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US 12,753,150 B2Granted
Method for preparing isocyanate compound
AssigneeHanwha Solutions Corporation
InventorsJu Won Min, Hyun Cheol Ryu, Keedo Han
Life of this patent
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Abstract
The present invention relates to a method for preparing an isocyanate compound. According to the present invention, provided is a method for preparing an isocyanate compound that can increase energy efficiency while minimizing thermal denaturation of a reaction product and formation of by-products during the preparation of an isocyanate compound using phosgene.
Claims11
A method for preparing an isocyanate compound, comprising:
- a reaction step of reacting a salt of amine compound with phosgene in the presence of a solvent to obtain a reaction product containing an isocyanate compound, the solvent and unreacted phosgene, and
- a distillation step of distilling the reaction product in a dividing-wall distillation column, so that a stream containing the unreacted phosgene is obtained from the top of the dividing-wall distillation column, a stream containing the isocyanate compound is obtained from the bottom of the dividing-wall distillation column, and a stream containing the solvent is obtained from a side stream draw of the dividing-wall distillation column,
- wherein the distillation step is progressed so that the pressure at the top of the dividing-wall distillation column is 5 torr to 20 torr.
- wherein the distillation step is progressed so that the temperature at the bottom of the dividing-wall distillation column is 165° C. or less and the temperature of a reboiler connected to the dividing-wall distillation column is 120° C. to 165° C.
1 more element
Dependencies are inferred from the claim text.