Process for preparing ethanolamine with improved colour

Abstract

The present invention relates to a process for preparing an ethanolamine having an improved colour quality. The process comprises contacting ethanolamine with an activated carbon free of one or more metals chosen from Re, Ru, Rh, Pd, Os, Ir, Pt and Ag. The contacting can be carried out at a temperature of from 10 to 200° C., and during a period sufficient to reduce the colour of the ethanolamine, in particular a period such that the colour index (as measured according to the ASTM standard D 1209) of the ethanolamine becomes equal to or less than 50 or 40 Pt/Co. The contacting can be carried out during or after the stage of preparation of the ethanolamine, preferably during or after the stage of purification of the ethanolamine. The invention also relates to a process for manufacturing a triethanolamine (TEA) having an improved colour quality, comprising a stage (i) of synthesis of the TEA by contacting ammonia with ethylene oxide in aqueous medium, a stage (ii) of separation of a crude TEA from the aqueous medium and a stage (iii) of purification of the TEA by distillation. The process in addition comprises contacting the crude or purified TEA with an activated carbon free of one or more metals chosen from Re, Ru, Rh, Pd, Os, Ir, Pt and Ag, after the separation stage (ii), or during and after the purification stage (iii). The advantage of the claimed invention is provide an ethanolamine which has an improved colour quality far more resistant over time, and which is obtained in the absence of any additive or metal catalyst known to contaminate the ethanolamine.

Dependencies are inferred from the claim text.