Novick, Kim & Lee, PLLC
Method for separation of close-boiling mixture of polyols
This invention discloses an approach for the separation of the close-boiling mixture of polyols. The raw material is ethylene glycol containing miscellaneous polyols (such as 1,2-propylene glycol and 1,2-butanediol). Over an acid catalyst, these miscellaneous polyols, through (1) a dehydration reaction, (2) pinacol rearrangement, and (3) acetalization or ketalization reaction, are converted into aldehydes (small amounts), acetals, and ketals (trace amount), which are simultaneously and readily separated via distillation. Meanwhile, after the reaction, the mixture is further separated to obtain an ethylene glycol product at a high purity. The invention provides a technique to remove the miscellaneous polyols from ethylene glycol via liquid-phase dehydration reactions under mild conditions, with low energy consumption. In particular, this approach is markedly effective for the removal of 1,2-butanediol that is difficult to be removed via conventional techniques. The purity of the resulting ethylene glycol product is high, and value-added acetals or ketals are co-produced.
DALIAN INSTITUTE OF CHEMICAL PHYSICS, CHINESE ACADEMY OF SCIENCES
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B01D Y02P B01D B01J C07C C07C Y02P B01D C07C C07C B01D B01D B01D B01J Y02P B01J
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Xiaodong Shuo Tao Mingyuan Weizhen Aiqin
Wang Al Zhang Zheng Li Wang