The phase behavior of n-ethylpyridinium tetrafluoroborate and sodium-based salts ATPS and its application in 2-chlorophenol extraction

In this paper, the aqueous two-phase systems (ATPS) containing n-ethylpyridinium tetrafluoroborate ([EPy]BF4), sodium-based salts, and water were studied and the extraction efficiency of 2-chlorophenol was measured to study the ATPS performance in extracting phenolic compounds. The binodal curves of (EPy]BF4 + sodium carbonate (Na2CO3) ATPS and [EPy]BF4 + sodium dihydrogen phosphate (NaH2PO4) ATPS have been determined at 308.15 K, 318.15 K, and 328.15 K and atmospheric pressure. After getting good correlation with Merchuk equation, the binodal curves together with gravimetric method were used to calculate the tie-lines data. Furthermore, the reliability of tie-lines data was verified using Othmer-Tobias and Bancroft equations. Then, the salt influence and temperature influence on the phase behavior were discussed and the results show the salt-outing ability of Na2CO3 is better than NaH2PO4. With the aim of studying the ATPS performance in extracting phenolic compounds, extraction efficiency for 2-chlorophenol at different temperatures were studied and the results show that [EPy]BF4 + Na2CO3 ATPS is preferred than [EPy]BF4 + NaH2PO4 ATPS in applications. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

This study investigated the aqueous two-phase systems (ATPS) containing [EPy]BF4, sodium-based salts, and water to extract 2-chlorophenol, demonstrating that the salt-outing ability of Na2CO3 is better than NaH2PO4. The results showed that [EPy]BF4 + Na2CO3 ATPS outperformed [EPy]BF4 + NaH2PO4 ATPS in applications for extracting phenolic compounds.