关键词: 热力学, 动力学, 加氢, 反应工程, 基团贡献法

Abstract:

1,6-Hexanediol is an important building-block chemical and applied widely in the synthesis of specialty chemicals and a variety of polymers, primarily in polyesters, polyurethanes and polyamides. Industrially, a most common route for 1,6-hexanediol production is catalytic hydrogenation of dimethyl adipate. Thermodynamic analysis and kinetic study are important links in the study of chemical process, but few reports have been reported on the dimethyl adipate hydrogenation. Hence, thermodynamic data of dimethyl adipate (DMA) and 1,6-hexanediol were calculated by group contribution method in this work, and the enthalpy, entropy, Gibbs free energy and equilibrium constant of reaction under different reaction conditions were calculated. As can be seen from the calculated results that the decreases of temperature and increases of pressure are beneficial to increasing the reaction equilibrium constant. Besides, kinetic study of DMA hydrogenation was preformed in the fixed bed tubular reactor. Experiments were carried out under the following conditions: temperature 473.15—514.15 K, pressure 2.0—6.1 MPa, LHSV 1.28—2.55 h^-1, molar ratio of H₂ to DMA 150—270. The exponential model was employed to describe the reaction rate and the obtained activation energy for dimethyl adipate hydrogenation was 63.55 kJ·mol^-1. The reaction order of dimethyl adipate and hydrogen are 0.63 and 0.40 respectively. The statistical test results show that the model can better describe the DMA hydrogenation reaction.

Key words: thermodynamics, kinetics, hydrogenation, reaction engineering, group contribution method