VERFAHREN ZUR HYDROLYSE VON (ALPHA)-NAPHTALINSULFONSAEURE IN EINEM NAHPTALIN-SULFONIERGEMISCH

摘要

The invention relates to a process for the hydrolysis of alpha-naphthalene sulphonic acid in a naphthalene-sulphonating mixture by treatment with water vapour. Here, the sulphonating mixture is added to the head of a scrubbing column, brought into contact with a reverse current of water vapour and the product is taken to the head of the scrubbing column until the total quantity of sulphonating mixture added to the head of the column is at least as great as the quantity to be cleaned and the total time spent by the sulphonating mixture in the column is at least 15 minutes.