Catalytic Oxidation Of Carbazole By Alky Peroxides Over Mo Catalysts

Carbazole(CAR) compounds which are stable account for more than 60%of total nitrogen compounds in petroleum products.Their removal by oxidation is the key in deep denitrogenation.With alkyl peroxides as oxidant,catalytic oxidation of carbazole in model diesel was investigated in anhydrous conditions.Because of unfavorable interaction between sulfur compounds and nitrogen compounds in petroleum refining,the selectivity of the catalytic oxidation system for them was also studied with sulfur compounds represented by dibenzothiophen(DBT).The oxidation of CAR in decalin solution was performed with oil-soluble t-butyl hydrogen peroxide(TBHP) as oxidant in the present of Mo catalysts.The effect on carbazole conversation was investigated from several aspects:ligand of catalyst,support,incorporation of Ni and Co in catalysts.The conditions in TBHP/MoO₃/D113(D751) system were optimized. Under optimal conditions,CAR's conversion reached 74.3%(67.6%).The oxidation product was speculated as carbazole 1-4 dione dipolymer through IR,and ¹H-NMR spectra.Catalytic oxidation of DBT under alkyl peroxide / Mo catalyst system was studied.The impacts on convertion were discussed from these aspects:structure of alkyl peroxide,catalysts carrier,and inorporation of other metals.The oxidative conditions of CAR and DBT were compared and it was found that the oxidation of CAR was harder than DBT,steric hindrance playde an imprtant role in oxidation of CAR while electronic effect was the main factor in DBT's oxidation;and incorporation of Co Ni in MoO₃/Al2O₃ decreased the catalytic activity. In research on the cometion between CAR and DBT,the results showed that in TBHP / MoO₃ /D751 catalytic system there wasn't inhibition between each other and the highest convertions CAR and DBT were up to 63.2%and 99.5%which were slightly lower than the conversion in their individual oxidation,but unfortunately the two exhibits unfavorable effet on each other in TBHP/MoO₃/D113.Oxidation mechanism of DBT was discussed and the oxidation course of CAR was conjuectured.