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几种大孔硅基超分子识别材料制备及其吸附铯的基础特性研究
Synthesis of a Few Macroporous Silica-based Supermolecular Recognition Materials and Their Adsorption Properties for Cesium
【作者】 陈春梅;
【导师】 张安运;
【作者基本信息】 浙江大学 , 化学工程, 2011, 硕士
【摘要】 合成了三种超分子识别试剂25,27-二(1-烷氧基)杯[4]芳烃-26,28-冠-6(Calix[4]arene-Crown)衍生物:25,27-二(1-丁氧基)杯[4]芳烃-26,28-冠-6(ButCalix[4]C6)、25,27-二(1-己氧基)杯[4]芳烃-26,28-冠-6(HexCalix[4]C6)和25,27-二(1-庚氧基)杯[4]芳烃-26,28-冠-6(HepCalix[4]C6),以元素分析、FT-IR、TG-DSC、ESI-MS和1H NMR对中间产物和目标产物进行了表征,对Calix[4]arene-Crown化合物的合成反应机理进行了分析。探讨了中间体5,11,17,23-四叔丁基-25,26,27,28-四羟基杯[4]芳烃(TBTHC4)的合成工艺条件,考察了各种因素对合成产率的影响,最佳工艺条件确定为:对叔丁基苯酚、NaOH和甲醛的摩尔比=1:0.1:1.5,在二苯醚用量1000mL,于260-C温度下回流5h,经乙酸乙酯重结晶,其产率为66.38%。对目标产物Calix[4]arene-Crown的重结晶工艺进行了研究,考察了不同极性溶剂及其用量对目标产物重结晶的影响。基于固定化和真空活化灌注技术,以大孔Si02-P为载体,合成了三种新型大孔硅基超分子识别材料(Calix[4]arene-Crown/SiO2-P):25,27-二(1-丁氧基)杯[4]芳烃-26,28-冠-6硅基材料(ButCalix[4]C6/SiO2-P)、25,27-二(1-己氧基)杯[4]芳烃-26,28-冠-6硅基材料(HexCalix[4]C6/SiO2-P)和25,27-二(1-庚氧基)杯[4]芳烃-26,28-冠-6硅基材料(HepCalix[4]C6/SiO2-P),以FT-IR、TG-DSC、XRD和BET等手段进行了表征,明确了新型超分子识别材料的复合机理和微观结构。在HN03溶液中,分别考察了酸度和接触时间等因素对大孔硅基超分子识别材料吸附Cs(Ⅰ)及十余种共存金属离子的影响。结果表明:HNO3浓度对Calix[4]arene-Crown/SiO2-P吸附Cs(Ⅰ)的性能有较大影响。随着HN03浓度的增加,Cs(Ⅰ)的分配系数Kd均明显增加,随后Kd又明显降低,说明在较低的酸度条件下,Calix[4]arene-Crown/SiO2-P对Cs(Ⅰ)的识别与配位作用占主导地位,在高酸度条件下,Calix[4]arene-Crown/SiO2-P与HN03之间以氢键方式相互缔合作用占主导地位,二者在0.4-5.0M HN03浓度研究范围内呈现竞争反应。ButCalix[4]C6/SiO2-P、HexCalix[4]C6/SiO2-P和HepCalix[4]C6/SiO2-P对Cs(Ⅰ)的最佳吸附酸度分别为2.OMHNO3、3.OMHNO3和2.OMHNO3,被试验的金属离子除Rb(Ⅰ)和Pd(Ⅱ)外,均表现为弱吸附或基本不被吸附。三种新型材料在3.0MHNO3对Cs(Ⅰ)的吸附能力为:HexCalix[4]C6/SiO2-P>HepCalix[4]C6/SiO2-P>ButCalix[4]C6/SiO2-P.与真实高放废液(HLLW)的酸度3.0M HNO3相比,HexCalix[4]C6/SiO2-P的最佳吸附酸度亦为3.OMHNO3,这对有效分离Cs(Ⅰ)是有利的,可不经稀释直接进行分离。故HexCalix[4]C6/SiO2-P有望用于从HLLW中吸附分离发热元素Cs(Ⅰ)。
【Abstract】 It is known that the supramolecular recognition agents have high selectivity for Cs(Ⅰ), one of the main heat emitting nuclides. For effective partitioning of Cs(Ⅰ) from highly level liquid waste (HLLW), the derivatives of 25,27-bis(1-alkyloxy)calix[4]arene-26,28-crown-6(Calix[4]arene-Crown): 25,27-bis(1-butyloxy)calix[4]arene-26,28-crown-6(ButCalix[4]C6), 25,27-bis(1-hexyloxy)calix[4]arene-26,28-crown-6(HexCalix[4]C6), and 25,27-bis(1-hepxyloxy)calix[4]arene-26,28-crown-6(HepCalix[4]C6), were synthesized. The relevant intermediates and target products were characterized by elemental analysis, FT-IR, TG-DSC, ESI-MS and 1H NMR. The synthetic mechanism of Calix[4]arene-Crown was discussed.The synthesis of an intermediate product,5,11,17,23-tetra-butyl-25,26,27,28-tetrahydroxycalix[4]arene(TBTHC4), was examined. The results showed that as the molar ratio of p-tert-buthypheno, NaOH, and formaldehyde solution was 1:0.1:1.5, refluxing for 5h in diphenyl ether at 260℃, and recrystallizing with ethyl acetate, the yield of the TBTHC4 product was 66.38%.The novel supramolecular recognition materials, ButCalix[4]C6/SiO2-P, HexCalix[4]C6/SiO2-P and HepCalix[4]C6/SiO2-P, were synthesized. It was done through impregnation and immobilization of the relevant supramolecular recognition agent into the pores of the macroporous SiO2-P particles support. The composite mechanism and micro-structures of the novel supramolecular recognition materials were understood by characterization using FT-IR, TG-DSC, XRD and BET.The adsorption of Cs(Ⅰ) and more than 10 typical elements onto the ButCalix[4]C6/SiO2-P, HexCalix[4]C6/SiO2-P and HepCalix[4]C6/SiO2-P materials were investigated at 25℃. It was carried out by examining the effects of contact time and the HNO3 concentration in the range of 0.4-5.0 M. ButCalix[4]C6/SiO2-P, HexCalix[4]C6/SiO2-P and HepCalix[4]C6/SiO2-P showed excellent adsorption ability and high selectivity for Cs(Ⅰ) over all the tested metals except Rb(Ⅰ) and Pd(Ⅰ Ⅰ). The complexation of Cs(Ⅰ) with the supramolecular recognition materials as well as the association of the supramolecular recognition materials with HNO3 through hydrogen bonding were two competitive reactions. The optimum HNO3 concentration in the adsorption of Cs(Ⅰ) was 2.0 M HNO3 for ButCalix[4]C6/SiO2-P and HepCalix[4]C6/SiO2-P as well as 3.0 M HNO3 for HexCalix[4]C6/SiO2-P. The adsorption ability of three novel materials for Cs(Ⅰ) in 3.0 M HNO3 was as follows: HexCalix[4]C6/SiO2-P>HepCalix[4]C6/SiO2-P>ButCalix[4]C6/SiO2-P. It is known that the HNO3 concentration in genuine HLLW is around 3.0 M, it is therefore of great beneficial to application of HexCalix[4]C6/SiO2-P in the separation of Cs(Ⅰ) from HLLW.
【Key words】 Synthesis; Calix[4]arene-Crown; Macroporous silicon-based supramolecular recognition materials; adsorption; Cs;