Yakudo Tachibana

Selective oxidation of toluene to benzoic acid catalyzed by modified vanadium oxides

Abstract A variety of oxides were examined as additives to a V 2 O 5 /TiO 2 catalyst in order to enhance the catalytic performance for the vapor phase oxidation of toluene to benzoic acid. It was found that the modification with SeO 2 , TeO 2 or Sb 2 O 3 greatly promoted the title reaction leading to improved catalyst performance in terms of toluene conversion and benzoic acid selectivity. The effect of reaction temperature, O 2 /toluene ratio, steam/toluene ratio and durability were also investigated in order to reveal the catalytic features of the modified catalyst systems.

Vapor-phase oxidation of benzoic acid to phenol over Na2O-promoted NiOFe2O3 catalyst

Abstract A NiO Fe 2 O 3 Na 2 O catalyst achieved an extremely high space-time yield (STY) of phenol, while maintaining a high phenol selectivity, as compared with that of a conventional CuO catalyst for the vapor phase oxidation of benzoic acid. The addition of Na 2 O to NiO Fe 2 O 3 catalyst was found to be very effective in increasing the STY of phenol, while maintaining a high phenol selectivity. The effect of temperature, oxygen ratio, H 2 O ratio, and space velocity on the catalyst performance were examined in order to optimize the phenol selectivity and STY of phenol. The reaction route for phenol formation over the Na 2 O-promoted NiO Fe 2 O 3 catalyst was also speculated upon by considering the deactivation of the catalyst.

Structural analysis of NiO—Fe2O3 catalyst for vaporphase oxidation of benzoic acid to phenol

Abstract NiO-Fe 2 O 3 catalyst with an atomic ratio of nickel to iron of one was found to show excellent activity for vapor-phase oxidation of benzoic acid to phenol. The homogeneous distribution profile of NiO and NiFe 2 O 4 on the surface and in the bulk of the catalyst is essential for the formation of phenol.

A highly effective countermeasure for the deactivation of the NiONiFe2O4Na2O catalyst for phenol synthesis

Abstract Durability of the novel catalyst system for phenol synthesis by vapor phase oxidation of benzoic acid was investigated in detail. Although an obvious deactivation was observed using the NiO NiFe 2 O 4 Na 2 O system, prominent results were obtained by the addition of V 2 O 5 to the catalyst. More than 90% both in phenol selectivity and benzoic acid conversion were maintained more than 100 h. The remarkable enhancement of catalytic performance is considered to be derived from the facilitated reoxidation of active species by V 2 O 5 in its redox cycle.

Oxidation of toluene to benzoic acid over modified V2O5-TiO2 catalyst with SeO2, TeO2 and Sb2O3

It was found that the addition of SeO2, TeO2 or Sb2O3 to a V2O5/TiO2 catalyst greatly improved the catalytic activity in the vapor phase oxidation of toluene to selectively form benzoic acid.

Vapour phase oxidation of benzoic acid to phenol over NiO–Fe2O3 catalysts

The NiO–Fe2O3 complex oxide catalysts, which were prepared by precipitation and then calcined at around 800 °C, showed excellent catalytic activity in the vapour phase oxidation of benzoic acid to selectively form phenol.

Alkali-promoted NiO–Fe2O3 catalysts for vapour-phase oxidation of benzoic acid to phenol

Addition of Na2O to the NiO–Fe2O3 catalyst system was found to be very effective for increasing the space-time yield for phenol while maintaining highphenl selectivity; a reaction route to phenol formation via sodium benzoate is proposed.

Effect of added V2O5 on the durability of NiO–Fe2O3–Na2O catalyst in vapour phase oxidation of benzoic acid to phenol

Addition of V2O5 to NiO–Fe2O3–Na2O catalyst is effective for preventing catalyst deactivation which is caused by the accumulation of sodium benzoate on the catalyst surface.