PROCESS FOR THE PREPARATION OF ETHYLENE DIAMINE HAVING LOW WATER CONTENT

摘要

1466941 Removing water from ethylene diamine BEROL KEMI AB 5 March 1974 [7 March 1973] 9905/74 Heading C2C Water is removed from aqueous ethylene diamine containing water in an amount which is greater than the amount of water in the azeotropic mixture formed between ethylene diamine and water by distilling the aqueous ethylene diamine in the presence of at least one distillation additive selected from piperazine, diethylene triamine, N-hydroxyethyl ethylene diamine and N-aminoethyl piperazine until the water content of the mixture is lower than the water content in the azeotropic mixture formed between ethylene diamine and water. The aqueous ethylene diamine may be that obtained by the catalytic amination of monoethanolamine or ethylene glycol with ammonia, the distillation additive being formed as a by-product. The crude ethylene diamine is passed via line 1 into a distillation column 2 operating at or slightly above atmospheric pressure and the major proportion of water is withdrawn from the head of the column whilst ethylene diamine, amino impurities and a little water are withdrawn from the bottom of the column and passed into a distillation column 4 operating under reduced pressure. Amino impurities are withdrawn from the bottom of column 4 whilst ethylene diamine containing a small amount of water is removed from the head of the column and passed into a column 7 also operating under reduced pressure. Anhydrous ethylene diamine is removed from the head of column 8 whilst an azeotropic mixture of ethylene diamine and water is removed from the bottom of the column and recirculated to column 2.