Immobilized VO–Schiff Base Complex on Modified Graphene Oxide Nanosheets as an Efficient and Recyclable Heterogeneous Catalyst in Deep Desulfurization of Model Oil

Maryam Abdi,Zeinab Moradi-Shoeili,Mohammad Ghadermazi,Abdollah Fallah Shojaei

doi:10.17344/acsi.2019.5466

Maryam Abdi, Zeinab Moradi-Shoeili + Show 2 more

Open Access

https://doi.org/10.17344/acsi.2019.5466

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Abstract

New heterogeneous catalyst was synthesized via covalent anchoring of oxovanadium(IV) complex of 5,5?-dibromobis(salicyledene)diethylenetriamine (VO[5-Br(Saldien)]) on the surface of chloro-modified graphene oxide (GO@CTS). The structure of the catalyst was investigated using different characterization techniques such as XRD, SEM, EDX, FT-IR, TG, DTA and ICP-AES analyses. The synthesized heterogeneous oxovanadium(IV) was an efficient catalyst for high yield and selective oxidation desulfurization (ODS) of dibenzothiophene (DBT) as a model oil using H2O2 as oxidant and formic acid as a promoter. The effects of the catalyst mass, reaction temperature and time, formic acid/H2O2 ratio and molar ratio of H2O2 to the total amount of sulfur (O/S) on oxidation desulfurization activity were investigated. Moreover, the prepared catalyst can be easily separated from the reaction mixture and reused six times without a significant loss of catalytic activity and selectivity.

Highlights

Growing energy demand will be accompanied by growing greenhouse gas (GHG) emissions e.g. CO2 with an impact on climate change and non-GHG emissions e.g. NOx, SO2, volatile organic compounds and particulate materials with an impact on local air quality.[1]
The results clearly demonstrated the presence of vanadium in the synthesized heterogeneous catalyst, Graphene oxide (GO)@5-Br(Saldien)VO
The results indicated that of GO@5-Br(Saldien)VO was quite reliable for oxidation desulfurization (ODS) in comparison with other catalysts

Summary

Introduction

Growing energy demand will be accompanied by growing greenhouse gas (GHG) emissions e.g. CO2 with an impact on climate change and non-GHG emissions e.g. NOx, SO2, volatile organic compounds and particulate materials with an impact on local air quality.[1]. Results showed that the immobilization of homogeneous complexes onto the polystyrene support enhances their stability and catalytic reactions are heterogeneous in nature.[26] Ogunlaja and coworkers reported a continuous flow system for oxidative desulfurization of refractory organosulfur compounds by two oxovanadium(IV) polymer supported catalysts.[23] Graphene oxide (GO) has attracted considerable attention as one of the most promising supports to immobilize homogeneous vanadium complexes.[27] Mungse et al reported the covalent anchoring of an oxovanadium Schiff base complex onto GO nanosheets for the oxidation of various alcohols, diols, and α-hydroxyketones to carbonyl compounds using tert-butylhydroperoxide (TBHP) as an oxidant.[28] Verma et al reported that oxovanadium Schiff base supported graphene oxide exhibited a higher catalytic efficiency than the homogeneous vanadyl acetylacetonate for epoxidation of fatty acids and esters.[29] Hajjar and coworkers reported the application of nano-graphene sheet supported Co and Mo species in the HDS process. The prepared catalyst was successfully reused for six runs without a significant loss in catalytic activity

Experimental

Results and Discussion

2. Evaluation of Catalytic Activity

Conclusions