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铜基纳米催化剂的制备及在Rochow反应中的催化性能研究
李晶
学位类型博士
导师苏发兵
2017-07
学位授予单位中国科学院研究生院
学位授予地点北京
学位专业材料学
关键词Rochow反应 M2 选择性 铜基纳米催化剂 协同作用
摘要

甲基氯硅烷是最重要也是用量最大的有机硅单体,是整个有机硅工业的基础和支柱。工业生产中,其主要是采用直接法(即Rochow反应)来合成。采用固态的硅粉(Si)在铜基催化作用下与气态的一氯甲烷(MeCl)接触反应,目标产物为二甲基二氯硅烷(M2,Me2SiCl2)。铜基催化剂是该反应的经典催化剂,然而,目前的研究主要集中于微米尺度铜催化剂的开发,且催化性能即M2选择性和Si转化率仍然有待进一步提高。因此,开发新型高效催化体系及探索其催化机理仍然是一项具有理论和实际应用价值的研究课题。基于此,本论文开展了以下研究工作:(1) 在采用液相还原法制备金属Cu纳米线基础上,通过调控温度和时间氧化制备了一系列含有不同Cu、Cu2O和CuO组分的纳米线和纳米管材料,并将其用于Rochow反应中。相较于一元和二元组分催化剂,三元Cu-Cu2O-CuO多壁核壳纳米线表现出更加优异的M2选择性和Si转化率。这归因于三元层状异质结构及不同组元间的协同作用。(2) 采用六面体、八面体和菱形十二面体三种Cu2O纳米晶作为模型催化体系研究了晶面对Rochow反应催化性能的影响。实验结果表明暴露{100}晶面的Cu2O六面体M2的催化选择性最优,这归因于其表面富氧原子的配位结构。在此基础上将ZnO纳米粒子负载在不同晶面的Cu2O纳米晶上得到Cu2O/ZnO异质结纳米晶,催化性能显示负载于六面体Cu2O的异质结纳米晶表现出更加优异的M2选择性和Si转化率,证实其形成的P-N异质结构对催化性能具有促进作用。(3) 采用硬模板法制备了蜂窝状CuO/ZnO纳米复合物,并将其回用于Rochow反应中。本方法是以回收的有机硅单体合成反应中的废触体为原料。质量占比67wt%的炭黑制备的CZ80/20复合物与商业催化剂的催化性能基本相当,这得益于二元组分比例及二者的协同作用。本方法对循环工艺的发展进行了有益的探索。

其他摘要

Methlylchlorosilane is the most important and the largest amount of the organosilicone monomers, which is the foundation and pillar of the entire organosilicon industry. In industrial production, it is mainly synthesized by the direct method (ie Rochow reaction). Silicon powder (Si) directly reacts with gaseous methyl chloride (MeCl) in the presence of copper-based catalyst, and the target product was dimethyldichlorosilane (M2, Me2SiCl2). The copper-based catalyst is the classic catalyst for this reaction. However, the current research mainly focused on the development of micron-scale copper-based catalysts, and the catalytic properties (M2 selectivity and Si conversion) still need to be further improved. Therefore, to develop new and efficient catalytic system and explore its catalytic mechanism is still a research topic with theoretical and practical value. Based on this, the following research work is carried out in this paper:(1) A series of copper-based catalysts with core-shell or tubular structure containing varius contents of Cu, Cu2O, CuO were prepared by adjusting temperature and time oxidation on the basis of the metal Cu nanowires prepared by liquid phase reduction method, and were used in Rochow reaction. The ternary Cu-Cu2O-CuO core-shell nanowires exhibited more excellent M2 selectivity and the Si conversion than single and binary component catalysts, which is due to the synergistic effect among the ternary layered heterostructures and the different components.(2) The crystal facet effect on the catalytic performance of Rochow reaction were studied by using hexahedral, octahedral and rhombic dodecahedral Cu2O nanocrystals as model catalysts. The experimental results show that M2 selectivity of hexahedral Cu2O with {100} factet is the best, which is attributed to the coordination structure of oxygen-rich atoms on the surface. On the basis of this, ZnO nanoparticles were supported on Cu2O nanocrystals with different crystal planes to obtain Cu2O / ZnO heterojunction nanocrystals. The catalytic performance showed that the that Cu2O / ZnO nanocrystals prepared by hexahedral Cu2O showed more excellent M2 selectivity and Si conversion, and confirmed that the formation of P-N heterostructures promoted the catalytic performance.(3) The honeycomb-like CuO / ZnO nano-hybrids was prepared by hard-plate method and were used in the Rochow reaction. The method is based on the recyclable waste contact mass in the organosilicon monomer as raw material. The catalytic performance of CZ80 / 20 with 67% CB was equivalent to of the commercial catalyst. This also benefited from the synergistic effect of binary nano-hybrids. This method has been helpful for the development of the recycling process. 

语种中文
文献类型学位论文
条目标识符http://ir.ipe.ac.cn/handle/122111/24230
专题研究所(批量导入)
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李晶. 铜基纳米催化剂的制备及在Rochow反应中的催化性能研究[D]. 北京. 中国科学院研究生院,2017.
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