【作者】 王莉；

【导师】 王艳辉；

【作者基本信息】 北京化工大学 ， 制药工程， 2009， 硕士

【摘要】 对二甲苯是合成用于制备聚脂的对苯二甲酸和对苯二甲酸二甲酯的重要中间体,此外,对二甲苯在医药、香料、油墨、农药、染料以及溶剂等领域也有着极其广泛的用途。甲苯甲醇烷基化制备对二甲苯是一条增产对二甲苯的新的工艺路线,其反应物甲醇中的一部分可通过自身转化反应生成低碳烯烃,从而在一个体系中获得两种目标产物,因此,该体系有一定的研究价值,热力学计算结果对实验和工业化生产有一定的指导作用。甲苯甲醇烷基化合成对二甲苯是一个多反应平衡同时存在的体系,各反应相互交错组成一个复杂的反应网络,为了更好的分析这些反应的热力学平衡态以及这些反应对甲苯甲醇烷基化制对二甲苯的影响,本文将甲苯甲醇烷基化反应过程中的反应按照反应物类型分为四个反应体系:甲苯自身转化体系,甲醇自身转化体系,甲苯-甲醇烷基化反应体系,甲苯和低碳烯烃烷基化反应体系。通过计算得到温度对反应平衡常数的影响,并用Matlab语言计算得到温度和压力对甲苯转化率和产物平衡组成的影响。计算结果表明,甲苯甲醇苯环烷基化反应、甲苯和甲醇积碳反应以及甲醇自身转化生成低碳烯烃的反应在热力学上均能自发进行,是正向不可逆反应;甲苯歧化反应为可逆反应,甲苯和低碳烯烃烷基化反应高温时(温度高于800K)为可逆反应;在热力学上甲苯甲醇烷基化反应更趋向于形成高级烷基化产物,甲醇向低碳烯烃的转化趋势为丁烯＞丙烯＞乙烯;目标产物对二甲苯的含量在二甲苯的平衡组成中占24%左右,受温度和压力的影响变化不大,而低碳烯烃的平衡组成随温度和压力的变化而变化。更多还原

【Abstract】 para-Xylene is a key intermediate in the synthesis of terephthalic acid and terephthalates, which are used to make polyesters. Furthermore, it is also widely used in other areas such as pharmaceutics, perfume, ink, pesticide, dye and solvent. Alkylation of toluene with methanol is a novel route to fabricate para-xylenc. Since the fact that some part of methanol can transform to lower alkenes through their own reaction, therefore making two kinds of target product obtained from one single system, this system has much potential value and its thermodynamic calculation will play an important role in instructing experiment and industrial production.The alkylation of toluene with methanol to para-xylene is a complex reaction network in which many reaction equilibriums coexist and interlock with each other. In order to analyze the thermodynamic equilibrium states of these reactions and their effects on the alkylation of toluene with methanol to para-xylene, these reaction processes were divided into four reaction systems according to reactants types in this paper: toluene transformation system, methanol transformation system, alkylation system of toluene with methanol, alkylation system of toluene with lower alkenes. In this paper, The effect of reaction temperature on equilibrium constants was calculated, and the effect of reaction temperature and pressure on the conversion rate of toluene and the equilibrium composition were also calculated through Matlab language.The results show that phenyl ring’s alkylation reaction of toluene with methanol, carbon deposition reaction of toluene and methanol as well as methanol conversion to lower alkenes can both perform spontaneously and is irreversible in forward direcation; toluene disproportionation is reversible reaction as well as alkylation reaction of toluene with lower alkenes when reaction temperature is above 800K; alkylation reaction of toluene with methanol tends to produce higher alkylate thermodynamically, reaction trend of methanol conversion to lower alkenes is butylene> propylene>ethylene;content ration of target product para-xylene is about 24% and altered little with temperature and pressure in equilibrium composition of xylene, While equilibrium composition of lower alkenes changes with temperature and pressure.更多还原