Copper-Silicon Structures for Selective Catalytic Formation of Silanes

本文研究了铜催化硅与氯甲烷Rochow直接合成反应的机理和中间体。这个反应可以作为理解固体催化气固反应的一个模型。当它在工业上在大型流化床反应器中运行时，它形成二甲基二氯硅烷，硅酮聚合物的前体，选择性高达90%。它对材料性质如表面组成、催化剂的形式、促进剂的浓度和杂质等非常敏感；这项工作的目的是确定哪些材料和性能可以提高活性和选择性。反应动力学是在常压下在小型反应器中测量的，该反应器连接到用于表面分析和样品处理的超高真空系统。使用单晶硅表面，可以通过扫描电子显微镜、能量色散光谱、x射线衍射、光学显微镜、俄歇光谱、化学处理和程序升温解吸来表征反应表面的平面和凹坑。测定了氧化硅层、硅晶面、锌、锡作为促进剂，铝、铁、钙作为杂质的影响。流化床反应器的平行研究将在宾夕法尼亚州塞威克利的埃肯开发中心进行。有机硅聚合物在现代技术中无处不在，广泛应用于密封剂，润滑剂，液压油，电介质和其他应用。高质量的聚合物需要一个纯单体，在这种情况下，二氯二甲基硅烷，这就是这里要解决的问题。在直接合成反应中产生的其他硅烷对单体的污染是目前的一个问题。这项工作是与埃肯公司协调的，埃肯公司是二氯二甲基硅烷的主要供应商。二氯二甲基硅烷的主要消费者道康宁公司为这项工作提供了补充支持。

9317580 Falconer This is a study of the mechanism and intermediates of the Rochow direct synthesis reaction between silicon and methyl chloride catalyzed by copper. This reaction can serve as a model for understanding the class of solid-catalyzed gas-solid reactions. When it is run industrially in large fluidized bed reactors, it forms dimethlydichlorosilane, the precursor to silicone polymers, with selectivity as high as 90% It is very sensitive to material properties such as surface composition, the form of the catalyst, concentrations of promoters, and impurities; the objective of this work is to determine which materials and properties improve activity and selectivity. Reaction kinetics are measured at atmospheric pressure in a small reactor attached to an ultrahigh vacuum system equipped for surface analysis and sample treatment. Single-crystal silicon surfaces are used so that the planar surfaces and the pits formed on reacted surfaces can be characterized at various stages by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, optical microscopy, Auger spectroscopy, chemical treatment, and temperature-programmed desorption. The effects of silicon-oxide layers, silicon crystal face, zinc and tin as promotors, and aluminum, iron, and calcium as impurities are determined. Parallel studies in a fluidized bed reactor will be conducted at the Elkem Development Center in Sewickley, PA. Silicone polymers are ubiquitous in modern technology with wide application as sealants, lubricants, hydraulic fluids, dielectrics, and other applications. High-quality polymer requires a pure monomer, in this case dichlorodimethylsilane, and it is this issue that is addressed here. The contamination of the monomer by other silanes formed as byproducts in the direct synthesis reaction is presently a problem. This effort is coordinated with Elkem Corp., a major supplier of dichlorodimethlysilane. Supplementary support for this effort is provided by Dow-Corning Corp., a major consumer of dichlorodimethlysilane.