Synthesis,Characterization And Catalytic Activity Of Vanadium(V) Complexes Of Hydrazone Ligands

Catalytic oxidation of cyclohexane is an important chemical industrial process.Cyclohexanol and cyclohexanone are the main products of this reaction,hich are the main ra materials for the synthesis of adipic acid and caprolactam,and nylon-6,6,nylon-6 can be further synthesized.he C-H bond dissociation of cyclohexane is sufficiently high and the C-H bond is difficult to brea?,hich is a challenge in chemical industrial production.In the traditional industrial production of cyclohexane oxidation,there are problems such as lo selectivity,high temperature,high pressure,and many by-products,resulting in aste of resources and environmental pollution.his requires the design of a ne catalyst to catalyze the oxidation of Cy under mild conditions,and increase product yield hile ensuring that the by-products produced are not harmful to the environment.In this paper,six hydrazide vanadium Schiff base complexes ere synthesized[VOL¹(OMe)(Me OH)](1),[VOL²(OMe)(Me OH)](2),[VOL³(AHA)](3),[VOL⁴(AHA)]?Me OH(4),[VOL⁵L⁶].Me OH(5),[VOL⁶L⁷].Me OH(6)(H₂L¹=N'-(4-bromo-2-hydroxybenzylidene)-2-chlorobenzohydrazide,H₂L²=4-bromo-N'-(2-hydroxy-4-methoxy benzylidene)benzohydrazide,H₂L³=2-bromo-N'-(3-ethoxy-2-hydroxybenzylidene)benzohydrazide,H₂L⁴=N'-(5-chloro-2-hydroxybenzylidene)-4-methylbenzohydrazide,AHA=aceto hydroxamic acid,H₂L⁵=N'-(3-bromo-5-chloro-2-hydroxybenzylidene)-3-hydroxyl-4-methoxybenzohydrazide,HL⁶=2-Ethyl-3-hydroxy-4H-pyran-4-one,H₂L⁷=N'-(2-hydroxy-5-nitrogenbenzylidene)-3-hydroxyl-4-methoxy benzohydrazide).Among them,complexes 1,5and 6 ere synthesized for the first time and characterized by infrared spectroscopy,ultraviolet spectroscopy and thermogravimetric analysis.he crystal structure as determined by X-ray single crystal diffraction method,indicating that the complexes 1,5 and 6 are all hexagonal octahedral configurations.he complex 1 is a dimer formed by hydrogen bonding bet een adjacent molecules,and the complexes 5 and 6 are layered.he activity of the hydrazide vanadium Schiff base complex in the catalytic oxidation of cyclohexane as investigated.he conditions affecting the catalytic oxidation of cyclohexane are optimized,such as the amount of catalyst,H₂O₂,ater and nitric acid,as ell as the type of solvent,acid and the volume,time,temperature.he effect of additives on the catalytic oxidation of cyclohexane as discussed ith complex 3 as catalyst.It as found that the mixed acid promoter of sulfuric acid and salicylic acid can promot the catalytic oxidation of cyclohexane.With complex 5 as the catalyst under the optimal conditions,the influence of temperature on the catalytic effect of nitric acid and sulfuric acid as acid additives was discussed.