Preparation method of silver-silicon catalyst, silver-silicon catalyst and application of silver-silicon catalyst

Abstract

The invention discloses a preparation method of a silver-silicon catalyst, the silver-silicon catalyst and application of the silver-silicon catalyst. According to the preparation method, mesoporous silica nano microspheres with large specific surface area, uniform pore size distribution and nanoscale center divergence short pore channels are used as carriers, a silane coupling agent is adopted tofunctionalize the amino groups on the surfaces of the mesoporous silica nano microspheres, then silver ions are connected to the functional groups of the pore channels under the action of coordination bonds, and finally the silver ions adsorbed in the pore channels are reduced into nano-silver particles in situ under the action of a reducing agent. Compared with a traditional catalyst taking silver as an active component, the catalyst prepared by the invention has the characteristics of remarkably reduced usage amount of noble metal silver, high dispersity, high activity and good stability, and shows excellent catalytic performance in preparation of methyl glycolate by hydrogenation of dimethyl oxalate, the conversion rate of dimethyl oxalate is greater than 99%, the selectivity of methylglycolate is not less than 94.9%, the yield is not less than 94.3%, and the method has a good industrial application prospect.

Description

technical field [0001] The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method of a silver-silicon catalyst, a silver-silicon catalyst and an application thereof. Background technique [0002] Methyl glycolate is an important organic chemical raw material with good biocompatibility and degradability, and is widely used in chemical, pharmaceutical, fragrance, polymer materials and other fields. The synthetic routes of existing industrialized methyl glycolate mainly include formaldehyde carbonylation method, methyl formate coupling method, chloroacetic acid esterification method using petroleum and its derivatives as raw materials, and high-efficiency catalysts are also used to syngas. Prepared by hydrogenation of dimethyl oxalate. The latter is a more economical and environmentally friendly non-petroleum-based process route due to wider sources of syngas, with significant economic benefits and broad market prospe...

AI Technical Summary

Problems solved by technology

In CN104492429A, the Ag loads used in all examples are greater than 10wt%, and under the conditions of different carriers and preparation methods, the yields of most examples are less than 90%

[0007] (1) The preparation of silver-based catalysts requires high-temperature calcination to reduce Ag, which is easy to cause the aggregation of silver particles, and the obtained Ag particles have fewer lattice defects, which is not conducive to the activation and diffusion of hydrogen (Nanoscale, 2016, 8, 5959-5967.), resulting in low catalytic activity; and the high-temperature calcination process strengthens the role of the silver precursor and the carrier, which is not conducive to the reduction of silver, so that the silver-based catalyst also contains unreduced Ag + , resulting in a reduction in the number of silver active sites on the catalyst surface (Chem.Commun., 2010, 46, 4348-4350.), resulting in low catalytic activity

[0008] (2) The silver-based catalyst with high loading also has the phenomenon of Ag particle sintering and enlargement during the reaction, which affects the stability of the catalyst (JP 06135895 and ChemComm, 2010, 46(24): 4348-4350)

[0009] (3) Traditional mesoporous materials are used as carriers, such as SBA-15, MCM-41, activated carbon, carbon nanotubes, etc. Although the limiting effect of mesoporous can effectively prevent the agglomeration and sintering of metal particles, due to its too large pores Long (micron scale), metal nanoparticles are easy to penetrate into the pores, resulting in low dispersion of Ag on the surface of the catalyst (<0.2, measured by chemical adsorption method), and low utilization of Ag, so a large loading of Ag is required, so that Ag The cost of silver-based catalysts remains high, which is not conducive to the industrial application of silver-based catalysts

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