In situ synthesis of solid base catalysts for the regeneration of degradation products formed during the anthraquinone process for the manufacture of hydrogen peroxide

Abstract

MgAl–CO 3-layered double hydroxides (MgAl-LDHs) have been synthesized on the surface of spherical γ-Al 2O 3 by an in situ synthesis technique using urea as a precipitant. After calcination, LDH crystallites are transformed into complex metal oxides (LDO) with high homogeneity and MgAl-LDO/γ-Al 2O 3 solid base catalysts containing different LDO content were obtained. X-ray diffraction, scanning electron microscopy, and surface area measurements using the Brunauer–Emmett–Teller method indicated that the MgAl-LDO/γ-Al 2O 3 catalysts possess high specific surface area and rich mesoporous structure. The MgAl-LDO/γ-Al 2O 3 catalysts were used to regenerate anthraquinone degradation products formed in the anthraquinone process for the manufacture of hydrogen peroxide. The efficiency of regeneration of the anthraquinone degradation products was found to increase with increasing LDO loading in the catalysts. Compared with commercial catalysts of NaOH/γ-Al 2O 3 and MgO/γ-Al 2O 3 prepared by the impregnation method, MgAl-LDO/γ-Al 2O 3 catalysts exhibited not only higher activity but also longer life.