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1、太原理工大学 硕士学位论文 液相还原法制备无氯铜基催化剂及其催化氧化羰基化 姓名：王丽 申请学位级别：硕士 专业：物理化学 指导教师：谢克昌;李忠 20100601 太原理工大学硕士研究生学位论文 I 液相还原法制备无氯铜基催化剂及其催化氧化羰基化 摘 要 碳酸二甲酯(DMC)是一种用途广泛的绿色化学品 因其毒性小 工业应用 广泛而备受关注被誉为有机合成的“新基块”具有广阔的应用前景气相法 甲醇氧化羰基化合成 DMC 是热力学十分有利的化学反应 该工艺由于流程简 单环境友好成本低而引起人们的极大关注目前主要研究的催化剂多选用 金属氯化物作为前驱物催化剂中 Cl-的残留问题难以避免而研究表明由于
2、 Cl-的流失使催化剂失活设备腐蚀等问题因此无氯催化剂的制备成为重 要的研究方向King 制备出无氯催化剂 Cu2O/LZ-20M(HAR).与 CuCl/LZ-20M 有相同的初始活性Drake 等制备出无氯 Cu/SiO2催化剂其催化活性高于 Cu(NO3)2浸渍法制备的催化剂因此可以证明氯的存在对合成 DMC 非必需 Richter 等以 Y 型分子筛浸渍 Cu(NO3)2或 Cu(CH3COO)2为前躯体浸渍溶液后 加热处理然后加热处理促使分散在分子筛表面的 CuO 发生从 Cu 到 Cu 的 自还原获得无氯 Cu /Y 分子筛 本课题组曾经选用 CuCl 和 CuCl2与分子筛材料混
3、合焙烧进行固体离子交 换的方法制得 Cu/分子筛催化剂并对其进行水处理制备得到负载型 Cu2(OH)3Cl 的催化剂缓减 Cl-的残留问题最终通过热解醋酸铜得到的完全无 氯 Cu2O/AC 催化剂1具有较好的氧化羰基化性能本文以制备完全无氯的负 载型铜基催化剂为目标 采用无氯的铜盐前躯体 通过在液相中添加还原剂改 太原理工大学硕士研究生学位论文 I I 变铜的价态制备负载型铜基催化剂在 MeOH/CO/O2 =5/11/1SV=6625h-1的 条件下用其催化甲醇直接气相氧化羰基化合成碳酸二甲酯(DMC)通过 XRDSEM 等表征以及活性评价考察了还原剂铜盐前驱体沉淀剂铜负 载量载体以及载体改
4、性等制备工艺对催化剂结构和性能的影响并利用 XRDTPRBETIR 和 SEM 等表征手段对催化剂的催化性能结构和表 面性质等进行了研究得出以下主要结论 (1)通过液相还原法制备 Cu2O/AC 催化剂考察了制备条件载体氧化 亚铜负载量等因素对催化剂性能的影响结果表明常规条件下活性炭为载 体氧化亚铜负载量为 17.3%时催化剂的活性较好 (2)还原剂是影响催化剂活性物种的主要因素葡萄糖做还原剂时得到球 形颗粒 Cu2O加入量为 4g 时Cu2O 粒径最小沉淀剂催化剂的制备过程中 仅起到提供碱性环境的作用 不影响催化剂的结构和性能铜盐前躯体对催化 性能影响较大 醋酸铜为前躯体活性较好 催化剂前
5、9 小时平均时空收率最高 达到了 71.96 mg?g -1 ?h - 1 催化剂参加反应前后 活性物种组分未发生改变 Cu2O 粒径发生长大是催化剂失活的原因 (3)双氧水改性活性炭使得其表面的 C=O 键的数量增加 H2还原耗氢量显 著增加 用此载体液相还原法制备了 Cu2O/AC 催化剂 可以促进 Cu2O 和活性 炭之间的结合使得 Cu2O 在 AC 表面结合的更加紧密催化剂的活性得到改 善 关键词无氯液相还原法氧化羰基化碳酸二甲酯氧化亚铜 太原理工大学硕士研究生学位论文 I I I CHLORIDE-FREE COPPER CATALYST PREPARED BY LIQUID-PH
6、ASE REDUCTION METHOD AND OXYCARBONYLATION CATALYSIS ABSTRACT Dimethyl carbonate (DMC) is an environment benign green-chemical which regarded as “new elementary-block” has wide application prospects because of its low toxicity and extensive dustry application. Among all methods, vapour phase carbonyl
7、ation route is beneficial in thermodynamics therefor be focus as its simple process, environmental beingn a nd low cost. Metal choloride are selected as the precursor of these catalysts in presently study, thus the problems caused by chlorin lose of catalyst are mostly unavoidable, the research show
8、s that the quick deactivation results in short longevity and HCl produced bring in heavy corrosion on equipments during the DMC synthesis process due to losing Cl from the catalyst. Therefore,the chloride-free catalyst become the important research direction. King prepared chloride-free catalyst Cu2
9、O/LZ-20M(HAR) reach the high activity of CuCl/LZ-20M. Drake prepared chloride-free Cu/SiO2 catalysts with superior catalytic activity than the Cu(NO3)2 catalyst prepared by immersion method, these results show that Cl is unnecessary for DMC synthesis. Richter prepared chloride-free Cu /Y zeolites ca
10、talysts, which were used Y zeolite impregated in the solution of Cu(NO3)2 or Cu(CH3COO)2, then heat-treated promote reduction of CuO dispersed on the surface of zeolite Cu2+ to Cu+. Our team once prepared the Cu/zeolite catalyst via SSIE(solid state ion exchange) by heating the mixed sample of CuCl
11、or CuCl2 with zeolites, and prepared supporting Cu2(OH)3Cl catalyst by aqueous treatment to relief the 太原理工大学硕士研究生学位论文 I V problems caused by chlorine lose. And finally, the Cu2O/AC catalysts has good oxycarbonylation performance which prepared by pyrolysis of copper acetate dispersing in the surfac
12、e of supports. This thesis is aimed at prepare chloride-free catalyst and changing the copper valent by adding reducing agent in liquid phase. the catalytic activities of Cu2O supported were studied on oxidative carbonylation of methanol to dimethyl carbonate, the effects of reducing agent, copper s
13、alt precurs, copper contents, precipitator, support and support modification were investigated. Also XRD, TPR, IR and SEM chacterization means were used to study these catalysts. After comparing the results of evaluation and characterization, the conclusions were listed as follow: (1) Prepared Cu2O/
14、AC catalyst by liquid-phase reduction method.The effect of preparation condition, support and Cu2O laoding amount were investigated. The result: Under the normal condition, active carbon as support, catalyst show best performance when Cu2O laoding amount was 17.3%. (2)Reducing agent is the main fact
15、or which effect active species when glucose as reducing agent and dosage is 4g, Cu2O particle was global and its size small; precipitator doesnt change catalyst structure and performance, only provide alkaline condition; Copper salt precursor had greatly influence on catalyst performance, copper ace
16、tate is the best of we tested. The average STY of first 9 hours was to 71.96 mg?g - 1 ?h - 1. The reason of catalyst deactivation is not active species but for Cu2O particle dimeter grow up. (3)Hydrogen peroxide modified active carbone make the quantities of C=O bond increased, so hydrogen consumption increase obviously. This change can promote combine between Cu2O and support result in activity improvement. KEYWORD: chloride-free, liquid-phase reduction method, oxycarbonylation, dimethyl ca
