synthesis of organic inorganic hybrid materials of SO_4~ (2-) /ZrO_2-SiO_2 (Et), and different amount of ionic liquid supported by Fourier transform infrared spectroscopy, 1H NMR, X ray photoelectron spectroscopy, X ray diffraction, transmission electron microscopy, N2 adsorption test and thermogravimetric characterization methods of organic-inorganic hybrid materials and supported ionic liquid composition, pore structure, thermal stability and acid site types are analyzed; in addition, the contact angle measurement instrument of hydrophobic carrier modification effect were investigated. The ionic liquid immobilized for transesterification reaction The catalyst, using single factor and response surface analysis on the reaction parameters were optimized. The results showed that: in the ionic liquid loading is 2.50 mmol - g~ (-1), the amount of catalyst (percentage based on the quality of soybean oil) was 5 wt%, the reaction temperature is 151 DEG C, the reaction time is 3.5 h, the molar ratio of methanol to oil for 21:1, the biodiesel yield was 99.02%. in addition, the catalyst exhibited excellent reusability.

【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TE667

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