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A kind of preparation method of tetramethyldihydrodiphenyltrisiloxane
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A technology of tetramethyldihydrogendiphenyltrisiloxane and tetramethyldihydrogendisiloxane is applied in the field of synthesizing organosilicon compounds, and can solve the problems of low yield, difficulty in scale and the like, and achieves high yield effect
Active Publication Date: 2019-08-27
GUANGDONG INST OF RARE METALS
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[0009] Usually, diphenyldichlorosilane, tetramethyldihydrogendisiloxane, and water are used as raw materials to undergo hydrolysis and condensation under the action of a catalyst to generate phenyl hydrogen-containing polysiloxane mixtures with different degrees of polymerization. Contains 2~4% tetramethyldihydrodiphenyltrisiloxane with a single degree of polymerization, and the yield is low
In the above aqueous reaction system, the hydrolysis rate of diphenyldichlorosilane and the end-capping rate of tetramethyldihydrodisiloxane have a large difference, and diphenyldichlorosilane itself will inevitably occur. Hydrolysis and condensation reaction, but it is difficult to form a large amount of tetramethyldihydrodiphenyltrisiloxane with a single degree of polymerization with the end-capping agent, so in order to obtain a large amount of tetramethyldihydrodiphenyltrisiloxane alkanes, the use of aqueous phase hydrolysis and high-temperature distillation is difficult to scale
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Embodiment 1
[0024] Add 200g of diphenyldimethoxysilane to a 2L four-neck flask equipped with a thermometer, a constant pressure dropping funnel, a stirrer, and a condenser tube, then add 10g of concentrated sulfuric acid with a mass concentration of 98%, stir for 10min and mix well; Slowly add 160g of tetramethyldihydrodisiloxane dropwise into the constant pressure dropping funnel for 2 hours. After the dropwise addition, continue to stir for 12 hours, add 20g of sodium carbonate for neutralization for 1 hour, vacuum filter, and distill the filtrate under reduced pressure. Cut off the fraction at 130~131℃ / 2.5mmHg to obtain a colorless transparent liquid, which is tetramethyldihydrodiphenyltrisiloxane. Weighing 234g, the yield is 86.03%, and the chromatographic detection content is 99.4%.
Embodiment 2
[0026] Add 200g of diphenyldimethoxysilane to a 2L four-neck flask equipped with a thermometer, a constant pressure dropping funnel, a stirrer, and a condenser tube, then add 20g of concentrated sulfuric acid with a mass concentration of 98%, stir for 10min and mix well; Slowly add 400g of tetramethyldihydrodisiloxane to the constant pressure dropping funnel for 4 hours. After the dropwise addition, continue to stir for 24 hours, add 80g of sodium carbonate for neutralization for 2 hours, vacuum filter, and distill the filtrate under reduced pressure. Cut off the fraction at 130~131℃ / 2.5mmHg to obtain a colorless transparent liquid, which is tetramethyldihydrodiphenyltrisiloxane. Weighing 242g, the yield is 88.97%, and the chromatographic detection content is 99.5%.
Embodiment 3
[0028] Add 200g of diphenyldimethoxysilane to a 2L four-neck flask equipped with a thermometer, a constant pressure dropping funnel, a stirrer, and a condenser tube, then add 15g of concentrated sulfuric acid with a mass concentration of 98%, stir for 10min and mix well; Slowly add 300g of tetramethyldihydrodisiloxane dropwise into the constant pressure dropping funnel for 3 hours, continue to stir for 15 hours after the dropwise addition, add 50g of sodium bicarbonate for neutralization for 1 hour, vacuum filter, and distill the filtrate under reduced pressure , Intercept the distillate at 130~131℃ / 2.5mmHg to obtain a colorless transparent liquid, which is tetramethyldihydrodiphenyltrisiloxane. Weighing 238g, the yield is 87.5%, and the chromatographic detection content is 99.4%.
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Abstract
Belonging to the technical field of synthesis of organosilicon compounds, the invention discloses a preparation method of tetramethyldihydrodiphenyltrisiloxane. The method consists of the steps of: adding tetramethyldihydrodisiloxane dropwise into a mixed solution of diphenyldimethoxysilane and concentrated sulfuric acid for 2-4h under room temperature stirring, then further performing stirring for 12-24h, adding a neutralizing agent, conducting stirring for 1-2h, carrying out vacuum pumping filtration, performing reduced pressure rectification on the filtrate, and intercepting 130-131DEG C / 2.5mmHg fraction, thus obtaining the tetramethyldihydrodiphenyltrisiloxane. The method provided by the invention adopts an anhydrous system for reaction, avoids the circumstance that diphenyldimethoxysilane easily undergoes hydrolytic condensation by itself in a water system to generate a polymer. The preparation method of tetramethyldihydrodiphenyltrisiloxane provided by the invention has the advantages of simple process, stable quality and high yield.
Description
technical field [0001] The invention belongs to the technical field of synthesizing organosilicon compounds, and in particular relates to a preparation method of tetramethyldihydrodiphenyltrisiloxane. Background technique [0002] Tetramethyldihydrodiphenyltrisiloxane belongs to the category of hydrogen-containing silicone oil. It is a hydrogen-containing silicone oil with a special structure and has the smallest degree of polymerization, that is, the degree of polymerization is 1. It also has the properties of hydrogen-containing silicone oil, that is, it can be used as a crosslinking agent and polymer modification intermediate for silicone rubber preparation. [0003] Described tetramethyldihydrodiphenyl trisiloxane structural formula is as follows: [0004] [0005] Appearance is colorless and transparent liquid, refractive index (25°C): 1.500, boiling point: 130~131°C / 2.5mmHg. [0006] Tetramethyldihydrodiphenyltrisiloxane is an important organosilicon intermediate,...
Claims
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