疏水性离子液体的设计合成及应用基础研究

【作者】 李江纳；

【导师】 瞿广飞；

【作者基本信息】 昆明理工大学 ， 环境工程， 2014， 硕士

【摘要】 近年来,随着工业和社会的发展,所产生的环境问题越来越严重,并且得到社会各界的广泛关注,尤其是大气污染所导致的雾霾天气,已经给人们的生产生活和身体健康带来一系列严重问题,不仅制约着社会经济的发展,而且危害到人类的可持续发展,因此大气污染控制势在必行,其中又以有毒有害气体成分最难处理。大气污染中磷、硫的污染由来已久,也已经有一些治理方法,但是这些方法多多少少都有些问题,或成本很高,或效果不理想,或腐蚀设备等等。近年来,离子液体开始受到人们的广泛关注,其中一些是关于将离子液体用于气体吸收净化的应用研究。离子液体由于其自身的特性引起了人们广泛的关注,作为一种新型有机溶剂,可以通过合成的单体来控制离子液体的阴阳离子,进而控制其性质和用途。这篇论文拟在寻找一种或几种疏水性离子液体与水形成双液相,再配以金属离子形成双液相催化氧化净化体系。因此,我们总结了适合本实验的疏水性离子液体的设计原则,并将其应用于PH3和H2S的净化实验。主要研究结果如下：(1)适合本实验的疏水性离子液体的设计合成原则我们所需要的疏水性离子液体首先要有很好的疏水性,其次对需要净化的两种气体以及氧气有尽可能大的溶解度,根据这些因素提出了具体的原则：a、影响离子液体疏水性的因素有官能团种类与数量,阴离子种类(这是决定性因素,决定着离子液体的亲水性、疏水性),阳离子侧链长度等因素。在已知的离子液体中只有极少数是疏水性离子液体,决定其疏水性的阴离子种类,比如FP6、BF4、[Tf2N]-等,同时增大离子液体的不对称性可以增强其疏水性,此外增加阳离子上所连接侧链的碳原子数也可以增强其疏水性；b、使气体在离子液体中的溶解度尽可能大：根据前人的实验结果可知1)气体在离子液体中的溶解度与普通溶剂相同,都是随温度的升高而减小,压力升高会使其溶解度增大。但是H2在离子液体中的溶解度随温度的升高而增大,且几乎不随压强变化而变化。2)离子液体的极性也会影响气体在其中的溶解度,气体在离子液体中溶解度一般随着离子液体极性的增大而减小。3)气体在离子液体中的溶解度受其阴离子影响较大,而受阳离子的影响较小,并且随其阴离子体积的增大而增大。4)此外离子液体的熔点和黏度也会影响其对气体的溶解能力,要使其熔点和黏度尽可能低。综合上述因素,我们选择了阴离子为[Tf2N]-的离子液体作催化剂。(2)本实验合成了[Hmim]PF6、[Bmim][Tf2N]、[Hmim][Tf2N]、[Omim][Tf2N]、[eamim]PF6和[Amim]PF6几种离子液,对他们进行了红外和核磁表征分析,并进行了热稳定性分析,结合这些结果并根据合成原则和溶解度的大小,将吸收液最终定为[Hmim][Tf2N]离子液体。(3)首先通过实验发现[][Hmim][Tf2N]离子液体本身对H2S、 PH3没有净化效果。此后,将多种金属离子与Hmim][Tf2N]离子液体在磷酸三丁酯的作用下螯合,测定他们对磷化氢、硫化氢的净化效果,发现钯基离子液体的催化效果最好,因此将吸收液定为钯基[Hmim][Tf2N]离子液体。(4)钯基离子液体/水形成的双液相体系对磷化氢、硫化氢的净化效果很明显,净化效率能长时间维持在99%以上。钯基[Bmim][Tf2N]离子液体净化磷化氢的最优反应条件为：混合气体流速为110mL/min,反应温度为40℃,进口处磷化氢气体浓度为1000ppm,取10mL吸收液(钯基[Bmim][Tf2N]和水的体积比为1：1),[Bmim][Tf2N]:PdCl2:磷酸三丁酯摩尔比为1：0.075：1；钯基[Bmim][Tf2N]离子液体净化磷化氢的最优反应条件为：11OmL/min,反应温度为40℃,进口处磷化氢气体浓度为1000ppm,取10mL吸收液(钯基[Hmim][Tf2N]和水的体积比为1：1),[Hmim][Tf2N]:PdCl2:磷酸三丁酯摩尔比为1：0.068：1。所做实验中钯基[Hmim][Tf2N]对H2S的净化效果最好的实验条件为：气体流量为11OmL/min,氧含量为9.09%,反应温度为50℃,添加6mL吸收液(钯基[Hmim][Tf2N]和蒸馏水体积比为1：1),[Hmim][Tf2N]:PdCl2:磷酸三丁酯摩尔比为1：0.05：1。因为整个催化氧化净化硫化氢的时间很短,最好的仅能维持在1h以内,所以没有进一步寻找最优条件。通过实验研究发现影响净化效率的因素与净化效率并不成正比关系,比如随着催化剂添加量的增大,净化效率先增大后降低,所有这些因素均表现出相同规律。(5)通过对催化剂溶液进行鼓氧18h,再生后的吸收液净化效率有着明显上升,说明Pd-IL催化剂具有可再生性；(6)对钯基[Hmim][Tf2N]催化氧化磷化氢机理进行初探,猜想合成的催化剂的三种物质生成配位体而不发生化学反应,起到催化氧化效果的是PdCl2。更多还原

【Abstract】 In recent years, with the development of industry and society, environmental problems that received extensive attention from all sectors of society are becoming more and more serious. Especially the haze weather caused by the air pollution, has brought a series of serious problems to people’s production and life and health. It not only restricts the development of social economy, but also harms to the sustainable development of human beings. So the air pollution must be controlled, and it is hardest to deal with toxic or harmful gases. Phosphorus pollution and sulfur pollution in air pollution have kept for a long time. Although there are some ways to deal with these problems, the treatment methods may be deficient, such as high cost、inefficient and equipment corrosion.Ionic liquids are paid close attention in recent years, and some of Ionic liquids are used in the gas absorption purification. As a new type of organic solvent, properties of ionic liquids have aroused widespread concern, synthesize monomer can control the cation and anion of ionic liquid so that it can control their properties and uses. This paper intends to find one or severalhydrophobic ionic liquid to form a two liquid phase with water, then to form two liquid phase catalytic oxidation system with the help of metal ions. The design principles of hydrophobic ionic liquid have been summarized for the experiment need, and the hydrophobic ionic liquid will be used in the purification experiment of PH3and H2S. The main research results are as follows:(1) The design principle of synthesis hydrophobic ionic liquid for the experimentFirstly, hydrophobic ionic liquids need good hydrophobic. Then solubility of it can be as lagre as possible for PH3、H2S and O2. According to these factors, specific principles are chosen:a、The ionic liquid hydrophobic may be affected by some factors. These factors include the species and quantity of functional groups、anion species which determines thehydrophilic, hydrophobic ionic liquid as a decisive factor、cationic side chain length and so on. Only a few of known ionic liquid are hydrophobic ionic liquids, their hydrophobic are decided by anion species, such as FP6， BF4[Tf2N] and so on. Both increasing the asymmetry of ionic liquid and increasing the side chain carbon atoms connected with the cation can enhance the hydrophobicity.b、 Making gas solubility in ionic liquids as large as possible:according to the previous experimental results,it shows that:1) the solubility of gas in ionic liquid will decrease with increasing temperature and enlarge with increasing pressure, so do the common solvents. But the H2solubility in ionic liquids increases with increasing temperature and changes a little with the pressure changes.2) The polarity of ionic liquids will affect the solubility of gas in ionic liquid, generally it decreases with the increasing of ionic liquids polarity.3) Anionic has an greater impact on the solubility of gas in ionic liquid than cationic, when anion volume expands, the solubility of gas in ionic liquid will enlarge.4) The melting point and viscosity of the ionic liquid can also affect the solubility of gases, so the melting point and viscosity should be as low as possible.Comprehensive above factors, the anionic [Tf2N] ionic liquid is chosen as catalyst.(2)[Hmim]PF6,[Omim]PF6,[Bmim][Tf2N],[Hmim][Tf2N],[Omim][Tf2N],[eamim]PF6an d [Amim]PF6have been synthesized in this experiment, these ionic liquid are analyzed by IR、NMR and TG. According to the principle of synthesis、size of the solubility and analysis data,[Hmim][Tf2N] ionic liquid is the absorption liquid of this experiment eventually.(3)[Hmim][Tf2N] ionic liquid cann’t help to purify H2S and PH3through the experiment. Under the action of tributyl phosphate,[Hmim][Tf2N] ionic liquid will chelate various metal ions. Measuring the purification effect of phosphine, hydrogen sulfide, the results show that only palladium based ionic liquids own the best catalytic effect. So palladium based [Hmim][Tf2N] ionic liquid will be the appropriate choice of absorption solution.(4) Purification effect of phosphine and hydrogen sulfide will be very obvious since Palladium-based ionic liquid/liquid water forms two-liquid-phase system. The purification efficiency can be more than99%for a long time. Optimal reaction condition for purification of phosphine with the help of Palladium-based [Bmim][Tf2N] ionic liquid should be:Mixed gas flow rate is110mL/min, the reaction temperature is40℃, phosphine gas in entrance,its concentration is1000ppm. Drawing lOmL absorption liquid (Palladium-based [Hmim][Tf2N] and water volume ratio is1:1),[Hmim][Tf2N]:PdCl2:phosphoric acid butyl ester three molar ratio of1:0.075:1; Optimal reaction condition for purification of phosphine with the help of Palladium-based [Bmim][Tf2N] ionic liquid should be: Mixed gas flow rate is110mL/min, the reaction temperature is40℃, phosphine gas in entrance,its concentration is1000ppm. Drawing10mL absorption liquid (Palladium-based [Hmim][Tf2N] and water volume ratio is 1:1),[Hmim][Tf2N]:PdCl2:phosphoric acid butyl ester three molar ratio of1:0.068:1. The best condition for the highest efficiency of H2S purification with [Hmim][Tf2N] should be:gas flow rate is110mL/min; the oxygen content is9.09%; the reaction temperature is50℃; adding6mL absorption liquid (Palladium-based [Hmim][Tf2N] and distilled water volume ratio of1:1),[Hmim][Tf2N]:PdCl2: phosphoric acid butyl ester three molar ratio of1:0.05:1. It is very short for Hydrogen sulfide’s catalytic oxidation and just keeps within lh so that it is hard to do some further researches about best condition.From these experiments, it shows that various impact conditions should keep in a certain range, for example, with the increase of amount of catalyst, the purification efficiency will increase first and then decrease to a numerical value. All these factors showed the same pattern.(5) Blowing oxygen into catalyst solution for18h, purification efficiency of regenerated absorption increases significantly, the result shows that Pd-IL catalyst has renewability.(6) Making a preliminary study on the catalytic oxidation of phosphinepalladium based [Hmim][Tf2N] mechanism, it is found that three kinds of material for catalyst may form ligand instead of reacting with each other and the PdCl2plays the role of catalytic oxidation.更多还原