Abstract Oxidation of crotonaldehyde to crotonic acid is an important chemical reaction process because crotonic acid, its derivative and copolymer are ubiquitous in the productions of chemical, cosmetic, and medicines. However, the reactor safety and process efficiency are still not satisfactory. In order to solve such problems, a novel reactor of gas-liquid-solid mini-fluidized bed with bed inner diameter of 3 mm was developed to carry out the selective catalytic oxidation reaction. The effects of operation conditions and solid particle properties on the conversion rate of reactant crotonaldehyde and the selectivity of product crotonic acid were investigated. The causes of these effects are explained from the standpoint of residence time and gas-liquid mass transfer flux. Moreover, the comparison of reactor performance between the three-phase mini-fluidized bed and the batch stirred tank reactor as a traditional one was made to evaluate the performance of such a reactor. Experimental results show that the average reaction or conversion rate of the mini-fluidized bed is about 30 times much higher than that of batch stirred tank reactor to evaluate the improved performance. But the selectivity is less affected by the operation conditions and solid particle bed properties. The size reduction of three-phase mini-fluidized bed decreases the mass transfer distance of molecular diffusion, and the solid particles and mini-bubbles not only provide the higher specific interface area but also cause hydrodynamics changes that is to intensify the interface disturbance, which effectively accelerate the mass transfer.

中文翻译：

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气-液-固微流化床催化氧化巴豆醛制备巴豆酸

摘要 巴豆醛氧化为巴豆酸是一个重要的化学反应过程，因为巴豆酸及其衍生物和共聚物广泛存在于化工、化妆品和医药生产中。然而，反应器的安全性和工艺效率仍然不能令人满意。为解决上述问题，研制了一种新型床内径为3 mm的气-液-固微型流化床反应器，用于进行选择性催化氧化反应。考察了操作条件和固体颗粒性质对反应物巴豆醛转化率和产物巴豆酸选择性的影响。从停留时间和气液传质通量的角度解释了这些影响的原因。而且，将三相微型流化床与传统的间歇式搅拌釜反应器的反应器性能进行比较，以评价这种反应器的性能。实验结果表明，微型流化床的平均反应或转化率比间歇搅拌釜反应器高约30倍，以评估改进的性能。但选择性受操作条件和固体颗粒床性质的影响较小。三相微流化床的尺寸减小降低了分子扩散的传质距离，固体颗粒和微气泡不仅提供了更高的比界面面积，而且引起了流体动力学变化，即加剧了界面扰动。有效地加速传质。