Method of removing nitrate compounds from adipic acid

A method of removing a nitrate compound from solid adipic acid, said method comprising:

• i) contacting solid adipic acid comprising a nitrate compound with a gas, wherein the contacting takes place at a temperature in a range of above 85° C. to 95° C.,
• wherein i) is either:
• a) not followed by any further contacting of the solid adipic acid with a gas wherein the further contacting takes place at a temperature higher than the temperature of i), or
• b) followed by further contacting the solid adipic acid with a gas wherein the further contacting takes place at a temperature that is above the temperature of i) above 95° C., but below 100° C.