Co6Al2HT hydrotalcite-like compounds were synthesized by three different methods: co-precipitation, microwaves-assisted and ultrasound-assisted methods. The mixed oxides obtained after calcination were studied by several techniques: XRD, TEM, H2-TPR and XPS. They were also tested as catalysts in the reaction of total oxidation of toluene. The physico-chemical studies revealed a modification of the structural characteristics (surface area, morphology) as well as of the reducibility of the formed mixed oxides. The solid prepared by microwaves-assisted synthesis was the most active. Furthermore, a relationship between the ratio of Co 2+ on the surface, the reducibility of the Co-Al mixed oxide and the T50 in toluene oxidation was demonstrated. This suggests a Mars Van Krevelen mechanism for toluene total oxidation on these catalysts.

Reactions of 2‐chloroformylhydrazones of aromatic aldehydes or ketones 2 with various hydrazines were converted to monocarbonohydrazone derivatives 3 or 5 and/or tetrahydro‐1,2,4,5‐tetrazin‐3(2H)‐one derivatives 6, 7. By oxidation with lead dioxide, compounds 6 were transformed into stable 3,4‐dihydro‐3‐oxo‐1,2,4,5‐tetrazin‐1(2H)‐yl radical derivatives 8.

X6Al2HT hydrotalcites, where X represents Fe, Cu, Zn, Ni, Co, Mn or Mg, were synthesized as precursors of catalysts for the toluene and CO total oxidation reactions. Specific area, Fourier transformed infrared spectroscopy analysis, XRD measurements and Thermal analysis of these dried solids were performed. After calcination at 500 °C, different mixed oxides were obtained. The structural analysis (XRD, FTIR) and specific areas of these solids were done. Concerning the total oxidation of toluene, the best activity is obtained with Mn6Al2HT catalyst with T50 at 249 °C. X6Al2 nano‐oxides synthesized using hydrotalcite‐type solids as precursors, are then very promising candidates for an utilisation as CO and VOC oxidation catalysts. The nature of bivalent cation in these compounds is essential for the efficacy of the catalyst.

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