Patent ID: 7683216

Claim:
A process for preparing at least one alkyleneimine, comprising: a first heating of a mixture comprising at least one sulfuric acid monoester of aminoalkanol and at least one aqueous base to a temperature of at least 100° C.; a first reacting of said at least one sulfuric acid monoester of aminoalkanol and said at least one aqueous base which is carried out at said temperature and at a pressure of at least 3 bar to form said at least one alkyleneimine; a first depressurizing of said mixture; a first separating of said at least one alkyleneimine from said mixture; a second reacting of said at least one sulfuric acid monoester of aminoalkanol and said at least one aqueous base at said temperature and at a pressure of at least 3 bar to form said at least one alkyleneimine; a second depressurizing of said mixture; and a second separating of said at least one alkyleneimine from said mixture, wherein i) said first heating is carried out for no longer than 25% of the total time of said first reacting, ii) from 40 to 90% of said at least one sulfuric acid monoester of aminoalkanol present in said mixture is converted to said at least one alkyleneimine during said first reacting; and iii) from 90 to 99.99% of said at least one sulfuric acid monoester of aminoalkanol present in said mixture is converted to said at least one alkyleneimine during said second reacting.