Carrier-vapor distillation

摘要

Process for the separation or purification of heat-sensitive compounds by carrier-vapor distillation, wherein the superheated solvent vapor which is loaded with the compound to be distilled is cooled by treatment with condensed solvent in counter-current and the amount of condensed solvent is measured in such a manner that a saturated solution of the compound which is almost at boiling point is formed from the superheated, loaded vapor. The process being especially apted for separating or purifying 4-hydroxybenzaldehydes optionally substituted by one or more C1-C4-alkoxy groups.