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本文概述了三辛胺(TOA)和三辛基氧化膦(TOPO)的正已烷体系,在低酸条件下协萃硫酸铀酰的条件及机理。重点探讨了三辛胺在水相pH=2.3及(NH_4)_2SO_4浓度为0.5M时形成的萃合物与一般酸度条件下的萃合物不同,并用斜率法,等克分子系列法证明其组成为(R_3NH)_2UO_2(SO_4)_2,协萃后萃合物组成为(R_3NH)_2UO_2(SO-4)_2·TOPO,揭示了在低酸区“TOA+TOPO”体系产生BC类协萃的原因,求得协萃反应平衡常数1gβ_(12)=12.46,得到该反应△H=-16.2k cal·mol~(-1),△G°=-17.0k cal·mol~(-1);△S°=2.68cal·K~(-1)·mol~(-1),并以红外、紫外光谱加以证实。
This article summarizes the conditions and mechanism of the synergistic extraction of uranyl sulfate under the condition of low acid with the n-hexane system of TOA and TOPO. The extraction of trioctylamine by pH = 2.3 and (NH_4) _2SO_4 0.5M is different from that under the general condition of acidity, and its composition (SO_4) _2 and (R_3NH) _2UO_2 (SO-4) _2 · TOPO after co-extraction, revealed the reason for the BC-type co-extraction in “TOA + TOPO” , The reaction equilibrium constant 1gβ 12 = 12.46 was obtained, the reaction △ H = -16.2k cal · mol -1, ΔG ° = -17.0k cal · mol -1; S ° = 2.68cal · K ~ (-1) · mol ~ (-1) and confirmed by IR and UV spectra.