甲醇羰基化制醋酸均相催化体系的研究
重庆大学硕士学位论文
学生姓名：***
指导教师：杜军教授
专业：化学
学科门类：理学
重庆大学化学化工学院
二O一一年四月
Study on Homogeneous Catalyst System for The Production of Acetic Acid by Methanol
Carbonylation
A Thesis Submitted to Chongqing Universityreaction rate
in Partial Fulfillment of the Requirement for the
Degree of Master of Science
By
Li Zhengfei
Supervised by Prof. Du Jun
Major: Chemistry
College of Chemistry & Chemical Engineering of Chongqing
University, Chongqing, China
April 2011
摘要
醋酸是一种重要的化工原料，甲醇羰基化法是目前生产醋酸的主要方法。由于铱基催化剂反应条件温和、活性较高和选择性高而被广泛的研究。在实验室前期研究工作的基础上，对铱基均相催化体系的反应条件进行了进一步的研究，确定了助催化剂在体系中的浓度达到17%时，催化剂的催化活性得
到较好改善。
本文主要的研究内容如下：①在铱基均相催化体系中，甲醇的转化率大于99%，醋酸的选择性可达80%。铱基均相催化体系中，在铱催化剂作用下反应2h 时催化剂活性达到较高水平，甲醇的转化率99.9%，醋酸的选择性80%，醋酸甲酯的选择性为1.7%，羰基化率为79.7%，醋酸的时空收率为7.9 mol/(L.h)。②对铱基催化体系进行重复催化反应，甲醇的转化率保持在90%以上，醋酸的选择性从87%下降到1.5%，羰基化率从90%下降到9.6%，醋酸的时空收率从5.7 mol/(L.h)下降到0.1 mol/(L.h)。③在铱基催化体系中加入促进剂三氯化钌，进行重复催化，连续重复催化5次，甲醇转化率、醋酸选择性以及醋酸的时空收率都表现出较好的稳定性，甲醇的转化率可以达到99%，醋酸的选择性可以达到80%，醋酸的时空收率基本可以保持在5.0~7.8 mol/(L.h)范围内。④在铱基催化体系中加入碘化物后，甲醇羰基化反应的速率得到明显提高，尤其是加入碘化锂后，醋酸的时空收率从5.1 mol/(L.h)增加到16.1 mol/(L.h)。⑤在铱钌催化体系中加入碘化锂后，甲醇羰基化反应的速率、醋酸选择性都得到较大的提高。当催化剂中铱、钌和锂的摩尔比为1:5:1时，可以得到非常高的羰基化反应速率，及醋酸的时空收率为25.6 mol/(L.h)，甲醇的转化率可以达到99.8%，醋酸的选择性可以达到88%，羰基化率88%。⑥采用微波辐射法合成了离子液体（[Bmim]I），并通过核磁检测技术表征，合成的离子液体的纯度高，有利于在催化反应中应用。在铱基催化体系中加入离子液体后，甲醇的转化率明显降低，明显改变了对产物的选择性，更有利于醋酸甲酯的生成。在离子液体参与铱钌催化体系中，进行重复催化，甲醇的转化率在
55%~75%之间，醋酸甲酯的选择性在20~40%之间。⑦对咪唑的金属配合物，进行了甲醇羰基化的初步探索，咪唑配体可以使镍的催化活性得到一定的提高，但是抑制甲醇的转化率提高。
关键词：铱催化剂，钌促进剂，离子液体，均相羰基化体系
ABSTRACT
Acetic acid is an important chemical material, which is produced by methanol carbonylation as the main method. Owing to mild reaction conditions, high activity and high selectivity, iridium-based catalyst has been extensively studied. In the work, the system of iridium-based catalyst based previous research in the laboratory has been investigated comprehensively, and the stability of the catalyst was improved by adding ionic liquid into the homogeneous catalytic system. The reaction conditions of homogeneous catalytic system were discussed further, and the concentration of methyl iodide is 17%, the catalytic activity is improved.
The major research contents are as follows:①The conversion rate of methanol was more than 99%, and the selectivity for acetic acid was 80% in the iridium- iodine catalytic system. The catalyst activity reached a higher level by the catalytic reaction of iridium repeatedly m within 2 h, the conversion rate of methanol was more than 99%, the selectivity for acetic acid was 80%, the selectivity for methyl acet
atec was 1.7%, the carbonylation rate was 79.7% and the space-time yield of acetic acid was 7.9 mol/(L.h) in the homogeneous iridium- iodine catalytic system. ②At the same time, the conversion rate of methanol was above 90%, the selectivity for methyl acetatec was reduced from 87% to 1.5%, the carbonylation rate was decreased range 90% to 9.6%, and the space-time yield of acetic acid was decreased from 5.7 mol/(L.h) to 0.1 mol/(L.h) after catalyzing reaction repeatedly in the iridium- iodine catalytic system. ③The conversion rate of methanol, the selectivity and the space-time yield of acetic acid showed a better stability, then the conversion rate of methanol was up to 99%, the selectivity for acetic acid was 80% and the space-time yield of acetic acid could be maintained from 5.0 mol/(L.h) to7.8 mol/(L.h) by adding promoter of RuCl3into the iridium- iodine catalytic system with the catalysis of 5 times repeatedly. ④The methanol carbonylation reaction rate was promoted, the space-time yield of acetic acid was increased from 5.1 mol/ (L.h) to 16.1mol/ (L.h) by adding iodide into the iridium- iodine catalytic system, especially for lithium iodide, then the methanol carbonylation reaction rate and the selectivity for acetic acid were enhanced . ⑤The experimental results showed that when the molal ratio of iridium, ruthenium and lithium was 1:5:1, a higher rate of methanol carbonylation reaction was achieved and the space-time yield of acetic acid was 25.6 mol/(L.h) ; besides, the conversion rate of methanol was up to
99.8%, the selectivity for acetic acid was 88% and the carbonylation rate was 88%.⑥The ionic liquid of [Bmim] I was synthesized by microwave radiation, and the structure was characterized by the nuclear magnetic resonance (NMR). The results indicated that the purity of ionic liquid was better, which was good for catalytic reactions. The conversion rate of methanol increased with the increase of ionic liquid content, and the process of catalysis was good for preparing methyl acetate. The selectivity for methyl acetate was remained between 55% and 75% in the iridium -ruthenium catalyst system by the catalysis repeatedly, which tend to be promoted. ⑦The methanol carbonylation was carried out for the metal complexes of imidazole, and the results indicated that the catalytic activity of nickel were improved by imidazole ligand to some extent.
Key words: Iridium catalyst, Ruthenium promoter, Ionic liquids, Homogeneous Carbonylation systerm

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