Naphthalene pitch is a kind of asphalt obtained from pure naphthalene or naphthalene homologue through self reaction. Naphthalene pitch has the characteristics of less heteroatom and concentrated molecular weight, which is commonly used to prepare binder asphalt and mesophase pitch with excellent performance.

①萘的分子结构及其共聚物分子结构

① Molecular structure of naphthalene and its copolymer

萘的分子结构

Molecular structure of naphthalene

从萘的价键结构模型看，萘的结构为高度均匀对称的六元环分子，其稳定性很高，在570℃以下不分解。在500℃以上，高压下，萘本身可以自身聚合，主要形成以下形式的低聚物，为萘沥青的主要成分：

According to the valence bond structure model of naphthalene, the structure of naphthalene is a highly uniform and symmetrical six membered ring molecule with high stability and does not decompose below 570 ℃. When the temperature is above 500 ℃, the main component of naphthalene is naphthalene, and the main component is naphthalene

因为自聚合反应条件比较苛刻，所以萘沥青制备方法，主要靠阳离子催化聚合，使萘沥青在较低的温度下合成，主要包括ALCL3催化和HF/BF3催化。

Because of the harsh self polymerization reaction conditions, the preparation method of naphthalene pitch mainly relies on cationic catalytic polymerization to make naphthalene pitch synthesized at lower temperature, mainly including AlCl3 catalyst and HF / BF3 catalyst.
              

①ALCL3催化法

① AlCl3 catalytic method

在ALcl3的催化作用下，在100℃左右的低温下，萘就可开始发生热缩聚反应及分子内和分子间的转变。ALCL3催化主要以阳离子聚合为主，可以生成含有环烷结构的中间体，这种结构正是易于形成流线中间相的结构。所以利用ALCL3催化聚合可以制备萘系中间相沥青。

Under the catalysis of AlCl 3, the condensation reaction and intramolecular and intermolecular transformations of naphthalene can begin at about 100 ℃. AlCl3 catalyst is mainly cationic polymerization, which can produce intermediates containing naphthenic structure, which is easy to form streamline mesophase structure. Therefore, naphthalene based mesophase pitch can be prepared by AlCl3 catalytic polymerization.

尽管在催化剂ALCL3的作用下，萘可以在较低温度下发生聚合反应，但由于ALCL3在反应过程中以熔融态形式存在，且在生成的产物中有一定的溶解度，加之所得产物萘沥青的黏度较大，使催化剂与沥青产物完全分离非常困难。而残留的少量ALCL3使沥青灰分较高，所以影响碳制品的性能。目前济宁碳素利用此方法制备中间相沥青，灰分在400ppm左右。

In addition, the product can be polymerized in the form of CL3 in the presence of the catalyst at a certain degree of temperature due to the high solubility of the product. The residual AlCl3 makes the ash content of asphalt higher, so it affects the performance of carbon products. At present, Jining carbon uses this method to prepare mesophase pitch, and the ash content is about 400 ppm.

②HF/BF3催化法

② HF / BF3 catalytic method

HF是一种质子酸，其阴离子酸根F-亲核性很强，加之F-的直径特别小，致使F-紧紧的附着在H+周围，一方面削弱H+对C=C双键的亲和力，另一方面阻止了其他基团与H+的接触，是反应相对难于进行；即使发生阳离子聚合，也易于使反应终止。HF/BF3体系，既有较强的酸性，阴离子BF4-亲核性又弱，体积也大，是制备萘沥青理想的催化剂。

HF is a kind of protonic acid, its anion acid radical f-nucleophilic is very strong, and the diameter of f-is very small, which makes f-tightly adhere to H +, on the one hand, it weakens the affinity of H + to C = C double bond, on the other hand, it prevents other groups from contacting with H +, which is relatively difficult to carry out the reaction; that is, cationic polymerization can also easily terminate the reaction. HF / BF3 system is an ideal catalyst for the preparation of naphthalene pitch because of its strong acidity, weak nucleophilicity and large volume.

经过控制合成条件，合成的萘沥青软化点不超过90℃，苯不溶物可以为0，这种沥青是制备优良碳材料的前驱体，可以直接用来做粘结剂，经过处理后，可以制备流动性好的中间相沥青。

After controlling the synthesis conditions, the softening point of the synthesized naphthalene pitch is not more than 90 ℃, and the benzene insoluble substance can be 0. This kind of pitch is the precursor of preparing excellent carbon materials, which can be directly used as binder. After treatment, mesophase pitch with good fluidity can be prepared.

以上就是萘沥青制备方法的介绍，希望对大家有所帮助，如您想要了解更多资讯内容请点击网站：精萘http://www.jnjdbc.cn。

The above is the introduction of naphthalene asphalt preparation method, hope to help you, if you want to know more about the content, please click the website: refined naphthalene http://www.jnjdbc.cn 。