Phase Diagrams of Aqueous Two-Phase Systems with Organic Salts and F68 Triblock Copolymer at Different Temperatures

详细信息    查看全文

• 作者：Guilherme Dias Rodrigues ; Leonel da Silva Teixeira ; Gabriel Max Dias Ferreira ; Maria do Carmo Hespanhol da Silva ; Luis Henrique Mendes da Silva ; Raquel Moreira Maduro de Carvalho
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2010
• 出版时间：March 11, 2010
• 年：2010
• 卷：55
• 期：3
• 页码：1158-1165
• 全文大小：205K
• 年卷期：v.55,no.3(March 11, 2010)
• ISSN：1520-5134

文摘

Phase diagrams of aqueous two-phase systems (ATPS) composed of F68 triblock copolymer + salt + water were constructed at different temperatures. The ATPS composed of F68 + (NH₄)₃C₆H₅O₇ + H₂O was investigated at (278.15, 288.15, and 298.15) K, and the F68 + Na₃C₆H₅O₇ + H₂O, F68 + Na₂C₄H₄O₆ + H₂O, F68 + Na₂CO₃ + H₂O, and F68 + Na₂C₄H₄O₄ + H₂O systems were examined at (283.15, 298.15, and 313.15) K. For all ATPS, the position of the binodal curve was affected by temperature, evidence of the enthalpic contribution to the formation of the biphasic system. As temperature increased, both the extent of the two-phase region in the diagrams and the slope of the tie line increased. The salt Na₃C₆H₅O₇ was more effective in promoting phase separation than (NH₄)₃C₆H₅O₇. The capacity of the different anions tested for inducing ATPS formation with F68 followed the order: CO₃²⁻ > C₆H₅O₇³⁻ > C₄H₄O₆²⁻ > C₄H₄O₄²⁻. The consistencies of the tie-line experimental compositions were improved by applying the Othmer−Tobias correlation. The experimental equilibrium data of ternary systems were correlated to find new interaction energy parameters through the NRTL model for the activity coefficient. The results were considered excellent with global root-mean-square deviations as low as 0.93 %.