溴诱导法乙烯渣油齐聚过程控制及高品质中间相沥青调制

The present project provides a new approach to prepare high performance mesophase pitch (MP) with high purity, high fluidity and high spinnablity for high thermal-conductivity carbon fibers. The ethylene tar(ET) will be reacted with the bromine at low temperature and then debromized at the moderate temperature, inducing the structure-directing oligomerization of ET into the naphthene-containing hydrocarbons. Such product would be further converted into high performance MP at the elevated temperature by the controlled polymerization process.. The main research content are summarized as follows: the activity and control of bromine radicals and their reaction with the ET; optimizing the numbers and the location of the naphthene structure in the hydrocarbons; kinetics and thermodynamics of the oligmerzation; the effects of naphthenic structure and residual side bonds on the structure of MP; the controlled oligmerzation with the synergistic effect of hydrogen transfer reaction and thermal polymerization, and the restraining strategy of excessive polycondensation; the effecting parameter and control of formation and evolution of mesophase microspheres; the forming mechanism and eliminating method of structural defects in the MP.. The present approach will overcome the intrinsic drawbacks of the thermal radical-polymerization method the Lewis-acid or super-acid method, giving a more economical and effective method to produce high performance MP for many applications, especially for pitch based carbon fibers. The university of brominating-induced oligomerization will use for reference in other high value-added applications of heavy oils.

针对超高导热炭纤维对其前躯体中间相沥青品质的苛刻要求，本课题试图以乙烯渣油为原料，通过可控溴自由基诱导实现原料活性位定向桥接、齐聚并形成环烷结构，协同热聚合和环烷氢转移控制反应历程，制备高纯度、高流动性、高可纺性中间相沥青。. 研究溴自由基活性控制技术、溴对原料不同活性部位的攻击比例调控及侧链环烷化数量最大化技术；研究单键齐聚、环烷、残留侧链结构对反应动力学、热力学、及最终中间相结构的贡献权重和最优化原则；协同氢转移优势及热解条件，实现促进齐聚和环烷芳构化并抑制过度缩聚；揭示体系能量最低化条件下中间相小球体生成及演化过程的影响参数和控制手段；阐明中间相沥青结构中微量织构缺陷形成机制及消除方式。 . 本研究规避了目前自由基法和Lewis酸或超酸体系的固有缺陷。复杂体系下溴桥接机制普适性原则的阐明，将对石油重油高值化，突破国外对我的技术产品遏制，具有现实的科学参考价值。

中间相沥青是一类由平面盘状芳香分子以一定取向平行排列堆积形成的多环芳烃，具有较高的分子量、较窄的分子量分布、良好的高温流变特性等特点。因其具有优异的可再加工性，被认为是制备高级炭素材料优异的母体，广泛应用于众多高精尖科技领域。乙烯渣油由于具有较高的平均分子质量、较少的杂元环组分和低廉的价格，被广泛地用作制备中间相沥青的原料。. 本文采用平均分子结构法辅之以气相色谱质谱联用技术对乙烯渣油组成进行解析，建立平均分子结构模型并预测其热反应活性。结果表明乙烯渣油具有丰富的侧链基团和高的反应活性。采用减压蒸馏对原料进行组分切割，去除部分非芳轻组分，并考察了重组分组成与切割温度之间的关系。结果表明，随着切割温度的升高，重组分中迫位缩合结构含量逐渐增加，而渺位缩合结构含量逐渐降低。当切割温度分别为200oC、250oC和300oC时，迫位缩合结构和渺位缩合结构比分别为0.44、0.76和1.02。不同切割温度所得重组分炭化结果表明，HC-250中间相生成能力最为优异，以其为原料经常压400oC调制12h得到了近乎广域型织构特点的中间相沥青。以HC-250为前驱体，考察了溴引入量、脱溴聚合温度对乙烯渣油重组分热缩聚的影响，结果表明溴的引入显著提高了乙烯渣油重组分的聚合效率。引入量越大，聚合效率越高。当溴的引入量为13.35 wt.%时，经350oC热聚合6h可获得软化点264oC，残碳率75.6 wt.%的高残碳、高软化点各向同性沥青。