METHOD FOR PREPARING ETHANOLAMINES Russian patent published in 2004 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to methods for preparing ethanolamines, in particular, to preparing monoethanolamine and/or diethanolamine that are used widely for treatment of natural and industrial gases, in manufacturing detergents and cleansing agents, in paint and varnish, cement, perfume and other branches of industry. The most demand falls to monoethanolamine (MEA) and diethanolamine (DEA) used for treatment of gases. Method involves interaction of ethylene oxide (EO) with stoichiometric excess of ammonia in mixing reactor at enhanced temperature and pressure followed by distilling off and recovery of ammonia excess. Synthesis is carried out in system including mixing and displacement reactors at temperature 70-85 C, under pressure 35-46 atm, in the mole ratio EO : NH₃ = 1:(15-25) and in the conversion index for ethylene oxide in mixing device 70%, not less. Ammonia distilling off recovering for synthesis is carried out at temperature 90-110 C. Preferably, recovery of MEA is carried out in the ratio EO : MEA = 1.0:(0.1-1.0). Method provides alteration the ratio of prepared ethanolamines increasing the yield of MEA and/or DEA depending on demand. Soft conditions for carrying out synthesis and distillation of NH₃ allow to obtain mixtures of products in outlet of reaction system with minimal color index (less 30 U by Hazen). EFFECT: improved preparing method. 2 cl, 1 tbl, 1 sch, 1 ex