NICOTINIC ACID PRODUCTION METHOD Russian patent published in 2019 - IPC C07D213/803 C07D213/79 B01J23/22 B01J21/06 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing nicotinic acid by direct gas-phase oxidation of 3-picoline with atmospheric oxygen, in which 3-picoline, air, water and recycle gases are fed into a reactor consisting of tubes with a fixed layer of a granular catalyst washed with a coolant. If the recycle fraction is 70–90 % of the total volume of the reaction mixture, concentration of 3-picoline at the reactor inlet is 0.78–1.1 mol%, and preferably 0.8–1.0 mol%, and the molar ratio of 3-picoline, oxygen and water – 1:/11–21/:/18–26/. Binary vanadium-titanium oxide catalyst is used. Ratio of size of catalyst granules to inner diameter of tube is 1:/5.8–9.3/, and preferably 7.0, and maximum temperature in catalyst layer by 5–20 °C is higher than coolant temperature. After the reactor, the reaction gases are directed to the stage of nicotinic acid release into the solid phase, after which some gases are separated and recycled, and from remaining part of reaction gases either unreacted 3-picoline and 3-pyridinecarbaldehyde are extracted into liquid phase and returned to catalytic process of nicotinic acid production, or the rest part of reaction gases is directed to neutralization and further discharge into atmosphere.

EFFECT: increased removal of nicotinic acid from a unit of weight of the catalyst and increased completeness of using initial 3-picoline.

4 cl, 10 ex