【作者】 丁浩；

【导师】 王广建；

【作者基本信息】 青岛科技大学 ， 化学工程， 2009， 硕士

【摘要】 活性炭作为催化剂载体,除了具有价格低廉、性质稳定、孔隙结构发达、比表面积大、吸附性能强等一系列特点之外,还有一个突出的特点就是活性炭材料能够通过物理或化学手段改变其表面的物理和化学性质,具有极强的町塑性。对活性炭载体进行预处理的作用,除了在一定程度上改变了活性炭的比表面和孔结构等物理性质之外,最大的作用是在活性炭表面引入了有利于把前驱体吸附的功能性离子或基团。活性炭预处理,是在活性炭表面引入了各种类型的酸性基团:而对于湿法非氧化性预处理,是在活性炭表面引入了处理剂自身的部分离予或基团。这些功能性离子或基团与贵金属离子的相互作用直接受功能性离子或基团的种类和浓度的影响,最终决定了金属钯在活性炭表面的分散状态。因此,对预处理试剂和预处理条件进行适当的调控,可以在活性炭表面引入合适的功能性离子或基团,从而制备高分散的活性炭负载钯催化剂。本文对Pd/C催化剂,活性炭载体进行了表征,比如比表面积和孔容。并在此基础上对表征数据进行了讨论。通过对催化剂进行扫描电子显微镜微和能谱（SEM和EDS）等方法联用分析,发现用氧化负载法能够更好的使催化剂的活性组分均匀的分伽在载体上,有利于提高催化剂的活性。一定浓度的硝酸为介质,采用超声波处理活性炭载体时,超声空化作作用会导致活性炭中孔孔容增加,载体pH值降低,灰分降低,有利于Pd/C催化剂活性的提高。通过采用H₂O₂、盐酸、硝酸和超声波处理等手段对活性炭载体进行前处理,最佳制备工艺为PdCl₂的浓度O.5wt%;浸渍时间为8 h:甲醛用量是1.5 mL;浸渍pH值为7.5。做了不同时间下的超声处理,其中10 min超声处理的活性碳作为载体制备的Pd/C催化剂,显示了最高的催化活性,适当的超声作用,可以大大减少活性炭表面与其内部的灰分含量,减少表面不稳定的含氧基团,并保持活性炭中孔结构不变,从而有利于Pd的负载和分散,从而提高钯炭催化剂的活性。制得催化剂样品的比表面积、孔容分别为1356.75 m²/g和0.7068 mI//g。本论文还系统研究了在265℃～285℃、l～7MPa左右的反应压力下的（Pd/C,）(Pd含量为O.5%（质量百分比）催化剂用于对苯二甲酸加氢精制反应的速率常数规律。假定该反应为拟一级反应,在该反应温度下建立了反应速率方程,证明了在265～285℃时对苯二甲加氢,该反应对该反应为一级反应,反应速率常数k与T的关系符合k=A×exp（.E/RT）方程式的反应温度下的反应规律,与实验数掘比较表明已经得到的宏观动力学方程的估算是准确的。研究了在100～170℃温度下、l～5MPa反应压力和不同催化剂用量下2,5-二甲氧基.4.氯苯胺精馏残渣加氢脱氯反应规律,并推导了可能的反应速率常数。确定了最佳的反应条件为:催化剂用量为0.65%/0（以原料重量为标准）,转速500r/min,反应温度l 50℃,反应时间5h;2,5-二-甲氧基-4-氯苯胺精馏残渣反应足以其原料进行加氢脱氯实验,得出其促进反应的方程为k=27.97×exp（-28.789×10³/RT）为本论文的创新性研究。更多还原

【Abstract】 ?? Activated carbons have some advantages as catalyst supports. They are relatively inexpensive, possess a high surface area, allow easy recovery of supported metal by simple combustion of the support, and show chemical inertness both in acidic and basic media. Moreover, the activated carbon has strong plasticity. It means that the properties of activated carbon can be reformed by kinds of pretreatments. The effect of pretreatment not only have influences on the physical structure of activated carbon, but also introduce the functional ions or radicals on the surface of activated carbon to enhance the interaction between the surface and Pd metal. Changing the medium and condition of pretreatment can adjust the species and concentrate of the functional ions or radicals on the surface of activated carbon.The process of production and usage of Palladium-Carbon catalyst has been investigated. It relates to the production of supported catalysts and in particular to a method for obtaining peripheral distribution of palladium on a carrier or support material. Palladium catalysts have been found to be unusually effective in various catalytic processes. It has been proved that after the preparation of the carbon with nitric acid and hydrochloric acid, the palladium impregnation on this carrier could be used several times and has more activity. The dispersion of Pd metal is determined by the species and concentrate of the functional ions or radicals. According to SBET capacity, measured soaking conditions Pd/C catalyst for the SBET surface area, Gas Chromatography catalytic reaction product composition, identified Pd/C catalyst activity. Experimental data indicate that PdCl₂ dosage, impregnating solution pH, soaking time and reductant consumption are Pd/C catalyst activity of important factors, Through the various factors discussed with the study found the activated carbon catalyst in the amount of 1.5 g, PdCl₂ the amount of 1.0 g（0.5wt%）, impregnating solution pH 7.5, maceration time of 8 hours, 0.7068 mL/g and 1356.75 m2/g.The reductant amount of 2.0 ml catalyst obtained when the sample best catalytic activity. After 10 minutes ultrasonic wave treatment, the activated carbon has more activity, for it improve the species and concentrate of the functional ions or radicals to improve Pd load on it. The Pd/C catalyst, the activated carbon are token, the specific surface area, the dispersion of the Pd metal ,the distribution of pore size and the volume of the pore and the phenomenon in the reactions above is discussed. From the SEM and EDS, it is found that the active catalyst can uniformly distribute on the support through oxidation loading process, beneficial to improve the catalytic activity.The macro-kinetics and kinetics equation of the reaction of the refused rectify of 4-chloro-2, 5-dimethoxyaniline by hydrogenation has been studied on the radius Pd/C catalyst （0.5wt%） , 60-100mesh ) and study reaction at 100¹70℃、1～5MPa and which was put into a special-made basket in a high-pressure stirred stainless batch reactor. The reaction of the internal effectiveness of catalyst was varied with the change of temperature pressure and so on, the radius of catalyst and The kinetics of disproportion reaction was observed to determine the best preparation process of Pd/C catalyst and the optimal reaction conditions of disproportion reaction of refused rectify of 4-chloro-2,5-dimethoxyaniline. The best reaction conditions are : usage of catalyst（0.65wt%） per mass of reaction raw material ,stirring 500r/min, reaction temperature is 150℃, and reaction time is 5h;and its kinetics of disproportion reaction equation is k=27.97×exp（-28.789×10³/RT）, Also, the kinetics of purification of the terephthalic acid by hydrogenation has been studied on the Pd/C catalyst .Through the research of enunciate, if the radius of the catalyst let up, the effectiveness factor increase, the rate of the hydrogenation increase together. The reaction is a first order reaction. On the basis of it, the effectiveness of the catalyst on the different temperature at 265℃,275℃,285℃was estimated and k=A×exp（-E/RT）. In this study, the preparation of Pd/C catalyst and its application in the 4-CTP was investigated systemically with the coconut charcoal as the support.更多还原