【作者】 邬茂；

【导师】 袁华；

【作者基本信息】 武汉工程大学 ， 化学工艺， 2009， 硕士

【摘要】 碳酸二苯酯(Diphenyl Carbonate, DPC)是一种重要的化工原料中间体,主要用于塑料工业制造聚碳酸酯(PC)。聚碳酸酯具有优异的电绝缘性、尺寸稳定性、耐化学腐蚀性和高抗冲击强度及透明性,广泛应用于汽车制造、电子电气、光学存储、建筑建材、航空航天、办公设备等领域,是近年来市场增长速度最快的通用工程塑料。碳酸二苯酯的合成方法主要有三种,即光气法、酯交换法和氧化羰基化法。其中,光气法环境污染严重,酯交换法的工艺路线较长,而氧化羰基化法因其流程短、环境友好成为国内外合成碳酸二苯酯的研究热点。氧化羰基化法包括均相催化和非均相催化,但均相催化存在以下缺点:(1)因卤素离子的加入而加剧设备腐蚀;(2)催化剂不能回收;(3)产品后续分离困难。因此非均相催化法是目前国内外合成DPC的主要研究方向。本文采用铈复合金属氧化物作为载体,Pd化合物作为主要活性组分来制备负载型催化剂,非均相催化氧化苯酚一步合成DPC。实验考察了载体金属离子的组成和配比、载体和催化剂的制备方法等因素对催化活性的影响,以苯酚氧化羰基化反应合成DPC的实验结果对催化活性进行了评价。通过XRD、SEM、XPS、BET等表征手段对载体和催化剂的主要晶相和物理结构进行了测试分析,在此基础上对催化氧化机理进行了探讨。同时,本工作对非均相催化氧化合成DPC反应的工艺条件及催化剂稳定性进行了考察。经过实验及测试研究,得出的主要结论以下:(1)通过载体复合金属组分的筛选,发现以Ce-Mn复合金属氧化物为载体得到的催化剂催化活性较好。(2)最佳的载体制备方法是溶胶-凝胶法。(3)载体Ce-Mn复合金属氧化物的焙烧温度以600℃为宜,相应制备的催化剂催化活性较好。(4)载体Ce与Mn金属离子的摩尔比为1: 1时,相应制备的催化剂催化活性较好,DPC收率为9.33%。(5)载体中CuO的添加量及添加方法对催化剂的性能有较大影响。直接将铜盐添加至溶胶中、添加量为9wt%(以CuO计)时,相应制得的催化剂催化活性最好,DPC收率可达10.28%。(6)采用溶胶-凝胶法制备复合金属氧化物载体,相应得到的催化剂稳定性较好。(7)反应机理探讨分析表明:铈复合金属氧化物载体对主活性组分Pd具有较好的氧化还原协同作用。(8)通过合成DPC工艺条件的研究,发现反应温度、反应压力、反应时间等因素对DPC的收率有较大影响。优化的合成工艺条件为:Pd负载量为0.5%,反应温度75℃,总压5 MPa,氧气含量7%,反应时间12h,DPC收率可达17.06%。更多还原

【Abstract】 Diphenyl carbonate (DPC) is an important chemical intermediate, mainly used for polycarbonate (PC) in plastics industry. PC has many excellent properties such as insulation, dimensional stability, anti-corrosion, high resistance to impact and transparency, thus it becomes the fastest growing general engineering plastic, which is widely used in the field of automobile manufacture, electronic and electric industry, optical storage, building materials, aerospace and office supplies.There are three methods mainly to synthesize diphenyl carbonate: phosgene method, transesterification and oxidative carbonylation. Due to the disadvantage of the pollution with phosgene method and relatively long process with transesterification methods, the oxidative carbonylation method attracted much attention because of its environmental benign and one-step synthesis features. The method of oxidative carbonylation includes two ways of homogeneous and heterogeneous catalysis. The homogeneous catalysis method has the following drawbacks: (1) the addition of halogen ions, exacerbated the corrosion of equipment, (2) catalyst can not be recycled, (3) the products are difficult to be separated. Therefore, the heterogeneous method becomes the main research direction currently.In this paper, diphenyl carbonate (DPC) was synthesized by heterogeneous catalysis of phenol in presence of the cerium complex oxides support. The molar ratio of different metal ions within support, the preparation methods of supports and catalysts, and other factors had been studied. The activity of catalyst was evaluated by the synthesis experiments of diphenyl carbonate. The phase and physical structures of supports and catalysts were characterized by XRD, SEM, XPS and BET techniques, and the catalytic mechanism was discussed on the result of testing. The reaction conditions and stability of catalyst were also investigated subsequently.From those works, the conclusions were as follows:(1) Among different assembly of metals, cerium and manganese complex oxides had better catalytic activity.(2) The appropriate preparing method of catalyst was sol-gel method.(3) The optimal calcination temperature of support was at 600℃. At this temperature, the corresponding catalyst achieved a higher activity.(4) While the molar ratio of Ce and Mn was 1:1, the catalyst had better activity with a DPC yield of 9.33%.(5) The amount and doping methods of CuO had evident influence on the activity of catalyst. When the 9wt% Cu(NO3)2·3H2O was added to the sol directly, the catalyst had better activity with a DPC yield of 10.28%.(6) The catalysts prepared by sol-gel method had better stability.(7) Its proved by the analysis of reactive mechanism that the support of cerium complex metal oxide had favorable redox synergistic effect between the metals and the active component Pd.(8) The reaction temperature, pressure and reaction time had important influence on the yield of DPC. The optimum reaction conditions were loading amount of Pd 0.5%, reaction temperature 75℃, total pressure 5 MPa(7% O2 ) and reaction time 12 h. The yield of DPC could reach 17.06%.更多还原