Study On The Synthesis Of Triethoxysilane By Alcholysis Process

Triethoxysilane is a kind of alkoxysilane, which can be used in the preparation of chain polysiloxane; preparation of high purity silica powder; preparation of high purity monosilane gas; preparation of silane coupling agent through hydrosilation and so on. In industry, there are two ways for the preparation of triethoxysilane, the first is direct process, which is carried out by Rochow in 1948, but is soon given up for the low conversion because of limited experimental condition then. In recent yeas, with the growing demand of triethoxysilane, many scholars in both domestic and foreign had aimed at direct method again. At present, direct process could be divided into"wet method"and"dry method", but the effect of both methods is not satisfied. The second way is alcoholysis process, also called esterification process. The principle is that alcohol-base take place of the chlorine-base to prepare triethoxysilane. This method is the most popular and mature way to prepare triethoxysilane, but there is an abuse that it will produce a lot of HCl during the process. If we can recycle the HCl, we can solve the problem, as the advance in science and technology, it is not difficult to recycle the HCl.There are a lot of differences among different companies on esterification process and there are not many reports on this. In this paper, we design three kinds of reactor including tubular reactor, tank reactor, tower reactor, and ensure the best reactor and best routing through the research on three reactors. After the preparation of triethoxysilane, there parts of HCl dissolve in the crude products so that we should add some base in. We choose solid organic base but not inorganic base, because the hydroxyl would bring in water, triethoxysilane would be hydrolyzed to polysiloxane. During the neutralization process, we don't need to control the amount of solid organic base because the base will turn into solid when we low the temperature, the neutralization process would not bring in any impurity. After the neutralization, we distill the product to separate a small quantity of impurities, and accept the final products.In this paper, we simulate the rectification device by CHEMCAD, and find the final plan, we rectify four products with two tower in series, and got the triethoxysilane of 3N purity.