Abstract: The invention relates to a process for evaporating a liquid containing vaporizable oxidation-sensitive compounds in an evaporator in which the liquid is brought into contact with a heated solid surface for evaporation, by a process in which direct contact between the resulting vapor phase and the heated solid surface is substantially avoided. It also directed to an evaporator composed of a heatable solid surface (16), an apparatus (2, 3) for heating the solid surface and an apparatus (10) for feeding a liquid containing vaporizable compounds to the heatable solid surface, wherein the apparatus for feeding the liquid is designed and arranged in the evaporator in such a way (12, 14, 18) that direct contact between a resulting vapor phase and the heatable solid surface is substantially avoided.

Abstract: Neopentyl glycol hydroxypivalate (NGH) is isolated from a mixture containing NGH, lower- and higher-boiling products and inorganic salts and purified in a two-stage process, whereinin a first separation stage, the inorganic salts and part of the higher-boiling products are separated off in a wiped-film evaporator and a vapor stream consisting of NGH, lower- and higher-boiling products is discharged and fed to a heat exchanger and condensed therein,and, in a second separation stage, the resulting condensate is distilled in a rectification column from which NGH is taken off in a side stream and condensed. Further discharges of the rectification column containing lower-boiling products or higher-boiling products are separately taken off. The higher-boiling products which comprise residual NGH are partly or completely recycled to the lower region of the rectification column.