【作者】 文飞；

【导师】 李希；

【作者基本信息】 浙江大学 ， 化学工程， 2010， 硕士

【摘要】 烷基芳烃的MC液相催化氧化过程是石油化工领域最重要的过程之一,它的主要特点是以Co/Mn/Br三元催化体系为催化剂,有机羧酸为溶剂,空气或氧气为氧化剂,通过液相催化氧化将烷基芳烃化合物氧化成为相应的醛或者羧酸类化合物。本文主要针对甲苯、异丙苯和2,6-二异丙基萘的液相催化氧化过程进行了研究。甲苯液相氧化过程以钴-锰-溴为催化剂,通过空气氧化甲苯制备苯甲醛。本文详细考查了不同溶剂、甲苯初始浓度、催化剂浓度、催化剂配比和反应温度对甲苯液相氧化的影响,并根据甲苯液相氧化反应机理建立了动力学模型,较好的拟合了实验数据。研究发现甲苯氧化速率和甲苯初始浓度遵循表观级数趋于零的动力学规律,甲苯初始浓度减小,苯甲醛的最高收率增加,达到此收率的反应时间减小;催化剂浓度增加,苯甲醛的最高收率也随之增加;催化剂配比对苯甲醛的最高收率影响不大,增加钴锰比会在一定程度上抑制甲苯各步反应速率;甲苯和苯甲醛的活化能相差不大,很难通过改变反应温度来提高苯甲醛的最高收率。由于2,6-二异丙基萘液相氧化过程非常复杂,所以本文首先选取异丙苯作为模型物,研究异丙苯液相氧化反应机理,并确定异丙苯初始浓度、催化剂浓度和反应温度对异丙基氧化的影响,在此基础上通过正交实验确定半连续过程2,6-二异丙基萘进料流量、催化剂浓度、催化剂配比和反应温度的影响,继而考查了助催化剂、金属离子添加剂和含氮化合物对于提高2,6-萘二甲酸收率的影响。结果发现几种因素对2,6-萘二甲酸收率的影响排序为:反应温度＞进料流量＞催化剂浓度＞钴锰配比,太高的反应温度会造成萘环开裂,反应温度太低则中间产物不能完全氧化,所以比较适合的反应温度为170℃。进料流量越小对提高产品收率越有利,不过在低流量下继续降低进料流量影响不大,合适的进料流量为5ml/min,催化剂浓度越高,2,6-萘二甲酸的收率越高,钴锰比对2,6-萘二甲酸的影响不大。更多还原

【Abstract】 MC method is one of the most important process in the field of petrochemical industry, in which hydrocarbons are oxidized to aldehydes and acids using organic acid as solvent in the presence of catalysts consisting of cobalt acetate,manganese acetate and bromine compound.The liquid phase catalytic oxidation of toluene,cumene and 2,6-DIPN are discussed in this paper.The effects of different solvent,initial concentration,catalyst dosage, catalyst proportion and reaction temperature on the result of oxidation of toluene were analyzed,and kinetic model were carried out.It could be seen from the result that the oxidation rate of toluene didn’t vary significantly with the change of toluene concentration, the highest yield of benzaldehyde increased with the decrease of toluene concentration and the increase of catalyst dosage;catalyst proportion had no significant influence on the yield of benzaldehyde,and the oxidation of toluene could be inhibited by increasing Co/Mn;there was no significant difference between the activation energies of toluene and benzaldehyde, and the yield of benzaldehyde could not be improved by changing reaction temperature.As the oxidation process of 2,6-DIPN are difficult,cumene were selected as the model to interpret the oxidation mechanism of isopropyl group.The effects of initial concentration, catalyst dosage and reaction temperature were discussed.Based on this result,an orthogonal experiment was carried out,and the effects of Br,metal ions additives and organic nitrogen compounds on the yield of 2,6-NDCA were discussed.The results shown that influence order for the yield of 2,6-NDCA in the orthogonal experiment were:reaction temperature＞feed flux＞catalyst dosage＞Co/Mn.High temperature could cause the cleavage of naphthalene ring, and low temperature could not give rise to the full oxidation of intermediate products,then the suitable temperature could be 170℃.It is good for producing 2,6-NDCA to decrease the feed flux and increase the catalyst dosage,however there was no significant influence of Co/Mn for the yield of 2,6-NDCA.更多还原