614-25-5Relevant articles and documents
Efficient and Selective Oxidation of Aromatic Amines to Azoxy Derivatives over Aluminium and Gallium Oxide Catalysts with Nanorod Morphology
Singh, Bhawan,Mandelli, Dalmo,Pescarmona, Paolo P.
, p. 593 - 601 (2019/11/13)
Aluminium oxide and gallium oxide nanorods were identified as highly efficient heterogeneous catalysts for the selective oxidation of aromatic amines to azoxy compounds using hydrogen peroxide as environmentally friendly oxidant. This is the first report of the selective oxidation of aromatic amines to their azoxy derivatives without using transition metal catalysts. Among the tested transition-metal-free oxides, gallium oxide nanorods with small dimensions (9–52 nm length and 3–5 nm width) and fully accessible, high surface area (225 m2 g?1) displayed the best catalytic performance in terms of substrate versatility, activity and azoxybenzene selectivity. Furthermore, the catalyst loading, hydrogen peroxide type (aqueous or anhydrous), and the amount of solvent were tuned to optimise the catalytic performance, which allowed reaching almost full selectivity (98 %) towards azoxybenzene at high aniline conversion (94 %). Reusability tests showed that the gallium oxide nanorod catalyst can be recycled in consecutive runs with complete retention of the original activity and selectivity.
Nb2O5 supported on mixed oxides catalyzed oxidative and photochemical conversion of anilines to azoxybenzenes
De Carvalho, Gustavo Senra Gon?alves,Chagas, Luciano Honorato,Fonseca, Carla Grijó,De Castro, Pedro P?ssa,Sant'Ana, Ant?nio Carlos,Leit?o, Alexandre Amaral,Amarante, Giovanni Wilson
supporting information, p. 5863 - 5871 (2019/04/17)
The synthesis of novel supported niobium oxide catalysts and their application for aniline conversion to azoxybenzenes is described. The catalysts were successfully prepared by thermal decomposition of layered double hydroxides (LDHs), containing M2+ (M = Mg2+ and/or Zn2+) and Al3+ as layer cations, followed by niobium oxide incorporation employing the wetness impregnation method. These catalysts were fully characterized by both experimental techniques and theoretical calculations, and then successfully applied to the selective conversion of anilines into azoxybenzene derivatives, with up to 98% conversion and 92% isolated yield in the presence of violet light. Control experiments and DFT calculations revealed that the catalyst has a dual role in this transformation, acting both as a Lewis acid in the oxidative step and as a photocatalyst in the dimerization of the nitrosobenzene intermediate.
Aromatic amine oxidation process for preparing aromatic liquid discharge method
-
Paragraph 0014; 0015; 0016; 0017; 0018; 0019-0023; 0025, (2017/08/26)
The invention relates to a preparation method for aromatic-azoxybenzene by oxidizing aromatic amine. According to the method, air or oxygen is used as an oxygen source, and aromatic amine is oxidized to be aromatic-azoxybenzene under the effect of metal oxide catalyst. The method has the advantage of high product yield and is easy to separate the catalyst.
