275281 Application of Ionic Liquid for the Efficient and Energy-Saving Synthesis of Ethylene Glycol
Application of Ionic Liquid for the Efficient and Energy-Saving Synthesis of Ethylene Glycol
Jian Sun, Weiguo Cheng, Jinquan Wang, Junping Zhang, Suojiang Zhang*
Institute of Process Engineering, Chinese Academy of Sciences,100190, Beijing, PR China
*Corresponding author: email@example.com
Ethylene glycol (EG) is chemical of importance for synthetic fibers, resins, and antifreeze. The most widely used commercial process to manufacture EG is the direct non-catalytic liquid-phase hydration of ethylene oxide (EO). A large excess of water (20-25 mol water/mol EO) must be used to obtain a high selectivity of EG in the hydration reaction mixture, which consumes a large steam input for products separations. Even so, an achieved typical product mixture is only approximately 90% EG. Therefore, the need to increase EG selectivity but reduce energy cost has spurred the development of alternative routes and the corresponding catalysts.
Recently, the manufacture of EG from EO via ethylene carbonate (EC) intermediate has been regarded as one of the most efficient routes to replace the current method. However, the catalysts still suffer from low activity, harsh reaction conditions and water/air sensitivity. In addition, the requirement of EC separation might be a response to an unsatisfactory compatibility of the two-step reaction catalysts.
Since ionic liquids (ILs) have shown an excellent performance for the synthesis of industrial chemicals substituting for traditional catalysts, herein, we designed and screened binary IL catalysts for the new process, between which one would be active towards the cycloaddition reaction and another could be effective for the hydration process. Effect of various parameters on the new process was studied in detail. It was found that in the presence of water, 1) EO conversion could be enhanced obviously, 2) the molar ratio of components in catalyst had a great effect on the selectivities of EC, EG and diethylene glycol (DEG), and 3) the catalyst was hydrothermally stable and could be reused over 10 times without loss of its activity and selectivity. Based on the results, an economic comparison of the direct hydration process and the new process was investigated by aspen-plus simulation. The total process avoids EC separation, and represents a simple, energy-saving, and cost-effective route to EG with high product quality, as well as easy catalyst recycling.
Keywords: ionic liquid, ethylene glycol, carbon dioxide, synthesis, energy-saving
This work was supported byNational Basic Research Program of China (2009CB219901), and National Science Fund of China (21006117 and 20936005).
See more of this Group/Topical: Topical G: Innovations of Green Process Engineering for Sustainable Energy and Environment