Process for the preparation of naphthalene-1,4,5,8-tetracarboxylic acid by oxidation with a peroxy compound

摘要

The invention relates to a process for the preparation of alkali metal salts of naphthalene-1,4,5,8-tetracarboxylic acid by the oxidation of pyrene. The latter is treated, in a lower alkanecarboxylic acid, with an organic hydroperoxide or a percarboxylic acid in the presence of a metal compound, and the resulting intermediate is reacted with chlorine in aqueous alkaline solution. The free naphthalene-1,4,5,8-tetracarboxylic acid is obtained from the alkali metal salts using mineral acids. Most importantly, the process according to the invention makes it possible to avoid the procedural difficulties and serious environmental concerns which are associated with the disposal of substantial quantities of concentrated sulphuric acid which has hitherto been used as the solvent for the pyrene oxidation.