Phosgene → Bis(3-isocyanatopropyl)tetramethyldisiloxane

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Twenty parts of bis(3-aminopropyl)tetramethyldisiloxane obtained in Example 1, (1) was dissolved in 400 parts of butyl acetate. Thirty parts of butyl acetate was put in a flask equipped with a stirrer, a dropping funnel, a reflux condenser, a thermometer and a phosgene introducing tube, and cooled to 10° C. with an ice bath. Phosgene passed through the flask, and the polyamine solution prepared as above was added dropwise from the dropping funnel over the course of 30 minutes. After the addition, phosgene was further passed through the flask for 30 minutes to continue the reaction between the polyamine and phosgene. The ice bath was then replaced by an oil bath, and the reaction mixture was heated to 110° C. The reaction was continued by passing phosgene for 1 hour. After the reaction, dry nitrogen was passed through the flask at 110° C. to remove dissolved gases. The unreacted materials and the solvent were evaporated off, and the residue was distilled under reduced pressure to give 4 parts of bis(3-isocyanatopropyl)tetramethyldisiloxane of the following formula having a boiling point of 131° C. at 2 mmHg. ##STR41##

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