Abstract: Provided is a method for producing an isocyanate compound, including a step (1) of reacting a primary amine compound with a carbonic acid derivative to obtain an N-substituted carbamate compound while extracting a by-product compound having a boiling point lower than a boiling point of the N-substituted carbamate compound, a step (2) of performing thermal decomposition of the N-substituted carbamate compound on a reaction solution obtained in the step (1) in the presence of an aprotic solvent to obtain an isocyanate compound while extracting a by-product hydroxy compound, a step (3) of separating the isocyanate compound and the aprotic solvent from a reaction solution obtained in the step (2), and a step (4) of removing a component having a boiling point higher than a boiling point of the isocyanate compound from a fraction obtained in the step (3) to purify the isocyanate compound.

Abstract: This isocyanate production method, for continuously producing an isocyanate while suppressing side reactions, is a method for producing an isocyanate through the thermal decomposition of carbamate, and comprises: a thermal decomposition step in which a mixed solution containing carbamate and a compound (A) having a specific structure is continuously put into a pyrolysis reactor and carry out a pyrolysis reaction of carbamate; a low-boiling-point decomposition product recovery step in which a low-boiling-point decomposition product having a lower standard boiling point than the compound (A) is continuously extracted in a gaseous form from the pyrolysis reactor, and a high-boiling-point component recovery step in which a liquid phase component, which is not recovered in a gaseous form in the low-boiling-point decomposition product recovery step, is continuously extracted as a high-boiling-point component from the pyrolysis reactor.