(442b) 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: sjzhang@home.ipe.ac.cn

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

Acknowledgments

This work was supported byNational Basic Research Program of China
(2009CB219901), and National Science
Fund of China (21006117 and 20936005).