Process for the preparation of at least partially sulfonated naphthalene, and use of this product in the purification of naphthalene.

摘要

1. Process for the preparation of at least partially sulphonated naphthalene by the reaction of sulphuric acid with naphthalene, in the presence of a solvent forming an azeotrope with water, characterised in that the molar ratio sulphuric acid/naphthalene is less than 1 and in that the reaction of the sulphuric acid on the naphthalene is carried out between 90 and 150 degrees C thus totally eliminating water in a continuous manner from the reaction medium by azeotropic distillation by means of a solvent chosen from saturated aliphatic hydrocarbons, saturated cycloaliphatic hydrocarbons or their mixtures so that the product obtained is completely free from water and sulphuric acid.