Patent ID: 8445726

Claim:
A process for preparing an unsymmetric secondary tert-butylamine of the formula I by reductively aminating an aldehyde of the formula II with tert-butylamine and hydrogen in the liquid phase in the presence of a hydrogenation catalyst, comprising: (i) providing tert-butylamine and the hydrogenation catalyst in a pressure vessel, (ii) adding hydrogen and continuously adding an aldehyde of the formula II R—CHO II where R is selected from the group of hydrogen, a linear or branched aliphatic radical having 1 to 15 carbon atoms, a cycloaliphatic radical having 5 to 10 carbon atoms, a substituted or unsubstituted phenyl radical, and a phenylalkyl radical, and the ratio of hydrogen to aldehyde of the formula II is at least equimolar, (iii) keeping the temperature during the addition of the aldehyde in (ii) within the range from 50 to 150° C. and keeping the total pressure during the addition of the aldehyde in (ii) within the range from 2 to 120 bar, (iv) dewatering the hydrogenation output from (iii) which comprises the secondary tert-butylamine which is formed and is of the formula I where R is defined above and the water of reaction, and (v) subsequently fractionally distilling the dewatered hydrogenation output from (iv).