Integration technology of the efficient and energy-saving synthesis of ethylene glycol and carbonate
Background and significance
Ethylene glycol（EG）is chemical of industrial importance, which has been widely used in electronic, medical, construction, automotive and other industrial areas. EG demand in China has been greatly reached to about 9.5 million t/a now, but the current capacity is serious shortage with only 3.23 million t/a. In addition, the current manufacture method for EG is the direct hydration of ethylene oxide (EO) with the disadvantages of high energy-consumption, high water demand (EO:H2O =1:22, molar ratio) and low EG yield (EG selectivity<90%). Therefore, developent of efficient and energy-saving synthesis of EG is highly required.
Progress and characteristic
Herein, an integration technology of the efficient and energy-saving synthesis of ethylene glycol and carbonate was developed with low water demand (EO:H2O=1:1.5, molar ratio), energy-saving (~30%), and high EG selectivity (>99%), in addition, CO2 released from the upstream of ethylene oxidation could be flexiblly utilized for the preparation of high value-added chemicals, such as cyclic carboante and dimethyl carbonate according to the market needs. Up till now, 1000 hrs industrial sidestream test for the whole process was carrided out, in which, the technical problems such as ionic liquid catalysts development, catalyst immobilization, and carrier swelling were resolved. The corresponding reactors for the cycloaddtion, alcoholysis and hydrolysis reactions were also developed and optimized. Futhermore, integration optimization of the whole process was completed, by which a 80 kt/a process package was formed. Recently, a technology appraisal of the new techonogy was passed on Feb. 20, 2011 organized by the Chinese Academy of Science, and the appraisal group highly evaluated that "the new technology reached an international advanced level, and the establishment of an industrial demonstration unit as soon as possible shoult be promoted."