正硅酸乙酯的水解、缩合过程研究

Studies on the Hydrolysis and Polycondensation Process of TEOS

本文用ＣＣ－ｇＡ气相色谱仪测定并计算了正硅酸乙酯水解与缩合形成溶胶－凝胶的转化过程中的ＲＯＨ、Ｈ２Ｏ、Ｓｉ－ＯＲ、Ｓｉ－ＯＨ的浓度变化．研究了温度、ｐＨ对水解与缩合反应的影响．得出了水解与编合反应机理与速率常数．发现酸性体系对水解有利而对缩合不利；且缩合反应主要是在硅醇之间进行．碱性体系对缩合有利而对水解不利；且缩合反应主要是在硅醇与硅酯之间进行．

The hydrolysis and polycondensation process of TEOS were studied by taking into measuring of ROH, HOR, Si-OR Si-OH with CC-9A Gas Chromatoraphy, and temperature, pH. The mechanism and reaction rate constants of hydrolysis and condensation on TEOS were first deduced. It was found that: 1)The hydrolyzing rate is quickened with acid as catalyst, but polycondensation rate slows down and polycondensation reaction is Si-OH+HO-S-St-O-St+H2O. 2) Polycondensation rate is quickened, hydrolying rate slows down with base as catalyst and polycondensation reaction is: St-OR+HO-Si-St-O-Si+ROH.