高比表面积超细二氧化硅粉体的制备

PREPARATION OF SiO_2 ULTRAFINE POWDER WITH HIGH SPECIFIC SURFACE AREA

以水玻璃为原料、乙酸乙酯为潜伏酸试剂 ,采用溶胶凝胶法制备出了高温润滑脂稠化剂———高比表面积超细SiO2 粉体。考察了乙酸乙酯用量和反应温度对成溶胶时间、SiO2 粉体BET比表面积及孔体积的影响 ,并用TEM、BET低温液氮吸附和IR等分析手段对SiO2 粉体颗粒进行了表征。结果表明 ,采用该方法制得的SiO2 粉体颗粒近似呈球形 ,粒径为 2 0～ 30nm ,比表面积均大于 40 0m2 /g ,最大比表面积可达 5 0 3 38m2 /g。较理想的反应条件为乙酸乙酯与水玻璃溶液中所含SiO2 的摩尔比为 0 8,反应温度为 5 0℃。

A kind of lubricating grease thickener, ultrafine silica gel powder with high specific surface area, was prepared taking water glass and ethyl acetate as a latent acid reagent. The effects of the amount of ethyl acetate added and the reacting temperature on BET specific surface area and total pore volume were studied. The silica powder with particle diameter in the range of 20～30 nm and BET specific surface area above 400 m 2/g have been obtained. The largest specific surface area is up to 503.38 m 2/g. The ideal reacting conditions are given. The molar ratio of ethyl acetate to silica is 0.8, and the reaction temperture is 50 ℃.