Technology of producing nicotinic acid with nicotinamide concentrated acid crystals

The invention provides a technology of producing nicotinic acid with nicotinamide concentrated acid crystals and relates to the field of nicotinic acid production and preparation. The technology comprises the following steps of putting a nicotinamide solution, primary return fluid and secondary return fluid in a reactor, performing stirring with temperature rising at a T1 temperature, dropwise adding a aqueous alkali return flow at the same time, stopping stirring after 80-100min, and performing cooling to T2 at a speed of 5 DEG C/min; performing vacuum suction filtration on a mixture in the reactor after 2-3h, performing solid-liquid separation, enabling a liquid part to reflux into the reactor as the primary return flow, collecting a solid part, washing the solid part for 2-3 times, andperforming stirring drying to obtain crude crystals; and heating and stirring the crude crystals and absolute ethyl alcohol, performing cooling for recrystallization, performing filtering and washingagain after 4-5h, enabling