1-Isocyanato-3-trimethoxysilylpropane

PreparationPreparation method of 3-Isocyanatopropyltrimethoxysilane: Specifically includes the following steps: 1) Add 3-aminopropyltrimethoxysilane, dry urea, dimethyl sulfoxide, and a small amount of trimethyl orthoacetate to a reactor; 2) Heat the system to 65–95°C under stirring, and react under vacuum of -0.08–-0.09 MPa to remove ammonia for 6–10 hours until no obvious bubbles emerge from the reaction system, then stop vacuuming to obtain a mixture of ureapropylsilane and solvents; 3) Add a small amount of catalyst to the reaction system, and dilute 98% concentrated sulfuric acid with dimethyl sulfoxide at a mass ratio of 1:0.5–0.8 to obtain a mixed diluted solution. Slowly add this mixed diluted solution dropwise to the system while stirring, controlling the reaction temperature at 75–95°C and the dropwise addition time at 4–6 hours; 4) Stop adding the diluted mixture when the pH of the system drops to 6-7; then cool to below 50°C, seal and filter to remove the generated ammonium salt and other solids; obtain the filtrate, and separate the filtrate by vacuum distillation to obtain the 3-Isocyanatopropyltrimethoxysilane product.