Method for Recovering Di-Trimethylolpropane and Trimethylolpropane-Enriched Product Streams from the Side Streams of Trimethylolpropane Production

摘要

Process for obtaining ditrimethylolpropane and trimethylolpropane-enriched product streams from the high-boiling fractions and residues which are obtained in the distillative purification of trimethylolpropane, characterized in that these high-boiling fractions and residues are combined and a polar solvent is added to produce a solution and the solution is treated at a temperature of 120 to 280° C. and at a pressure of 2 to 25 MPa with hydrogen in the presence of a solid nickel catalyst and an acidic compound. After catalytic treatment, the solution is subjected to multi-stage distillation including with a thin film evaporator with a column attachment in order to recover ditrimethylolpropane and trimethylolpropane-enriched product streams.

主权项

1. Process for obtaining ditrimethylolpropane and trimethylolpropane-enriched product streams from the high-boiling fractions and residues which are obtained in the distillative purification of trimethylolpropane, characterized in that:
(a) these high-boiling fractions and residues are combined and a polar solvent is added to produce a solution; (b) the solution produced according to step a) is treated at a temperature of 120 to 280° C. and at a pressure of 2 to 25 MPa with hydrogen in the presence of a solid nickel catalyst and of an acidic compound; (c) the solution obtained according to step b) is removed from the catalyst and further solids, if present; (d) the solution obtained according to step c) is separated in a first distillation unit into a tops fraction comprising the polar solvent and low boilers and into a bottoms fraction with a content of the polar solvent up to 5000 ppm by weight, based on the bottoms fraction; (e) the bottoms fraction obtained according to step d) is supplied to a second distillation unit with at least 5 theoretical plates and a trimethylolpropane-enriched tops fraction is drawn off and a bottoms fraction is withdrawn; and (f) the bottoms fraction obtained according to step e) is supplied to a third distillation unit with at least 4 theoretical plates, in which ditrimethylolpropane is obtained as the tops fraction and high boilers are removed as the bottoms fraction.