The Aqueous Phase Synthetic Methods For Bis-(Triethoxysilylpropyl)-Tetrasulfide

In this article, based on the summation of research and development for silane coupling agents and the analysis of various synthetical techniques for bis- (triethoxysilylpropyl)tetrasulfide, the synthetical techniques for bis-(triethoxysi- lylpropyl)tetrasulfide in water were studied. Chloropropyltrichlorosilane as raw material, the middle product that had the purity of 99% was synthesized by alcoholysis, distillation, neutralization and filtration, finally the bis-(triethoxysi- lylpropyl)tetrasulfide was synthesized by using the technology of phase transfer.In the process of research into the synthetical techniques, analysis methods such as complexmetric titration, gas chromatography, GC-MS, high pressure liquid chromatography, LC-MS and infrared spectrometry were used. The result indicated that the synthesized bis-(triethoxysilylpropyl) tetrasulfide was lightly yellow and the conversion rate was 93.4%.Based on the analysis of the process conditions of chloropropyltriethoxy- silane, the reaction did not need to add the solvent, only changed the order in which first added chloropropyltrichlorosilane, then dropped ethanol. Fully considered the reaction conditions on the experiment, ensured that the reaction needed the temperature and the vacuum were increased continuously. Meanwhile, determined the mol ratio of chloropropyltrichlorosilane with ethanol was 3.2~3.2:1, reaction time was about 4.5hours.The present research was characterized by adding the butter to the aqueous phase, which minimized or stopped gelling of the bis-(triethoxysilylpropyl)- tetrasulfide, and minimized the outgrowth of H2S. Because of adding the phase transfer catalyst, made the synthesis in water be achieved and the techniques had the character of low costs, the products had high purity, good appearance and long guarantee period.