草酸二乙酯气相加氢制乙二醇催化剂分析-化学工艺专业毕业论文.docx

捅要
由一氧化碳出发,偶联得到草酸二酯,然后经草酸二酯催化加氢制乙二醇的路线,能够避免传统方法对环境的污染,充分利用各种CO资源,节省燃料和能源,是公认的技术性和经济性较好的一种绿色化工路线。本文对草酸二乙酯催化加氢制乙二醇反应体系的催化剂进行了研究。
草酸二乙酯加氢制乙二醇的反应分为两步:草酸二乙酯首先加氢生成乙醇酸乙酯,生成的乙醇酸乙酯再加氢生成乙二醇。系统热力学分析表明,草酸二乙酯加氢制乙二醇的两步反应都是可逆放热反应,其中,低温对生成乙醇酸乙酯的反应有利,而高温对生成乙二醇的反应有利。同时,升高温度对产生副产物乙醇和乙二醇单乙醚有利。因此适宜的反应温度对增加产物和减少副产物有利。实验结果与热力学分析结果一致。
通过对催化剂的制备中各组分来源的选择,制备方法、加料方式、活性组分含量的考察得到:以硝酸铜为铜源、以酸性硅溶胶为载体、用共沉淀并流加料方式制备的、含活性组分25%(、砷的Cu/Si02催化剂,经350℃还原活化后,使此反应具有较高的转化率和乙二醇收率。通过对草酸二乙酯加氢工艺条件的考察得到,反应温度为240"(3,反应压力为1MPa,氢酯比为200的条件下,加氢反应获得较高的DEO转化率和EG收率。
运用XRD、ESEM、TPR、物理吸附、场发射透射电子显微镜等表征手段对催化剂的形态、活性组分的组成及含量对反应的影响进行了深入的探讨,发现催化剂活性组分的高分散度和细颗粒有利于提高反应活性。且草酸二乙酯催化加氢制乙二醇是由Cu20和Cuo共同起作用的结果,饥20和Cuo的适宜比例是此催化加氢反应具有高转化率和选择性的必要条件。
关键词: 草酸二乙酯,乙二醇,催化加氢,催化剂
AB STRACT
Synthesis of diethyl oxalate(DEO)via catalytic coupling reaction from CO, then catalytic hydrogenation of DEO to ethylene glycol(EG)is a green chemical is a good process in technology and economic for avoiding environment pollution and making best of catalysis used in the hydrogenation of DEO to EG has been studied in this paper.
Catalytic hydrogenation of DEO to EG is a two—step first step is hydrogenation of diethyl oxalate to ethyl the second step is hydrogenation of ethyl hydroxyacetate to ethylene analysis of the reaction system indicates that the reactions of the two are reversible exothermic temperature is good for the first reaction and higher temperature is good for the second the same time,high temperature Call produce more side
,appropriate temperature is needed to get high yield of target products result of analysis also indicates that experiments prove the results of thermodynamic analysis.
Through the investigation of catalyst preparation methods,reagent adding
methods,carriers and content of ponent,it was found that the catalyst prepared by cupric nitrate and acidic silica sol and prepared by homogeneous precipitation and co-curre