Preparation Of Cu-Based Nanocatalyst And Its Catalytic Performance In Rochow Reaction

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?MeC1?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 the surface structure can attribute to the dissociation adsorption of MeCl.On the basis of this,ZnO nanoparticles were supported on Cu₂O nanocrystals with different crystal planes to obtain 5%ZnO/Cu₂O heterojunction nanocrystals.The catalytic performance showed that the that 5%ZnO/Cu₂O 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 porous 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.