Polyethylenimine-Assisted Extraction of 伪-Tocopherol from Tocopherol Homologues and CO2-Triggered Fast Recovery of the Extractant

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• 作者：Guoqiang Yu ; Yangyang Lu ; Xianxian Liu ; Wen-Jun Wang ; Qiwei Yang ; Huabin Xing ; Qilong Ren ; Bo-Geng Li ; Shiping Zhu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：October 15, 2014
• 年：2014
• 卷：53
• 期：41
• 页码：16025-16032
• 全文大小：323K
• ISSN：1520-5045

文摘

The separation of natural homologues provides a great challenge due to high similarities of their structures and properties. In this work, the use of the polymeric extractant polyethylenimine (PEI) for the separation of 伪-tocopherol from the tocopherol homologues was investigated. Various PEI鈥揷osolvent solutions were used to extract tocopherols from their hexane solutions. The effects of PEI molecular weight, cosolvent type, and PEI鈥揷osolvent composition were systematically studied. High distribution and selectivity coefficients of tocopherols were obtained with PEI鈥揳crylonitrile (ACN) as the extractant. A clear advantage of PEI extractant is its stimuli-responsive property triggered by CO₂. PEI鈥揺xtracted tocopherols could be replaced and released from PEI chains with CO₂ bubbling, with PEI鈥揅O₂ precipitated out from the extract phase, which greatly facilitates the back extraction of tocopherols and the recovery of PEI for reuse. With CO₂ bubbling, it took only three back extractions to recover over 90% tocopherols, compared with 12 in theory without CO₂ treatment. Precipitated PEI鈥揅O₂ could be redissolved in cosolvent for reuse by N₂ bubbling and heating. The distribution coefficients decreased by approximately 10% after being recycled three times.