METHOD OF PREPARING HIGH PURITY ACRYLIC ACID (VARIANTS) Russian patent published in 2000 - IPC

FIELD: chemical industry. SUBSTANCE: described is method of preparing highly pure acrylic acid (variants) having residual content of aldehydes of less than 10 ppm by fractional distillation oat temperatures from 25 to 1000 C with addition of amino compound selected from group consisting of group A which is primary aryl amine of formula IV wherein X₃ is selected from -COOH and -COOR⁶ wherein R⁶ is C₁-C₆ alkyl, alkanol amine of formula HO-R⁷-NH₂ wherein R⁷- is C₂-C₆-alkylene; groups B-o-m p-phenylene diamine, 4-nitro phenyl hydrazine, 2,4-dinitrophenyl hydrozine; groups S-ortho-or meta-toluidine; groups P-o- m, p-phenylene diamine, 4-nitrophenyl hydrazine, 2,4- dinitrophenyl hydrazine, phenyl hydrazine, hydrazine, aniline. In these methods, amines of selected groups are used consecutively, preferably continuously with selective reduction in content of acrolein and furfurol, and process is carried out in the presence of maleic acid and maleic anhydride as admixtures. EFFECT: economical continuous process of reducing concentration of aldehydes in crude acrylic acid in preparing highly pure acrylic acid. 5 cl, 12 tbl