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对钯碳催化剂(Pd/AC)上对苯二甲酸(TA)加氢精制过程进行了研究,结合反应体系的热力学分析,对该体系中的反应历程、反应特性进行了探讨,并对工业过程进行取样分析验证实验结果。结果表明:加氢精制工艺过程主要发生了两类反应,即加氢反应和脱羰反应,但脱羰反应的并存并未从本质上影响最终精制目的,即降低TA中对羧基苯甲醛(4-CBA)的含量。加氢反应是一个串联反应,即先由4-CBA加氢生成对羟甲基苯甲酸(4-HM BA),反应速率非常快,而后4-HM BA进一步加氢生成对甲基苯甲酸(4-PT),相对速率较慢;脱羰反应的进行程度与反应体系中存在的微量氧密切相关,溶解的微量氧对脱羰反应有促进作用,而氢气则会抑制脱羰反应。
The hydrotreating of terephthalic acid (TA) on palladium-carbon catalyst (Pd / AC) was studied. The reaction process and reaction characteristics of the system were discussed in combination with the thermodynamic analysis of the reaction system. The industrial processes Sample analysis to verify the experimental results. The results show that there are two main reactions in the hydrotreating process, that is, hydrogenation reaction and decarbonylation reaction, but the coexistence of decarbonylation reaction does not essentially affect the final purification purpose, that is, to reduce the yield of carboxybenzaldehyde (4 -CBA) content. The hydrogenation reaction is a series reaction, that is, the 4-HMBA is hydrogenated from 4-CBA and the reaction rate is very high. Then, 4-HMBA is further hydrogenated to form p-methylbenzoic acid 4-PT). The decarbonylation reaction was closely related to the trace oxygen present in the reaction system. The dissolved trace oxygen promoted the decarbonylation reaction while hydrogen inhibited the decarbonylation reaction.