Amorphous silicon aluminium and preparation method thereof

Abstract

The invention discloses an amorphous silicon aluminium and a preparation method thereof. In the invention, hydro-thermal treatment is carried out on amorphous silicon aluminium obtained by a carbonization method, so that the amorphous silicon aluminium has higher specific surface area and bigger pore volume, the pore distribution is more intensive, and the pore volume the pore diameter of which is 6-10nm accounts for 80-95% of the total pore volume; meanwhile, the acid distribution of the amorphous silicon aluminium is improved; the amount of moderately strong acid and L acid is improved to effectively prevent raw material modules from excessively cracking, which is favourable for improving the selectivity of a target product.

Description

technical field [0001] The invention relates to an amorphous silicon aluminum and a preparation method thereof, in particular to a method for modifying amorphous silicon aluminum prepared by a carbon dioxide neutralization method. Background technique [0002] Amorphous silica-alumina has certain pore structure and specific surface area, so it can be used as catalyst carrier and adsorbent in oil refining and petrochemical industry. Amorphous silica-alumina as a catalyst carrier requires itself to have a large specific surface and pore volume to ensure the dispersion of catalyst active components, and as a carrier for cracking catalysts, amorphous silica-alumina must also have a certain cracking activity (i.e. acidic). [0003] With the rapid development of the petrochemical industry, the demand for amorphous silicon-alumina is increasing, but the amorphous silicon-alumina prepared by the existing technology mostly uses NH 4 OH, which will produce wastewater containing ammo...

AI Technical Summary

Problems solved by technology

The preparation method is that the alkali metal aluminum salt and silicate form a mixed solution when the pH value is about 12, and then react with aluminum sulfate to prepare a silicon-aluminum carrier. The specific surface of the product is 277m 2 / g, pore volume 0.31ml / g, containing SiO 2 35wt%, the disadvantage is that the pore volume and specific surface are low, as a carrier catalyst, silica-alumina cannot provide higher metal dispersion for active components

[0006] CN1210755A discloses a kind of amorphous silicon aluminum and its preparation method, its alumina content is 10~50wt%, specific surface is 350~600m 2 / g, pore volume 0.8~1.5ml / g, infrared acidity 0.25~0.55mmol / g, its preparation process is NH 4 OH and alumina first form alumina and then decompose silicate, which will produce ammonia and nitrogen-containing wastewater and pollute the environment

In addition, the amorphous silica-alumina strong acid obtained by this method is more, which will cause excessive cracking of the catalyst, which is not conducive to the improvement of catalyst selectivity.

[0007] CN1597093A discloses an amorphous silicon-alumina prepared by carbonization method, containing 8wt%-50wt% of silicon oxide, and the specific surface is 300-550m 2 / g, the pore volume is 0.7-1.5ml / g, and the infrared acidity is 0.32-0.50mmol / g. The disadvantage is that there are many strong acids and relatively few L acids, which will cause excessive cracking of the catalyst, which is not conducive to the improvement of catalyst selectivity.

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