大颗粒超高纯度硅溶胶的制备及其表征(英文)

Preparation and Characterization of Large-Particle Pure Silica Sol

采用新工艺路线制备四乙氧基硅烷(tetraethoxysilane,TEOS),以TEOS为原料制备超纯度大颗粒硅溶胶。TEOS是烷氧基硅烷法制备甲硅烷的副产物,经过精馏提纯以后,加入盐酸或氨水催化剂,采用溶胶-凝胶法制备硅溶胶。结果表明:TEOS和硅溶胶金属杂质离子总含量都低于0.3mg/L。用盐酸催化TEOS水解制备溶胶,胶粒直径达到129nm;用氨水催化,胶粒直径达272nm。当物质的量比n(C2H5OH)/n(TEOS)=6,n(H2O)/n(TEOS)=5,搅拌速度为250 r/min,制备的硅溶胶胶粒均匀度最好。加水不搅拌,胶粒很容易发生团聚,但是,当搅拌速率高于500 r/min时,胶粒出现团聚现象。

A novel approach to prepare a bulk pure silica sol was investigated.The silica sol was prepared from the hydrolysis of tet-raethoxysilane（TEOS）,which was obtained by the disproportionation,with hydrochloric acid or ammonia water as a catalyst and ethanol as a cosolvent.The results show that the total metal impurity contents in the rectified TEOS and the silica sol prepared are 0.3 mg/L.The particle size of silica sol was 272 nm when catalyzed with hydrochloric acid,and 129 nm when catalyzed with ammo-nia water.The optimum reaction conditions were an alcohol-to-TEOS mole ratio of 6,a water-to-TEOS mole ratio of 5,and a stirring speed of 250 r/min.The particles of silica sol became re-aggregation when water was added without stirring.Also,the re-aggregation of the particles occurred at 500 r/min.