对叔丁基杯[4]芳烃乙酸萃取Cr^(3+)的反应研究

Study on the reaction of ρ-tert-butylcalix[4]-arene extraction of Cr^(3+)

报道了以对叔丁基杯[4]芳烃乙酸(简称杯[4]水解)为萃取剂,从硝酸体系中萃取Cr3+的反应机理及反应热力学性质。通过考察溶液pH值对萃取分配比的影响,确认杯[4]水解萃取Cr3+的机理,并得到了萃取反应的表观平衡常数K=1.815×103;通过考察反应温度对分配比的影响,求得萃取热焓ΔH=69.89 kJ/mol;由ΔH和表观平衡常数K计算了自由能ΔG=-18.601 kJ/mol和熵变ΔS=294.97 J/(mol-1.K-1)。杯[4]水解萃取Cr3+的反应是一个吸热反应。

The mechanism and thermodynamic property of the ρ-tert-butylealix[ 4 ]-arene acetate （hydrolisis of cup [ 4 ] ） extraction of Cr^3＋ from nitric acid system were reported. By investigating the influence of the change of pH on allocating proportion, the mechanism of extracting Cr^3＋ with the hydrolisis of cup [ 4 ] was confirmed, and the apparent equilibrium constant K = 1. 815 ×10^3 was obtained; by investigating the influence of the temperature change on allocating proportion, the heat content AH = 69.89 kJ/mol can be obtained, the free energy AG = - 18. 601 k J/tool and the entropy AS = 294.97 J/（ tool^-1·K^-1 from ΔH and K. The reaction of Cr^3＋ extraction is endothermie.