Kinetic separation of heavy metal ions with new alkylated 8-quinolinols and its application to the environmental analysis

研究了新合成的烷基化8-喹啉醇类化合物如5-辛氧甲基-8-喹啉酚(HO_8Q)、2-甲基-5-辛氧甲基-8-喹啉酚(HMO_8Q)和5-(4-nitrophenylazo)-7-(4-ethyl-1-methyloctyl)-8-quinolinol(HNEQ)，对Ga(Ⅲ)、Mo(VI)、Zn(II)的萃取性能，建立了高选择性的分离体系。用HO_8Q从弱酸性溶液Ga(O_8Q)_3(Kex=10^&lt；3.2&gt；)中萃取Ga(III)。另一方面，在HMO_8Q的情况下，萃合物为Ga(OH)(MO_8Q)_2(Kex=10^&lt；-4.2&gt；)。用HO_8Q和HMO_8Q从含氯离子的弱酸性溶液中萃取Ga(III)，分别为Ga(O_8Q)_3和Ga(Cl)(MO_8Q)_2。HO_8Q在正庚烷中萃取Ga(III)的速率控制步骤应是水相中Ga~(3+)和Ga(OH)~(2+)与HO_8Q和H_2O_8Q的竞争反应。与庚烷相比，三氯甲烷的萃取速度很慢。用HO_8Q和HMO_8Q从强酸性溶液中萃取Mo(VI)，并与Co(II)、Fe(III)、Cu(II)等金属离子分离。测定了MoO_2(O_8Q)_2和MoO_2(MO_8Q)_2的萃取常数分别为10^&lt；17.7和14.9&gt；用HMO_8Q从盐酸中萃取Pd(II)，生成Pd(MO_8Q)_2(Kex=10^&lt；13.3&gt；)。萃合物在氯仿中用0.3M SCN^-溶液在pH 3.0下反萃取，萃取率随溶剂种类的不同而不同。因此，可以利用萃取率的差异和反萃取过程来选择性地将Pd(II)与其他金属离子分离。研究了HNEQ对锌(II)的协同萃取作用。用HNEQ分离了锌(II)和镉(II)，这些结果有望应用于重金属离子的分离。

The solvent extraction of Ga(III), Mo(VI), Zn(II) with alkylated 8- quinolinols such as 5-octyloxymethyl-8-quinolinol(HO_8Q), 2-methyl-5- octyloxymethyl-8-quinolinol(HMO_8Q) and 5-(4-nitrophenylazo)-7-(4-ethyl-1-methyloctyl)-8-quinolinol(HNEQ), which were newly prepared, was investigated to develop highly selective separation systems.1. Ga(III) was extracted with HO_8Q in heptane from weakly acidic solution as Ga(O_8Q)_3 (Kex = 10^<3.2>). On the other hand, in a case of HMO_8Q, the extracted complex was to be Ga(OH)(MO_8Q)_2 (Kex = 10^<-4.2>). Ga(III) was extracted with HO_8Q and HMO_8Q in heptane from weakly acidic solution containing chloride ion as Ga(O_8Q)_3 and Ga(Cl)(MO_8Q)_2, respectively.2. The rate determining steps of the extraction of Ga(III) with HO_8Q in heptane should be the competitive reactions of Ga^<3+> and Ga(OH)^<2+> with HO_8Q and/or H_2O_8Q in an aqueous phase. The extraction in chloroform is very slow comared with that in heptane.3. Mo(VI) was extracted with HO_8Q and HMO_8Q in chloroform from very strong acidic solution and separated from other metal ions such as Co(II),Fe(III) and Cu(II). The extraction constants were determined to be 10^<17.7> for MoO_2(O_8Q)_2 and 10^<14.9> for MoO_2(MO_8Q)_2 respectively.4. Pd(II) was extracted with HMO_8Q in chloroform from hydrochloric acid as Pd(MO_8Q)_2 (Kex = 10^<13.3>). The extracted complex in chloroform was back extracted with 0.3 M SCN^- solution at pH 3.0.The extraction rate is remarkably dependent on the kinds of solvents. Consequently, Pd(II) can be selectively separated from other metal ions by using the difference in the extraction rate and by the procedure of the back extraction.5. The synergistic extraction of Zn(II) with HNEQ was extracted. Zn(II) was found to be separated from Cd(II) with HNEQ.These results will be expected to apply to the separation of heavy metal ions.