Abstract: Process for separating triethanolamine continuously by distillation from a mixture of monoethanolamine, diethanolamine and triethanolamine together with ethanolamine ethers and water obtained by reaction of ammonia with ethylene oxide in the liquid phase under superatmospheric pressure and at elevated temperature, in which the mixture is distilled in two stages. The low-boiling fraction and the high-boiling fraction are taken off and discharged in the first stage and the intermediate-boiling fraction comprising >99.4% by weight of triethanolamine and <0.2% by weight of diethanolamine is distilled in the second stage. The distillation of the mixture is preferably carried out in a first column and a second column connected to this or in a dividing wall column.

Abstract: Method of purifying triethanolamine prepared by reacting aqueous ammonia with ethylene oxide in the liquid phase under pressure and at elevated temperature by removing excess ammonia, water and monoethanolamine from the reaction product, reacting the resulting crude product with ethylene oxide at temperatures of from 110 to 180° C., and then rectifying the mixture in the presence of phosphorous or hypophosphorous acid or compounds thereof.

Abstract: Preparation of alkanolamines having improved color quality by treating the alkanolamine with an effective amount of phosphorous acid or hypophosphorous acid or compounds thereof initially at elevated temperature over a period of at least 5 min (step a), and then distilling it in the presence of an effective amount of one of these phosphorus compounds (step b).

Abstract: Preparation of alkanolamines having improved color quality by treating the alkanolamine with an effective amount of phosphorous acid or hypophosphorous acid or compounds thereof initially at elevated temperature over a period of at least 5 min (step a), and then distilling it in the presence of an effective amount of one of these phosphorus compounds (step b).

Abstract: Preparation of alkanolamines having improved color quality by treating the alkanolamine with hydrogen in the presence of a hydrogenation catalyst at elevated temperature, by using, as hydrogenation catalyst, a heterogeneous catalyst comprising Re, Ru, Rh, Pd, Os, Ir, Pt and/or Ag and a support material chosen from the group consisting of activated carbon, alpha-aluminum oxide, zirconium dioxide and titanium dioxide, where the catalyst, in the case of activated carbon as support material, has a cutting hardness of at least 10 N, a side crushing strength of at least 30 N or a compressive strength of at least 25 N.

Abstract: A process for the preparation of a color-stable dialkylaminoethanol of the formula ##STR1## in which R.sup.1 and R.sup.2 independently are C.sub.1 -C.sub.20 -alkyl, by reacting ethylene oxide with a dialkylamine of the formula HNR.sup.1 R.sup.2, in which R.sup.1 and R.sup.2 have the same meaning, in the presence of from 2.5 to 50% by weight of water, based on the reaction mixture, at a temperature of from 95.degree. to 170.degree. C., and separating off the water and high-boiling constituents by distillation under a reduced pressure and at a temperature of from 40.degree. to 90.degree. C. at the column bottom.