The Synthesis Of A Few Calix"4"arene-Crown Derivatives And Their Extraction Properties And Mechanism

Liquid-liquid solvent extraction is one of the most important unit operations. It has been widely used these years because of the advantages in operations. The development of new extractants has taken an important role in the solvent extraction. Calix[4]arene-crown agent is a kind of the derivative of the third generation supramolecular compound, Calix[4]arene. It has better capabilities of complexing and recognizing for Cs(Ⅰ) than calixarenes or crown ethers because of its special structure.Three new derivatives of Calix[4]arene-crown entitled l,3-di-(1-nonyloxy)-2,4-crown-6-calix[4]arene (NonCalix[4]C6), 1,3-di-(1-decyloxy)-2,4-crown-6-calix[4]arene (DecCalix[4]C6), and 1,3-di-(1-dodecyloxy)-2,4-crown-6-calix[4]arene (DodCalix[4]C6) were synthesized and characterized. The extraction properties and mechanism of heat generation Cs(Ⅰ) and more than 10 coexisting elements with these compounds in HNO3 solution were studied. The results are of great beneficial to effective separation of Cs(Ⅰ) from high level liquid waste (HLW). The co-extraction behavior of Cs(Ⅰ) and Sr(II) was investigated. The main contents were as follows:NonCalix[4]C6, DecCalix[4]C6, and DodCalix[4]C6 were synthesized by the five-step reactions. It was characterized by elemental analysis, FT-IR, TG-DSC, ESI-MS and 1HNMR, respectively. Because pushing electron effect was enhanced by the long-chain alkanes, the persion of substituents were changed. The synthesis route of Calix[4]arene-crown which contains long-chain alkand substituedts have been developed, while the separation and purification methords of Calix[4]arene-crown by column choromatography were also studied.The extraction properities and mechanisms of Cs(Ⅰ) with NonCalix[4]C6,DecCalix[4]C6 and DodCalix[4]C6 were investigated at 298 K. The effects of the HNO3 concentration in the range of 0.4 M to 5.0M, contact time, and temperature on the extraction of Cs(Ⅰ) and the other tested elements were studied. The resules showed that NonCalix[4]C6, DecCalix[4]C6 and DodCalix[4]C6 had excellent extraction for Cs(Ⅰ) over all of the tested elements, which had almost no extraction except Rb(Ⅰ). The extraction of Cs(I) increased obviously with increasing the HNO3 concentration and then decreased. The optimum concentration of HNO3 in the extraction of Cs(I) was 3.0 M HNO3 for DecCalix[4]C6 and DodCalix[4]C6 as well as 4.0 M HNO3 for NonCalix[4]C6. Meanwhile, it was found that the complexiation of Calix[4]arene-crown derivatives with Cs(I) at lower HNO3 concentration and the association of Calix[4]arene-crown derivatives with HNO3 through hydrogen bonding at higher HNO3 concentration were two competitive reaction. The results of contact time experimets showed the fast dynamics of the Cs(Ⅰ) extraction with NonCalix[4]C6, DecCalix[4]C6 and DodCalix[4]C6. The extraction mechanism of Calix[4]arene-crown derivatives for Cs(Ⅰ) were disccued by the slope method. The cpmposition of the extracted complexes between Calix[4]arene-crown and Cs(Ⅰ) was determined to be 1:1 type. The effect of temperature on the distribution ratio was also studied. Some thermodynamic parameters such asΔH°,ΔG°, andΔS°, of the Cs(Ⅰ) and Rb(Ⅰ) extraction were obtained.Both Cs(Ⅰ) and Sr(Ⅱ) are the heat generators conained in HLW. The elimination of them can reduce the long-term radiological risk and prolong the deposit time. The co-separation of Cs(I) and Sr(Ⅱ) using the derivatives of crown ethers and NonCalix[4]C6, DecCalix[4]C6, and DodCalix[4]C6 was studied. The resules showed that it is promising to separate Cs(I) and Sr(Ⅱ) by these mixtured extractants. The diluent effect of the Cs(Ⅰ) extraction was investigated by exmaning the the ratio of CH2Cl2 and 1-octanol in organic phase. The optimum composition of CH2Cl2 and 1-octanol was determined to be 1:1.Based on the extraction of Cs(Ⅰ) by the Calix[4]arene-crown derivatives, the 5 counter-current extraction of Cs(Ⅰ) and the tested elements by NonCalix[4]C6, DecCalix[4]C6, and DodCalix[4]C6 were studied. In all cases of experiments, the extraction percentages of Cs(Ⅰ) were always more than 99%. The experimental and theoretical basis of effective separation of Cs(I) have been provided.