Patent ID: 7211701
Filing Date: 2007-05-01
Classification: B01D,C07C

Abstract:
1. Process for preparing trimethylolpropane having a low APHA colour number, comprising: a) reacting n-butyraldehyde and/or 2,2-dimethylolbutyraldehyde with formaldehyde in the presence of an inorganic base to give trimethylolpropane-containing reaction mixtures, b) removing water and inorganic salts at least partially from the trimethylolpropane-containing reaction mixture obtained in a) to recover crude trimethylolpropane and c) separating the crude trimethylolpropane obtained from b) by distillation into one or more low boiler fractions, one or more predominantly trimethylolpropane-containing medium boiler fractions and one or more high boiler fractions whereby, during the distillation, one or more low boiler fractions and one or more predominantly trimethylolpropane-containing medium boiler fractions are simultaneously withdrawn.