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 oxygen or air enriched with oxygen, in which 3-picoline, oxygen, water and recycle gases are fed into a reactor consisting of tubes with a fixed layer of a granular catalyst washed with a coolant. At recycle fraction of 88–93 % of total volume of reaction mixture, concentration of 3-picoline at reactor inlet is 2.5–3.0 mol%, and molar ratio of 3-picoline, oxygen and water is 1:/11–21/:/17–26/. Used binary vanadium-titanium oxide catalyst. Ratio of size of catalyst granules to inner diameter of tube is 1:(5.8–8.4), and maximum temperature in catalyst layer is 5–25 °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 the other part of reaction gases either unreacted 3-picoline and 3-pyridinecarbaldehyde are recovered into the liquid phase and returned to the catalytic process of producing nicotinic acid, or another part of the reaction gases is directed to neutralization and then discharged 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, 9 ex