【作者】 刘剑；

【导师】 董红星；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2005， 硕士

【摘要】 苯是一种重要的有机化工原料,广泛地应用于农药、医药、染料和有机合成工业等行业,因而,对其纯度要求很高且市场需求量极大的,因此能够有效地制取适合市场需求的苯产品具有极大的社会意义。苯主要来源于煤化工和石油化工,因其来源不同所得的粗苯中芳烃的含量有所不同,一般在40%～90%范围内。其余为非芳烃如烷烃、含氧化物、含硫化物、含氮化物等。其中烷烃杂质主要是环已烷、正庚烷和甲基环已烷等,占杂质总含量的90%以上。精制苯的纯度为99.9%据报道,苯与正庚烷之间的相对挥发度仅为0.962。而且,相对挥发度随着杂质含量的减少而减少,因此一般的精馏方法难以将苯中的烷烃完全去除。 为获得高纯度苯去除苯中的烷烃杂质,学术界开展广泛地讨论,文献报道可用NMP复合溶剂（含水的N-甲基吡咯烷酮）或DMF（N、N-二甲基甲酰胺）作为溶剂进行萃取精馏分离。但这两种方法都存在溶剂用量大,能量消耗大,板效率低等缺点,使其应用受到了限制。因此,本文提出DMF溶剂加盐萃取精馏去除苯中的烷烃等杂质。本文是以正庚烷—苯非极性体系为例进行研究的。 加盐萃取精馏集萃取精馏与溶盐精馏的优点于一身而提出的一种新型特殊精馏方法,已引起学术界的高度重视。它是将盐溶于萃取剂,当加入到待分离溶液中时,由于盐与溶液各组分之间的相互作用不同而引起各组分之间相对挥发度等参数的改变,从而达到分离的目的。加盐萃取精馏的优点体现于:一、利用溶盐提高欲分离组分之间相对挥发度的突出性能,可克服纯溶剂效能差、用量大的缺点;二、利用萃取精馏溶剂使液体回收循环方便,工业上易于实现的优点,克服溶盐精馏时盐是固体回收输送困难等缺点,即改进了溶剂效果减少了溶剂比,使用十分方便,具有独特的优点和效能。因此加盐萃取精馏是一种极有应用前景的分离技术。 加盐萃取精馏已成功应用于分离醇—水、酯—水等,而对于分离非极性体系的研究报道较少,目前仅有清华大学的雷志刚博士等人用DMF、ACN溶剂加盐作为混合溶剂萃取精馏分离C₄组分等较少的体系,采用加盐萃取精馏分离苯与正庚烷这一非极性体系至今尚未报道。本文采用DMF加KSCN萃取精馏分离苯中低含量正庚烷取得了良好的分离效果。这既是探索去除苯中低含量正庚烷新的分离方法的一种尝试,又为加盐萃取精馏分离非极性体更多还原

【Abstract】 The benzene is a kind of important organic industrial chemicals, and widely apply to the trades , such as agriculture chemical , medicine , dyestuffs and organic synthesis industry ,etc. it has very high expectations for its purity and the great market demand, So we can make and fetch the benzene products suitable for market demand economically and have great social effects.The benzene stems from the coal industry and petroleum chemical industry mainly, it is different to some extent because the content of the coarse hydrocarbon, generally inthe ranges of 40%-90%, the others for aromatic hydrocarbon, including alkane and hydrocarbon,the sulphides,the nitrogen thing,etc. which is mainly alkane and hydrocarbon of cyclohexane,n-heptane and methy-cyclobexane,which is accounted for more than 90% of the total content of impurity.It is reported that the relative volatility is only 0.962 between benzene and n-heptane and relative volatility reduce too with reduction of impurity content, so it is difficult to separate at all alkane hydrocarbon in benzene general rectification method .It was widely discussed of getting rid of hydrocarbon and impurity of benzene for obtain high purity benzene by the academia.It was reported that the . complex solvent of NMP, or DMF regards as solvent rectification. But these two kinds of methods both have some shortcoming of solvent great consumption, the energy consumption , the efficiency low of the board, which make its application limited, then in the text we propose the solvent DMF with salt to extract rectification getting rid of hydrocarbon impurity from benzene.The extract rectify with salt is a kind of new-type special rectify method which incorporates extracting rectify and dissolving salt rectify into an organic whole and was caused the great attention by the academia. It is the extract solvent of dissolving salt in advance,while the exetract solvent is joining to the solution of waiting to separate The salt and solution every interaction of group is different,and that the solvent component of every group of relative volatility is caused changes,thus the goal of separating is achieved.Its advantage reflect on 1. the salt dissolved can improve the separate group to relative volatility and overcome the shortcoming of bad efficiency,great consumption etc.2.It is convenient of the liquid to retrieve circulation.The advantages is easy to realize on industry,it overcomes the shortcomings of the solid salt of retrieve and sent,etc.Promptly,it improves the solvent result and reduces solventratio,convenient to use.unique advantage and efficiency. So the extract rectify with salt is a kind separation technology of extraordinary application prospects.The extract rectification with salt is succeed in separating alcohol - water , ester - water ,etc.But there are few study reports about separating non-polarity system. At present the doctor Lei Zhigang by the solvent Div^ CAN added the salt extracts rectify to separate C4 group grade in Qinghua university. There are few reports about separating the non-polarity system. The solvent with DMF and KSCN separats benzene low n-heptane from benzene in the text. It explores a new kind separation method of the low n-heptane of the benzene,and widens the vision of the separation of the extract rectification.Through the balancing experiment of vapour liquid,we see about the type of the salt,density,temperature,solvent ratio,etc. Through the experiment of the extract rectify with salt,we investigate these factors affect the content of n-heptane in cauldron liquid.The results showed that when dropping the extraction agent continuously, V(extraction solvent):V(raw material) is 1.2, percent of quality of KSCN is 12%, the n-heptane whose percent of volume is 0.1 is separated from material liquid with extractive rectify with salt 95% of rc-heptane can obtained in the tower top ,The n-heptane in tower kettle can drop to 0.8%.On the basis of experiment,we go on the comments of DMF extract rectify with salt separating n-heptane-benzene of the no-polarity system in theory in this text.And on the basis of the balanced model of liquid phase of air,Pan XiaoMei of university of Tianjin putting forward,which apply to .the no-polarity things.更多还原