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    醋酸异丙酯催化加氢制双醇反应网络及动力学研究

    Reaction Networks and Dynamics of Isopropyl Acetate Hydrogenation to Produce Dual Alcohols

    • 摘要: 以羧酸酯为原料催化加氢同时制备两种不同(或相同)的醇是一条绿色清洁的原子经济工艺路线。研究采用自主开发的20Cu-8ZnO/SiO2-5K2O催化剂用于醋酸异丙酯加氢制备乙醇和异丙醇的反应体系。通过对催化剂各组分作用分析及主副反应剖析,结合反应产物组成及分布,提出了反应机理和反应网络。采用三段控温的固定床反应器,消除内、外扩散影响后在反应压力5 MPa、氢气与醋酸异丙酯进料摩尔比为30~60、醋酸异丙酯进料流量0~0.20 mL·min-1及反应温度250~280℃的条件下,实测了醋酸异丙酯加氢反应的本征动力学数据;在合理简化反应网络的基础上,建立了本征动力学模型,拟合了模型参数,并进行了模型参数物理意义分析和模型适定性检验。结果表明:当氢酯进料摩尔比≥30,催化剂粒径≤0.30 mm,内、外扩散阻力均已消除;以Matlab软件中非线性最小二乘法拟合结果与动力学实验测定数据吻合良好;在实验范围内,建立的本征动力学模型对醋酸异丙酯加氢制备乙醇和异丙醇反应高度适定。

       

      Abstract: Hydrogenation of carboxylic acid esters to prepare alcohols is a green and atom-economy process. Ethanol and isopropanol production via isopropyl acetate hydrogenation catalyzed with 20Cu-8ZnO/SiO2-5K2O was studied. The reaction mechanism and network were proposed by analyzing the roles of catalyst components, as well as the composition and distribution of reaction products. After eliminating internal and external diffusion resistance, intrinsic kinetic data in a fixed bed reactor with three temperature control sectors were studied under the conditions of: feeding hydrogen ester molar ratio 30~60, isopropyl acetate feed flow 0~0.20 mL·min-1 and reaction temperature 250~280℃ at 5.0 MPa. Intrinsic dynamic models were established and the model parameters were fitted after simplification of the reaction network. Moreover, the applicability of the model was discussed by studying the physical meaning of the model parameters. Results show that the internal and external diffusion resistance is eliminated when the flow rate of isopropyl acetate is over 0.04 mL·min-1 and the catalyst particle size is below 0.30 mm. The results obtained by nonlinear least-square methods using Matlab are in good agreement with the dynamic experimental data, which means the established intrinsic kinetic models are suitable for the experimental conditions studied.

       

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