【作者】 王琦；

【导师】 杨延钊；

【作者基本信息】 山东大学 ， 无机化学， 2021， 博士

【摘要】 由于在硫化促进剂、络合剂、橡胶防老剂、高速光敏热成像材料等方面均有广泛应用,咪唑-2-硫酮已受到相当的关注。然而,罕有可用作多用途催化剂的1,3-二取代咪唑-2-硫酮用于水相中金属萃取的报道。中性萃取剂1-辛基-3-甲基咪唑-2-硫酮与1-丁基-3-甲基咪唑-2-硫酮由于熔点低、水溶性差、不易挥发,在萃取贵金属方面很有潜力。从绿色化学与绿色化工的意义上来说,获得一种可用于预筛选铂族金属萃取剂的简单实用方法具有重要意义。量子化学由于可用于在无需实际合成、大幅节约成本的情形下预筛选大量可能具有多位点的萃取剂,是一种非常有前途的理论工具。尽管近年来出现了一系列溶剂萃取方面的计算研究,有关铂族金属萃取尤其是以环保的离子液体为研究对象的研究工作仍然相当有限。基于上述研究背景,本论文的主要研究内容主要分为两方面,即咪唑硫酮萃取铂的相关研究与量子化学在铂族金属萃取中应用的相关研究。具体内容如下:1.OMImT从盐酸介质中分离铂本部分中,我们合成了一种不易挥发、低熔点的中性萃取剂1-辛基-3-甲基咪唑-2-硫酮(OMImT),并基于其疏水性好、粘度低的优点将其首次用于通过无分散剂沉淀法于盐酸介质中分离铂。首先,我们通过对无分散剂沉淀法和以环己烷为分散剂的液液萃取法从OMImT用量及振荡时间对分离铂的影响的角度进行比较,评价了二者分离铂的性能。继而,探究了一些分离铂的影响因素(如相比、HCl浓度、H+浓度及Cl-浓度)。其后,我们首次提出了 OMImT分离Pt(Ⅳ)的机理为一种特殊的中性络合机理,并通过量化计算与实验手段相结合的方式证明了该机理。最后,我们通过动力学拟合法研究了该体系的动力学。2.BMImT从盐酸介质中萃取铂本部分中,我们合成了一种不易挥发、低熔点的中性萃取剂1-丁基-3-甲基咪唑-2-硫酮(BMImT),并将其首次用于通过以氯仿为分散剂的液液萃取法于盐酸介质中分离铂。此外,我们探究了 BMImT/氯仿体系萃取Pt(Ⅳ)的影响因素(如BMImT浓度、相比、HCl浓度及Cl-浓度)。其后,我们首次提出了BMImT分离铂的机理为一种特殊的中性络合机理,并通过量化计算与实验手段相结合的方式证明了该机理。我们还研究了该体系的动力学。3.通过量化ESP-ALIE分析识别可能具有多位点萃取剂的配位原子本部分中,我们探讨了一种对于识别可能具有多位点的铂族金属萃取剂的活性位点简单可行且在离子液体溶剂环境中也同样适用的理论工具——ESP-ALIE分析(即结合静电势分析与平均局部离子化能分析)的应用。我们评价了五种泛函(B3LYP、CAM-B3LYP、M06、M06-2X 及 ωB97X-D)与两种溶剂模型(SMD与SMD-GIL溶剂模型)通过ESP-ALIE分析在识别可能具有多位点萃取剂的配位原子方面的表现。首先,对于由可萃Pd(Ⅱ)的两种中性萃取剂及两种离子液体萃取剂溶于离子液体稀释剂组成的测试集,我们对其ESP-ALIE分析对于配位位点识别的可靠性由晶体学证据进行了验证。然后,我们对一种溶于离子液体稀释剂的中性萃取剂萃Pt(Ⅳ)的配位原子利用ESP-ALIE分析进行预测后,探究了萃取Pt(Ⅳ)的一些影响因素(如萃取剂、HCl及Cl-浓度)及机理,并首次报道了其萃合物的单晶数据,通过该实验证据验证了从ESP-ALIE角度作出的理论预测。4.阴离子为[NTF2]-的UCST型离子液体的阳离子静电势与上临界共溶温度关系的量化研究本部分中,我们探究了 13种在萃取中潜力较大的、阴离子为[NTF2]-的UCST型离子液体实例中阳离子的静电势与上临界共溶温度的相关关系,并首次系统评价了 4种泛函(B3LYP、M06-2X、ωB97X-D及B3PW91)的表现。更多还原

【Abstract】 Imidazole-2-thiones have attracted considerable attention due to its wide applications in vulcanization accelerators,complexing agents,rubber antioxidants,and high-speed photothermographic materials,etc..However,few researches on the removal of metals from aqueous solutions have been reported by 1,3-disubstituted imidazole-2-thiones,which are a kind of versatile catalysts.1-octyl-3-methylimidazole-2-thione and 1-butyl-3-methylimidazole-2-thione are promising neutral sulfur-bearing extractants for noble metal due to its bad solubility in water,low melting point and negligible vapor pressure.In the sense of green chemistry and green engineering,quantum chemistry is a potential tool,as it can be utilized to prescreen large numbers of possible multisite extractants at low cost without the difficulties of laboratory synthesis.In recent years,a series of computational investigations on solvent extraction have appeared.However,little attention has been paid to the computational research studies on platinum group metal extraction,especially for those taking environmentally benign ionic liquids as solvents.Based on the above research background,the main research contents of this paper are mainly divided into two parts,namely,the research on the extraction of platinum by imidazolithione and the research on the application of quantum chemistry in platinum group metals extraction.The specific content is as follows1.Removal of platinum(Ⅳ)from hydrochloric acid medium with OMImTIn this section,1-octyl-3-methylimidazole-2-thione(OMImT),a neutral sulfur-bearing extractant with low melting point and negligible vapor pressure,was synthesized and first utilized for the removal of Pt(Ⅳ)from hydrochloric acid medium by disperser-free precipitation owing to its excellent hydrophobicity and low viscosity.Estimation for the removal performance of Pt(Ⅳ)by disperser-free precipitation,in comparison with that by liquid-liquid extraction with disperser cyclohexane,as conducted on the effects of the dosage of OMImT and vibration time Subsequently,variable influence factors on the removal of Pt(Ⅳ)(e.g.phase ratio,HCl concentration,H+concentration and Cl-concentration)were also explored Afterwards,the removal mechanismof Pt(Ⅳ)with OMImT was first proposed and evidenced to be a special neutral complexing mechanism via a combination of quantum-chemical calculations and experimental measurements.At last,kinetic datawere analyzed by kinetics fitting methods2.Extraction of platinum(Ⅳ)from hydrochloric acid medium with OMImTIn this section,1-butyl-3-methyl imidazole-2-thione(BMImT),a neutral sulfur-bearing extractant with low melting point and negligible vapor pressure,was synthesized and first utilized for the extraction of Pt(Ⅳ)from hydrochloric acid medium by liquid-liquid extraction with disperser chloroform.Subsequently,variable influence factors on the removal of Pt(Ⅳ)(e.g.BMImT concentration,phase ratio,HCl concentration and Cl-concentration)were also explored.Afterwards,the removal mechanismof Pt(Ⅳ)with OMImT was first proposed and evidenced to be a special neutral complexing mechanism via a combination of quantum-chemical calculations and experimental measurements.At last,kinetic datawere analyzed by kinetics fitting methods.3.ESP-ALIE analysis as a theoretical tool for identifying the coordination atoms of possible multi-site extractantsIn this section,we assessed the performances of five functionals(B3LYP,CAMB3LYP,M06,M06-2X,and ωB97X-D)and two solvation models(the SMD and SMD-GIL models)for identifying the coordination atoms of possible multisite extractants by ESP-ALIE analysis(i.e.,a combination of electrostatic potential analysis and average local ionization energy analysis).First,for the test sets consisting of two neutral extractants and two ionic liquid extractants in ionic liquid solvents for Pd(II)extraction,the reliability of ESP-ALIE analysis for complexation site identification was validated by the crystal evidences.Subsequently,to provide data for the predictive ability of ESP-ALIE analysis,variable influence factors(e.g.,extractant concentration,HCl concentration,and Cl-concentration)and mechanism on the Pt(Ⅳ)extraction with a neutral extractant in ionic liquid diluents were explored.The extracted complex Pt(BMImT)2Cl4,whose single-crystal data were first reported herein,validated the theoretical forecast from the ESP-ALIE point of view.4.Theoretical study on the relationship between the ESP of UCST-type ionic liquid cations with[NTF2]-and theupper critical solution temperatureIn this section,we investigated the relationship between ESP and upper critical temperature of 13 UCST ionic liquids cations with[NTF2]-,and systematically evaluated the performances of four functional(B3LYP,M06-2X,ωB97X-D and B3PW91).更多还原