【摘要】：離子液體作為新型綠色溶劑具有可設(shè)計性、寬液程和不揮發(fā)性等獨(dú)特理化性質(zhì),可作為傳統(tǒng)有機(jī)溶劑的優(yōu)良替代品。離子液體的理論研究是實(shí)踐應(yīng)用的前提,而離子液體的基礎(chǔ)物性數(shù)據(jù)對理論研究至關(guān)重要。本文應(yīng)用量子化學(xué)方法對離子液體的分子結(jié)構(gòu)體積參數(shù)r和表面積參數(shù)q進(jìn)行了計算。利用限制性哈特里-福克方法以及密度泛函理論優(yōu)化了離子液體的分子結(jié)構(gòu),然后采用極化連續(xù)介質(zhì)模型計算最優(yōu)分子結(jié)構(gòu)參數(shù)r和q值,進(jìn)而得到12種離子液體分子結(jié)構(gòu)參數(shù)。使用UNIQUAC模型結(jié)合分子結(jié)構(gòu)參數(shù)關(guān)聯(lián)了文獻(xiàn)中含離子液體體系液液相平衡實(shí)驗(yàn)數(shù)據(jù),得到了相應(yīng)的體系UNIQUAC模型參數(shù),計算得到均方根偏差平均值為0.0117,表明計算的離子液體r和q值用于UNIQUAC模型能較好的關(guān)聯(lián)三元體系液液相平衡數(shù)據(jù)。針對目前工業(yè)生產(chǎn)中含低碳醇共沸物難分離的問題,本文采用咪唑類離子液體作為萃取劑進(jìn)行了液液相平衡實(shí)驗(yàn)來探究離子液體對含低碳醇共沸物萃取的可行性。針對低碳醇-水共沸體系,采用1-烷基-3-甲基咪唑雙三氟甲磺酰亞胺鹽([Cnmim][NTf2])為萃取劑,研究了三種水-低碳醇-[Cnmim][NTf2]體系的液液相平衡。針對低碳醇-正庚烷共沸體系,采用[Hmim][OTf]作為萃取劑,研究了三種正庚烷-低碳醇-[Hmim][OTf]體系的液液相平衡。測定了相應(yīng)的液液相平衡實(shí)驗(yàn)數(shù)據(jù)并計算出分配比和分離因子,評估了離子液體的萃取能力并與文獻(xiàn)中的離子液體萃取能力進(jìn)行了對比。本文進(jìn)一步探究了咪唑類離子液體的烷基鏈取代基長度和醇的結(jié)構(gòu)在體系液液相平衡中的規(guī)律。結(jié)合計算的離子液體的結(jié)構(gòu)參數(shù)r和q值,利用NRTL和UNIQUAC模型關(guān)聯(lián)了本文中六組含離子液體的液液相平衡實(shí)驗(yàn)數(shù)據(jù),得到NRTL和UNIQUAC模型參數(shù)。利用UNIFAC模型預(yù)測了正庚烷-低碳醇-[Hmim][OTf]的相行為,與實(shí)驗(yàn)結(jié)果進(jìn)行了比較,評估了UNIFAC模型對含離子液體體系的預(yù)測能力。實(shí)驗(yàn)結(jié)果表明了本文所用的離子液體分離含低碳醇共沸物的可行性。計算得到的離子液體結(jié)構(gòu)參數(shù)、含離子液體體系實(shí)驗(yàn)數(shù)據(jù)和熱力學(xué)模型參數(shù),可用于該類體系的液液相平衡計算及相關(guān)過程的設(shè)計。
[Abstract]:As a new green solvent, ionic liquids have unique physicochemical properties, such as designability, wide liquid range and no volatility, so they can be used as excellent substitutes for traditional organic solvents. The theoretical study of ionic liquids is the premise of practical application, and the basic physical properties of ionic liquids are very important to the theoretical research. In this paper, quantum chemical method is used to calculate the molecular structure volume parameter r and surface area parameter Q of ionic liquids. The molecular structure of ionic liquids was optimized by using restricted Hartley-Focker method and density functional theory, and the optimum molecular structure parameters r and Q were calculated by polarization continuum model. The molecular structure parameters of 12 kinds of ionic liquids were obtained. The experimental data of liquid-liquid equilibrium of ionic liquids in literature were correlated with the UNIQUAC model and the molecular structure parameters, and the corresponding UNIQUAC model parameters were obtained. The average RMS deviation is 0.0117, which indicates that the calculated values of r and Q of ionic liquids can well correlate the liquid-liquid equilibrium data of ternary system with UNIQUAC model. Aiming at the difficult separation of azeotropic compounds containing low carbon alcohols in industrial production, the liquid-liquid equilibrium experiments were carried out with imidazole ionic liquids as extractants to explore the feasibility of extraction of azeotropic compounds containing low carbon alcohols by ionic liquids. In this paper, the liquid-liquid equilibrium of three kinds of water-low alcohol [Cnmim] [NTf2] system was studied by using [Cnmim] [NTf2] as extractant for low carbon alcohol-water azeotropic system. The liquid-liquid equilibrium of n-heptane-n-heptane azeotropic system was studied by using [Hmim] [OTf] as extractant. The liquid-liquid equilibrium of three kinds of n-heptane-low alcohol [Hmim] [OTf] system was studied. The experimental data of liquid-liquid equilibrium were measured and the partition ratio and separation factor were calculated. The extraction ability of ionic liquid was evaluated and compared with that in literature. The length of alkyl chain substituents and the structure of alcohols in the liquid-liquid equilibrium of imidazole ionic liquids were further investigated. Combined with the calculated structural parameters r and Q of ionic liquids, the NRTL and UNIQUAC models were used to correlate the experimental data of liquid and liquid equilibrium of six groups of ionic liquids, and the parameters of NRTL and UNIQUAC models were obtained. The phase behavior of n-heptane-low-carbon alcohol- [Hmim] [OTf] was predicted by UNIFAC model, and compared with the experimental results. The prediction ability of UNIFAC model for ionic liquid system was evaluated. The experimental results show that the ionic liquid used in this paper is feasible for the separation of azeotrope containing low carbon alcohols. The calculated structure parameters, experimental data and thermodynamic model parameters of ionic liquids can be used to calculate liquid-liquid equilibrium and design related processes.
【學(xué)位授予單位】：青島科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O645.1;O642.42

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