通过研究正硅酸乙酯(TEOS)水解的反应动力学, 推导出Stober法制备二氧化硅溶胶体系中反应时间与TEOS转化率关系的动力学公式。分析确定了合适的转化率, 进而用于计算二氧化硅溶胶的理论最佳反应时间。同时, 以正硅酸乙酯为硅源, 采用溶胶凝胶法在氨水催化作用下制备了不同配比的二氧化硅溶胶, 考察了氨和水的浓度对反应时间的影响, 结果表明, 两者浓度增大可以有效减少反应时间。通过成膜性检测确定制备过程中的最佳反应时间, 并与理论计算得到的最佳反应时间进行比较, 结果表明, 两者一致, 误差控制在5%以内, 说明该动力学公式具有很好的适用性。

A new formula was proposed to investigate the relationship between reaction time and tetraethylorthosilicate (TEOS) conversion rate for preparation of silica sol with Stober method, by studying the reaction kinetics of TEOS hydrolytic process. An appropriate conversion rate was then determined and used to calculate the theoretical optimal reaction time. Meanwhile, silica sols were prepared by sol-gel process using TEOS as precursor and ammonia as catalyst. It was found that the reaction time decreases with an increasing amount of ammonia and water. The values of experimental optimal reaction time were obtained, and agree with the theoretical results (the errors are within 5%), which shows good applicability of our formula.