Study of anthraquinone reaction with sodium sulphide

Abstract

The reduction of anthraquinone (AQ) with sodium sulphide in alkaline medium has been studied by measuring conversion as a function of time at various temperatures, sodium sulphide concentrations, initial radii of anthraquinone particles and sodium hydroxide concentrations. The reduced product is the disodium salt of 9,10-dihydroxyanthracene. The kinetic data were fitted to the isothermal shrinking core model (SCM) for cylindrical particles without porous solid product layer formation. The results indicate that the surface chemical reaction is the controlling step of the overall process rate. AQ reduction is of first order with respect to sodium sulphide concentration. The activation energy was obtained from the Arrhenius law and was found to be 68.81 kJ mol⁻¹ for the investigated temperature range.