METHOD OF SEPARATION OF FUMARIC ACID AND OTHER SIDE COMPONENTS IN OBTAINING MALEIC ACID ANHYDRIDE Russian patent published in 2014 - IPC C07D307/60 

FIELD: chemistry.

SUBSTANCE: method is realised by heterogeneous catalytic oxidation of carbon by molecular oxygen, selected from group of benzol, n-butane, n-butene, in presence of catalyst, which contains vanadium, phosphorus and oxygen, which includes: (a) maleic acid anhydride absorption from impure mixture of products by absorbing agent, which contains organic solvent, in absorption column; (b) desorption of maleic acid anhydride from absorbing agent, which is obtained at stage (a), enriched by maleic acid anhydride, in desorption column; as well as (c) total or partial return to stage (a) of absorbing agent, depleted at stage (b) by content of maelic acid anhydride, is differ in fact, that (d) total or partial quantity of absorbing agent, depleted on stage (b) by content of maelic acid anhydride, for required sedimentation of fumaric acid is cooled and/or subjected to concentration by evaporating absorbing agent to such degree, that difference between concentration of fumaric acid in reverse flow at output from desorption column c (FA, at output from desorption column) at there existing conditions, expressed in weight p/mln, and balanced concentration of fumaric acid, corresponding to solubility curve, after cooling and/or evaporation of absorbing agent part c (FA, balanced, after cooling/steaming), expressed in weight p/mln, constitutes value larger or equal 250 wt, p/mln, and for sedimentation and separation of fumaric acid applied is reservoir with built-in nozzle elements, and average time of staying in reservoir with built-in nozzle elements constitues from 0.05 to 6 hours; (e) fumaric acid, precipitated in form of solid substance due to operations at stage (d), totally or partially, in continuous or periodic mode is removed from reverse flow of absorbing agent; and (f) depleted by content of fumaric acid absorbing agent from stage (e) totally or partially returns on stage (a).

EFFECT: reduction of formation of fumaric acid sedimentations with obtaining maelic acid anhydride.

12 cl, 3 dwg, 5 ex