【作者】 于环洋；

【导师】 崔占臣；

【作者基本信息】 吉林大学 ， 高分子化学与物理， 2014， 博士

【摘要】 由于芳香烃和链烷烃组成物相近的沸点以及混合物中恒沸组成的存在，芳香烃和链烷烃的分离一直是分离、吸附领域研究的难点和热点之一。传统的分离方法是利用环丁砜、N-甲基吡咯烷酮、N-甲酰基吗啉等有机溶剂对烃类混合物进行液液萃取和抽提蒸馏。由于这些溶剂的沸点均较高，再生处理时需要以蒸汽的形式从回收器的顶端返回到脱单塔底部，导致了成本的增加和大量能源的消耗。还有一部分溶剂残留在非芳烃相中，这些溶剂的回收需要大量的水洗和能耗。另外，两种分离方法对于质量浓度低于20%的芳香烃均达不到很好的分离效果。近年来，离子液作为有希望替代传统溶剂的一种新的分离溶剂被广泛的研究。然而离子液也存在着粘度高；价格高；有腐蚀性；在湿空气和水中不稳定等诸多问题，难以实现工业化。膜渗透汽化技术是基于混合物各组成在膜中不同的溶解和扩散能力对芳香烃/链烷烃混合物进行分离的一门新兴技术。早期的渗透汽化膜材料，如聚乙烯、聚丙烯等，尽管成膜性好、通量大，但是易于溶胀，选择性欠佳。而芳香族聚氨酯、聚醚酰胺和聚苯并噁唑等膜材料，尽管不易被普通溶剂溶解，获得了较高选择系数，但存在着通量小、操作条件苛刻的缺点。聚苯乙烯材料由于其优良的机械性能、良好的热稳定性和化学稳定性，在色谱、吸附、离子交换树脂以及印记高分子领域被广泛地应用。将改性聚苯乙烯材料用于芳香烃/链烷烃的分离，具有成本低，回收方便，操作简单的优势。与传统的分离技术相比，改性交联聚苯乙烯球分离芳香烃/链烷烃技术以其对芳烃的选择性溶胀为基础，主要利用苯乙烯侧链上的苯环与芳烃之间较强的π-π作用，在聚苯乙烯侧链上引入极性基团，使得芳烃仍然能溶胀于聚苯乙烯中，而链烷烃则不能溶胀于聚苯乙烯，从而提高改性交联聚苯乙烯的芳烃选择性。本论文的主旨是设计和制备可应用于芳香烃/链烷烃分离的改性聚苯乙烯材料。我们制备了几种不同结构和组成的聚苯乙烯材料，并研究了其对多种芳香烃/链烷烃的分离效果。在本论文第一章，我们简要介绍了芳烃/链烷烃分离的主要方法，并介绍了聚合物极性修饰的主要方法。在此基础上，提出了本论文的设计思想及主要内容。在本论文第二章，我们设计合成了磺酰化低分子量的聚苯乙烯，采用核磁、红外、元素分析等测试手段对产物进行了详细的表征。将其用于甲苯/正庚烷溶液萃取，结果发现甲苯分配系数和选择性系数均随磺化比例的增大明显提高。该材料表现出较好的热稳定性，可以重复使用。在本论文的第三章，我们制备了酯基、酰胺基以及砜基修饰的交联聚苯乙烯球。考察了各种影响球粒径的因素以及修饰基团的含量对树脂球溶胀能力和选择性能的影响。发现酰胺基修饰交联聚苯乙烯的溶胀率较大，在43-54%的范围内。后磺化法制备的砜基修饰交联聚苯乙烯球具有较高的选择因子。比较用于改性砜基的三种磺化剂，发现其反应活性为苯磺酰氯〉对甲苯磺酰氯〉甲磺酰氯。对甲苯磺酰氯与苯磺酰氯改性树脂球的选择因子均高于甲基磺酰氯磺化聚苯乙烯球。当甲苯/正庚烷喂料中甲苯含量为的13wt.%时，溶胀率为24%，甲苯的选择因子为3.27。在本论文的第四章，我们通过碳酸钙晶须占位及刻蚀的方法制备了具有微米级通道结构的交联聚苯乙烯球，对磺化后交联聚苯乙烯中硫元素分布情况进行了表征，发现具有通道结构的树脂球砜基分布更均匀。与不具有通道结构的交联聚苯乙烯球相比较，通道结构交联聚苯乙烯球达到饱和溶胀的时间明显缩短。该材料用于苯/正己烷混合物分离，溶胀率31%，分离因子为6.37。更多还原

【Abstract】 The separation of aromatics hydrocarbons from aliphatic hydrocarbon ischallenging due to their close boiling points and azeotropes formation. The traditionalseparation methods are extraction and extractive distillation with organic solventssuch as N-formyl morpholine, N-methyl pyrrolidone or sulfolane. The regeneration ofsolvents needs to remove them from the extract and raffinate phase, partial residualsolvents in aliphatic phase needs to be removed using large amounts of water, whichcause an additional investment and energy consumption. In addition, two kinds ofmethods can not obtain high selective factors for feeds with low aromatic content(<20%). Recently, ionic liquids, which are considered to be promising as replacementsfor the aforementioned organic solvents, have been studied widely. However, mostionic liquids have unfavorable chemical properties which disable their use on biggerscales in industries. These limitations are mainly due to instability as a result ofcorrosiveness and moisture instability as well as insolubility in water. Anotherdisadvantages of ionic liquids is its high viscosity and high price. Permeability is anemerging method of aromatic/aliphatic separation. Permeability through polymericmembranes is mainly dependent on solubility and diffusion differences between thecomponents of mixture. The membranes based on polyethylene, polypropylene havedisplayed good film-forming ability and large flux, but swelling of membrane insolvents and low selectivity have been some problems difficult to be solved. Althoughthe membranes based on aromatic polyurethane， polyether amide and polybenzoxazole can not be dissolved by common solvents and displayed highseparation factors, the major roadblocks in pervaporation are the low flux and harshoperation conditions. For all these reasons, the industry has always been eager to lookfor a viable alternative to the conventional aromatics/aliphatics separation processes.Polystyrene have excellent mechanical properties, good chemical and thermalstability. Their excellent performances provide wide applications in chromatography,adsorption, ion-exchange resins and imprinted polymer fields. As a type of absorbentfor potential separation of aromatics/aliphatics, polystyrene has a lower raw materialcost, simple operation and recovery. Compared with traditional separation methods,the separation of aromatics/aliphatics using polystyrene based on selective swelling inaromatic hydrocarbons, mainly depends on the strong π-π interaction between thephenyl group of the styrene and aromatics. In addition, due to the introduction ofpolar groups, polystyrene still can swell in aromatics, but can not do in aliphatics.In this dissertation, we aim at the design and preparation of polystyrene modifiedwith polar groups that can be used on the separation of aromatics/aliphatics. Severalkinds of polystyrene with different structure and composition have been prepared andthe separation effects on a variety of aromatic/aliphatic hydrocarbons have beenstudied.In chapter1, we have made a brief introduction of separation methods ofaromatics/aliphatics; then we reviewed the methods of modification of polystyrene.In chapter2, we have prepared the low molecular weight sulfonate polystyrene.Their properties were fully characterized by nuclear magnetic resonance, Fouriertransform infrared spectroscopy and elemental analyses. Modified polystyrene wasapplied to extract toluene from toluene/n-heptane solution.The results indicates thatwith increasing content of sulfone groups, the distribution coefficient and selectivefactor of toluene obviously increased. This kind of material displayed excellentthermal abilities and good regeneration capacities.In chapter3, we have prepared cross-linked polystyrene beads modified with ester,amide or sulfone groups. The influencing factors of particle size of beads were studied and the effect of modified group content on swelling ratio and selective factor wasobserved. The results indicate that the crosslinked polystyrene beads modified withamide groups displayed high swelling ratios in the range of43-54%. The beadsmodified with sulfone groups which was prepared using post-sulfonylation revealedhiger separation factors. A comparison of the experiments with three kinds ofsulfonating agent led to the conclusion that the order of reactivity of sulfonatingagents is：benzenesulfonyl chloride〉4-toluene sulfonyl chloride〉methanesulfonylchloride. The separation factors of sulfonated polystyrene with4-toluene sulfonylchloride and benzenesulfonyl chloride were also higher than that of methanesulfonylchloride. The swelling ratio was24%and the separation factor was3.27when thetoluene content was13wt.%in the feed mixture.In chapter4, the cross-linked polystyrene beads with channels were successfullyprepared by occupation and etch of CaCO3whiskers. These beads were sulfonated andthe distribution of sulfur was characterized by EDAX. Results indicate that thechannel structure facilitated the uniform distribution of sulfone groups. Comparedwith that of nonchannel polystyrene beads, the saturated swelling time of channelbeads obviously decreased. These beads were applied to separate benzene/hexane andresults indicate that swelling ratio was31%and selective factor was6.37.更多还原