双酸位固体催化剂的制备及其在生物柴油合成中的应用

发布时间：2018-05-18 00:24

本文选题：生物柴油 + 固体酸催化剂　；参考：《贵州大学》2017年硕士论文

【摘要】：石化能源的不断消耗和环境问题的日益加重,促进了可再生清洁能源的研究与发展。生物柴油具有可生物降解、无硫、可再生、高润滑性等优点,是重要的可替代能源之一。为降低成本,通常以非食用油(如麻疯树油)为原料来制备生物柴油。此外,在食品加工过程中会产生大量的游离脂肪酸副产物,将其与小分子醇的酯化反应是制备生物柴油的另一重要途径。而双酸位固体催化剂中活性位点可协同作用,有利于提高其在酯化酯交换反应中的催化活性。基于此,本文设计合成了三种固体酸催化剂,并用于催化酯化酯交换反应制备生物柴油。研究结果如下:(1)制备得到三种金属氟化物(MgF_2、ZnF_2、AlF3),并将该催化剂用于油酸与甲醇酯化反应,测试催化剂的催化活性。通过XRD、NH3-TPD、TGA等对催化剂进行表征。通过对比发现ZnF_2在油酸酯化反应中催化活性最高,在一定反应条件下(醇油摩尔比10/1、催化剂用量8 wt%、反应时间6 h、反应温度140°C),油酸转化率为92%。催化剂ZnF_2重复使用四次后,油酸转化率几乎没有降低,表明催化剂具有优良的重复使用性。(2)分别采用浸渍法、溶剂热法制备了一系列TPA-金属氟化物固体催化剂,通过FT-IR、XRD、EDS、NH3-TPD、CO2-TPD、N2-吸附解析等对催化剂进行了表征;并将该类催化剂用于油酸与甲醇的酯化反应,探讨不同催化剂的催化活性,其中Mg20F39TPA-1.0催化活性最好,在同等条件下其催化活性甚至比TPA的催化活性高。这主要是因为L酸位点的引入,有利于酯化反应的发生。而对于催化剂30 wt%TPA/MgF_2和30 wt%TPA/ZnF_2,其酸密度相当,但30 wt%TPA/MgF_2催化活性更好,主要是由于30 wt%TPA/MgF_2比表面积更高,有效活性位点更多。通过单因素法优化酯化反应条件,在最佳反应条件下(醇油摩尔比9/1、催化剂用量5 wt%、反应时间4 h、反应温度80°C),油酸转化率高达95%。催化剂重复使用5次后,催化活性几乎没有降低,且对重复使用后的催化剂进行表征,发现催化剂的结构几乎没有发生变化,表明催化剂具有较好的重复使用性。对Mg20F39TPA-1.0催化油酸酯化反应的反应制定了动力学模型,且活化能相对TPA为催化剂时低,为43.9 kJ/mol,进一步证明了双酸位的重要性。采用曲面响应法探讨各反应条件对酯化反应的影响。Mg20F39TPA-1.0催化麻疯树油(19.35 mg KOH/g)与甲醇酯化酯交换反应,在醇油摩尔比30/1、催化剂用量8 wt%、反应时间12 h、反应温度140°C的反应条件下,生物柴油产率高达93%。(3)引入模板剂P123,制备多孔金属氟化物,并通过FT-IR、XRD、EDS、NH3-TPD、N2-吸附解析等对催化剂进行了表征。将TmZnF_2用于油酸酯化反应中,其中,T6ZnF_2催化活性最佳。在醇油摩尔比9/1、催化剂用量5 wt%、反应时间6 h、反应温度120°C的反应条件下,油酸转化率为96%。将T6ZnF_2用于高酸值麻疯树油(15.47 mg KOH/g)与甲醇同时酯化酯交换反应中,并采用单因素法优化反应条件,在醇油摩尔比30/1、催化剂用量10 wt%、反应时间10 h、反应温度100°C的反应条件下,生物柴油产率为95%。催化剂重复使用4次后,油酸转化率几乎没有降低,表明催化剂具有良好的重复使用性。对T6ZnF_2催化高酸值麻疯树油同时酯化酯交换反应体系制定了动力学模型,测得其活化能相对较低,为50.05 kJ/mol。
[Abstract]:The continuous consumption of petrochemical energy and the increasing environmental problems have promoted the research and development of renewable and clean energy. Biodiesel has the advantages of biodegradation, sulfur free, renewable, high skid and so on. It is one of the important alternative energy sources. In order to reduce the cost, the biodiesel is usually prepared with non edible oil (like mad tree oil) as raw material. In addition, there will be a large number of free fatty acid byproducts in the process of food processing, and the esterification reaction with small molecular alcohols is another important way to prepare biodiesel. The active site of the double acid solid catalyst can synergy and improve its catalytic activity in the esterification reaction. Based on this, this paper is designed and combined. Three kinds of solid acid catalysts were prepared and used to catalyze the preparation of biodiesel by esterification reaction. The results were as follows: (1) three kinds of metal fluoride (MgF_2, ZnF_2, AlF3) were prepared, and the catalyst was used to esterification of oleic acid to methanol and the catalytic activity of the catalyst was tested. The catalyst was characterized by XRD, NH3-TPD, TGA and so on. It is found that ZnF_2 has the highest catalytic activity in oleic acid esterification. Under certain reaction conditions (alcohol oil mole ratio 10/1, catalyst dosage 8 wt%, reaction time 6 h, reaction temperature 140 degree C), the conversion rate of oleic acid is 92%. catalyst ZnF_2 repeated use four times, the conversion rate of oleic acid is not reduced, indicating that the catalyst has excellent reusability (2) a series of TPA- metal fluoride solid catalysts were prepared by impregnation and solvothermal method. The catalysts were characterized by FT-IR, XRD, EDS, NH3-TPD, CO2-TPD, N2- adsorption and so on. The catalyst was used in the esterification of oleic acid and methanol, and the catalytic activity of different catalysts was discussed, in which Mg20F39TPA-1.0 catalyzed the activity. In the same condition, the catalytic activity of the catalyst is even higher than that of TPA. This is mainly due to the introduction of the L acid site, which is beneficial to the esterification reaction. For the catalyst 30 wt%TPA/MgF_2 and 30 wt%TPA/ZnF_2, the acid density is equal, but the 30 wt%TPA/MgF_2 catalytic activity is better, mainly due to the higher ratio of 30 wt%TPA/MgF_2 to the surface area. There are more effective active sites. The esterification conditions are optimized by single factor method. Under the optimum reaction conditions (alcohol oil mole ratio 9/1, catalyst dosage 5 wt%, reaction time 4 h, reaction temperature 80 degree C), oleic acid conversion rate is high to 95%. catalyst for 5 times, the catalytic activity is almost not reduced, and the reused catalyst is characterized. It was found that the structure of the catalyst had almost no change, indicating that the catalyst had good reusability. The kinetic model was established for the reaction of Mg20F39TPA-1.0 to catalyze the esterification of oleic acid, and the activation energy was lower than that of TPA as the catalyst. It was 43.9 kJ/mol, which further proved the importance of diacid sites. The effect of the conditions on the esterification reaction.Mg20F39TPA-1.0 catalyzes the exchange reaction of Jatropha curcas oil (19.35 mg KOH/g) with methanol esterified ester, in alcohol oil mole ratio 30/1, catalyst dosage 8 wt%, reaction time 12 h and reaction temperature 140 degree C, the yield of biodiesel is as high as 93%. (3) and porous metal fluoride is prepared and porous metal fluoride is prepared. The catalyst was characterized by FT-IR, XRD, EDS, NH3-TPD, N2- adsorption and so on. TmZnF_2 was used in the esterification of oleic acid, in which the catalytic activity of T6ZnF_2 was the best. In the alcohol oil molar ratio 9/1, the amount of catalyst was 5 wt%, the reaction time was 6 h, and the reaction temperature was 120 degree C. The oleic acid conversion rate was used for the high acid value of Jatropha curcas oil (15.4). 7 mg KOH/g) and methanol at the same time esterification and transesterification reaction, and using single factor method to optimize the reaction conditions, in alcohol oil mole ratio 30/1, catalyst dosage 10 wt%, reaction time 10 h, reaction temperature 100 degree C reaction conditions, biodiesel yield of 95%. catalyst reused 4 times, the conversion rate of oleic acid almost did not decrease, indicating the catalyst has Good reusability. A kinetic model was established for the simultaneous esterification reaction system of the high acid value leprosy tree oil catalyzed by T6ZnF_2, and the activation energy was relatively low, which was 50.05 kJ/mol..
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TE667

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