蓖麻油脱水反应催化剂的制备及性能研究

发布时间：2018-03-25 14:37

  本文选题：蓖麻油　切入点：脱水　出处：《安徽理工大学》2017年硕士论文

【摘要】：蓖麻油可用于合成许多工业制品,这些工业制品在诸多领域有着广泛的应用。因此,加大对蓖麻油深加工的发展力度是必然的趋势。目前,蓖麻油脱水这一条工业链已日渐成熟,但是还存在许多问题。由于蓖麻油需要在较高的温度下进行脱水反应,在反应过程中,易发生热聚合、热裂解等副反应,使得蓖麻油脱水程度不高。为了提高蓖麻油脱水反应效率,本文将NaHSO4负载于MCM-41中制得NaHSO4/MCM-41催化剂,并通过改变催化剂制备方法和对催化剂的物理性能进行改性,提高催化剂的催化效率。将NaHSO4负载于MCM-41上制得NaHSO4/MCM-41催化剂。通过对催化剂进行XRD、N2吸附脱附、NH3-TPD、FT-IR、TG、吡啶红外分析研究催化剂的物理化学性质。分析结果表明:MCM-41的六方介孔结构没有改变,而且NaHS04成功的负载到MCM-41上。实验结果表明:NaHSO4/MCM-41的催化效果比NaHSO4的催化效果好。在最优工艺条件下:反应时间70 min、NaHSO4负载量25 wt%、反应温度240℃、催化剂用量4 wt%,催化产物的碘值和羟值分别为134.2 g(I2)/100g 和 17.3 mg(KOH)/g。以不同浸渍顺序合成了十二烷基三乙氧基硅烷(DTEOS)改性的NaHSO4/MCM-41催化剂(硅烷化催化剂)并将其应用于蓖麻油脱水反应中。通过 XRD、N2 吸附脱附、SEM、TEM、红外、XPS、29Si MAS NMR、接触角、NH3-TPD和吡啶红外等表征分析催化剂的物理化学性能。分析结果表明:硅烷化提高催化剂的疏水性;硅烷化催化剂的不同的浸渍步骤对催化剂的NaHSO4的分散度、比表面积、酸位分布和疏水性能均有很大的影响。评价结果表明:硅烷化催化剂的催化活性均高于NaHSO4/MCM-41的催化活性;在硅烷化催化剂中,同时浸渍DTEOS和NaHSO4的催化剂作用后得到的产物具有最高的碘值和最低的羟值。以超临界浸渍法制备了 NaHSO4/MCM-41-SUP催化剂作为蓖麻油脱水的催化剂,并以常规浸渍法制备的NaHSO4/MCM-41-IMG催化剂作为对照。结果证实:NaHSO4/MCM-41-SUP的催化效果和重复使用性能比NaHSO4/MCM-41-IMG好。采用XRD、N2吸附脱附、NH3-TPD、吡啶红外、红外、TG和CHNS元素分析来测试催化剂的物理化学性能。根据表征结果,超临界二氧化碳浸渍方法有利于提高NaHSO4的分散度、增加NaHSO4和MCM-41间的作用位点、增强催化剂的热稳定性并且提高催化剂的中酸位和Bransted酸位的量。因此,NaHSO4/MCM-41-SUP中NaHSO4的浸出量和积碳量会降低,从而它的失活速率会降低。此外该催化剂的重复使用性能很好。经过六次使用后,NaHSO4/MCM-41-IMG作用后得到的产物的碘值从135.2 g(I2)/100g降为114.2 g(I2)/100g,羟值从 14.7 mg(KOH)/g 增为 59.1 mg(KOH)/g(NaHSO4/MCM-41-IMG中积碳量和S元素浸出量分别为11.5 wt%和51.8%),而NaHSO4/MCM-41-SUP作用后得到的产物的碘值从137.5 g(I2)/100g降为134.5 g(I2)/100g,羟值从13.1 mg(KOH)/g 增为 16.5 mg(KOH)/g(NaHSO4/MCM-41-SUP 中积碳量和 S 元素浸出量分别为4.7 wt%和10.9%)。
[Abstract]:Castor oil can be used to synthesize many industrial products, which are widely used in many fields. Therefore, it is an inevitable trend to increase the development of castor oil deep processing. The industrial chain of castor oil dehydration has matured gradually, but there are still many problems. Since castor oil needs dehydration reaction at a higher temperature, it is easy to take place in the process of thermal polymerization, pyrolysis and other side reactions. The degree of dehydration of castor oil is not high. In order to improve the efficiency of dehydration reaction of castor oil, the NaHSO4/MCM-41 catalyst was prepared by loading NaHSO4 in MCM-41, and the physical properties of the catalyst were modified by changing the preparation method of the catalyst. The catalytic efficiency of the catalyst was improved. The NaHSO4/MCM-41 catalyst was prepared by loading NaHSO4 on MCM-41. The physical and chemical properties of the catalyst were studied by the adsorption and desorption of NH _ 3-TPD-FT-IRT _ (TG) on the catalyst. The results showed that the hexagonal mesoporous structure of the catalyst was not changed, the results showed that the hexagonal mesoporous structure of the catalyst was not changed. Moreover, NaHS04 was successfully loaded on MCM-41. The experimental results showed that the catalytic effect of w / NaHSO _ 4 / MCM-41 was better than that of NaHSO4. Under the optimum conditions, the reaction time was 70 min, the loading amount of NaHSO _ 4 was 25 wt, and the reaction temperature was 240 鈩，

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