| 摘要 |
Anhydrous ethylenediamine or high concentration ethylenediamine solutions are obtained from aqueous ethylenediamine solutions by contacting aqueous NaOH with a vaporized ethylenediamine solution by flowing them countercurrent through a column so as to obtain at the top vapours with an amine concentration above the azeotropic value, and rectifying said vapours in a conventional rectification column. The product from the foot of the rectification column may be recycled. Subatmospheric pressures or atmospheric pressure may be used.
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