METHOD FOR PURIFYING TRIMETHYLOLPROPANE, WHICH IS PRODUCED BY HYDROGENATION, BY MEANS OF CONTINUOUS DISTILLATION.

摘要

The invention relates to a method for carrying out the pure distillation of trimethylolpropane originating from the hydrogenation of 2,2dimethylolbutanal with the following steps: (a) reacting nbutyraldehyde with formaldehyde in the presence of catalytic quantities of a tertiary amine and hydrogenating the mixture that is obtained in such a manner in order to form a mixture containing trimethylolpropane; (b) separating water, methanol, trialkylamine andor trialkylammonium formate by distillation; (c) heating the remainder obtained in (b), under a vacuum, to a temperature at which TMP is volatile and at which compounds that boil at temperatures greater than that of TMP are cleaved while separating by distillation TMP as well as compounds that are less volatile than TMP; (d) distilling the distillate obtained in (c) while separating out the less volatile compounds and obtaining pure TMP; (e) carrying out the facultative distillation of the TMP obtained in (d) in order to obtain TMP that has a low alpha color index. The invention also relates to a method in which trialkylammonium formate is separated by distillation, while preserving the same, from raw mixtures consisting of polyvalent alcohols, mainly of trimethylolpropane.