GB1047259A - - Google Patents

Abstract

In a cyclic redox process for the production o H2O2 from anthraquinone derivatives e.g. 2 ethyl anthraquinone and tetrahydro-2-ethy anthraquinone in the presence of a silicate-containing catalyst, the latter is reactivated as necessary by washing with an organic solvent or mixture thereof and subsequently drying between 100 DEG C. and temperatures at which the particle structure of the silicate is altered. Comparative examples are given to demonstrate the efficiency of reactivated catalysts. ALSO: In a process for the reactivation of a silicate containing catalyst which has been employed in a cyclic process (i.e. a redox system involving the use of anthraquinone or derivative thereof) for the production of H2O2, the spent catalyst is revivified by washing with an organic solvent or organic solvent mixture (as hereinafter defined), the solvent is removed from the washed catalyst and the catalyst is heated above 100 DEG C. but below temperatures at which catalyst particle structure is changed. The catalyst may be sodium aluminium silicate. The solvent or solvent mixture is defined as one capable of dissolving anthraquinone and quinol constituents and having a boiling point above washing temperature. Residual solvent may be removed from the catalyst by blowing steam therethrough or heating in an oven on trays e.g. in nitrogen or in vacuo.