Organic amine collection method

A method for collecting a compound of general formula (III) from a liquid phase component that is formed as a by-product in a method for producing a compound of general formula (I), comprising:

• step (A):
• a step for mixing the liquid phase component, water, and the compound of general formula (III);
• step (B):
• a step for reacting the liquid phase component with water in a reactor;
• and
• step (4):
• a step for discharging, as a liquid phase component inside the reactor, the reaction liquid containing the compound of general formula (III) to an outside of the reactor,
• in the general formula (I), R11 represents a monovalent to trivalent organic group, and n11 represents an integer of 1 to 3, and
• in the general formula (III), R31 represents a monovalent to trivalent organic group, and n31 represents an integer of 1 to 3, wherein the liquid phase component that is formed as a by-product in the method for producing the compound of general formula (I) is a liquid phase component extracted from a thermal decomposition reactor when a gas phase component comprising the compound of general formula (I) generated by supplying a liquid containing a carbamate produced from a carbonic acid derivative, a hydroxy compound and the compound of general formula (III) to the thermal decomposition reactor and then subjecting the carbamate to thermal decomposition reaction is collected.