The Study On The Synthesis And Characterization Of Modified Trisiloxane

Polyether modified silicone oil is an important organic silicon compounds, it was mainly preparaed through the hydrosilylation. Hydrosilylation is one of the most important reaction, which is used widely. Many organic silicon compounds can be synthesized with this reaction. Generally, hydrosilylation is performed in the liquid phase using a homogeneous catalyst such as Speier's catalyst. However seperation of the catalyst from the reaction mixture is troublesome. Using supported catalyst, which has both properties of homogeneous and heterogeneous catalysts for hydrosilylation, is one of the solutions for this problem. Thus, it is not surprising that efforts to improve the efficiency and broaden the range of application of the supported catalysts and the processes are ongoing.With the use of polyethylene glycol ligand, and the use of carrier such as silica, aluminum oxide, activated carbon, these catalysts display higher catalytic activity for the hydrosilylation reaction of polyether-400 with hydrogen trisiloxane. It can improve the hydrosilylation in the aspects of accelerating the reaction rate, shorten the reaction induction period, improve the final conversion rate of hydrogen trisiloxane.The effect of temperature, the quantity of catalyst, reactant ratio, and catalyst activation methods were discussed. It is showed that catalyst with the use of polyethylene glycol ligand has a higher catalytic activity than that without polyethylene glycol ligand.Optimum conditions when using Speier as catalysts are: temperature:120℃, the amount of catalyst: 0.0075%, the ratio of polyether-400 with hydrogen trisiloxane: 1.1:1.0, the conversion of hydrogen trisiloxane reached 83.79% in 5 hours.Optimum conditions when using Pt/SiO₂ as catalysts are: temperature:110℃, the amount of catalyst: 0.01%, the ratio of polyether-400 with hydrogen trisiloxane: 1.2:1.0, the conversion of hydrogen trisiloxane reached 89.54% in 10 hours.Optimum conditionswhen using Pt-PEG/SiO₂ as catalysts are: temperature:110℃, the amount of catalyst: 0.015%, the ratio of polyether-400 with hydrogen trisiloxane: 1.2:1.0, the conversion of hydrogen trisiloxane reached 93.62% in 8 hours. When using Pt/A_l2O₃ as catalysts, the optimum conditions are as follows: temperature: 120℃, the amount of catalyst: 0.01%, the ratio of polyether-400 with hydrogen trisiloxane: 1.1:1.0, the conversion of hydrogen trisiloxane reached 88.86% in 9 hours. When using Pt-PEG/A_l2O₃ as catalysts, the optimum conditions are as follows: temperature: 110℃, the amount of catalyst: 0.015%, the ratio of polyether-400 with hydrogen trisiloxane: 1.1:1.0, the conversion of hydrogen trisiloxane reached 93.22% in 9 hours. When using Pt/C as catalysts, the optimum conditions are as follows: temperature: 110℃, the amount of catalyst: 0.01%, the ratio of polyether-400 with hydrogen trisiloxane: 1.1:1.0, the conversion of hydrogen trisiloxane reached 88.67% in 6 hours.When using Pt-PEG/C as catalysts, the optimum conditions are as follows: temperature: 110℃, the amount of catalyst: 0.0125%, the ratio of polyether-400 with hydrogen trisiloxane: 1.0:1.0, the conversion of hydrogen trisiloxane reached 94.71% in 4 hours.The modified trisiloxane using polyether-200 has better defoaming performance than that using polyether-400 and polyether-600. Mass fraction of 10% of the solution can in 84 seconds down the volume of the bubble from 1000mL to 520mL, defoaming time of 99 seconds.The modified trisiloxane using polyether-200 has better wettability in the surface of the paraffin than that using polyether-400 and polyether-600. Within 21 seconds 0.03% mass fraction of the solution can change the contact angle to 16.95°.