Extractive Catalytic Oxidative Denitrogenation of Fuels and Their Promoting Effect for Desulfurization Catalyzed by Vanadium Substituted Heteropolyacids and Molecular Oxygen

Abstract

In this contribution, we successfully apply our recently developed extractive catalytic oxidative desulfurization technology (ECODS) for the removal of different nitrogen-containing compounds (ECODN) from both gasoline and diesel fuels. Hereby, indole, 1-methylindole, 2-methylindole, 3-methylindole, quinoline, and quinaldine are completely removed from different model fuels under oxidative conditions, i.e., 120 °C and 20 bar oxygen, with the use of an aqueous HPA-5 catalyst solution within minutes. Indole and quinoline species are oxidized selectively to water-soluble compounds such as acetic acid (6−16%), formic acid (4−13%), and oxalic acid (0−4%), which are extracted in situ into the aqueous catalyst solution. Moreover, mainly carbon dioxide (71−86%) is formed in the gas phase. Our catalyst system is also very effective for denitrogenation at ambient conditions. In contrast to the removal of N-compounds at 120 °C and 20 bar oxygen, the reaction at 25 °C and atmospheric pressure produces solid Ncontaining compounds. By combining ECODS and ECODN in one vessel, desulfurization and denitrogenation of different model oils is possible in parallel. Interestingly, N-compounds present in the fuel are found to significantly promote the desulfurization reaction.

Removing Simultaneously Sulfur and Nitrogen from Fuel under a Sustainable Oxidative Catalytic System

“…In particular, Keggin-type POMs ([X n+ M 12 O 40 ] (8-n)-(X: block p or d heteroatom) have been successfully used as efficient catalysts in ODS processes [31][32][33][34][35]. However, the investigation combining ODS and ODN is in a primitive stage and only one publication could be found in the literature demonstrating the ability of POMs as catalysts in this mixed systems [36].…”

Investigations on Catalyst Stability and Product Isolation in the Extractive Oxidative Desulfurization of Fuels Using Polyoxometalates and Molecular Oxygen

“…However, water has not been used extensively as extracting agent in ODS due to the very low solubility of sulfoxides/sulfones in aqueous media. To overcome this problem, we have developed a new alternative approach for ODS called extraction‐coupled oxidative desulfurization (ECODS) ,. In this process, the sulfur contaminants in the fuel (benzthiophene, dibenzothiophene and its alkylated derivatives) are oxidized with an aqueous V−Mo−P Keggin polyoxometalate solution to water‐soluble species which are extracted in situ into the aqueous catalyst phase.…”

Oxidative Desulfurization of Liquid Fuels Using Polyoxometalate-Based Catalysts: A Review

“…Bertleff et al suggested that a catalytic system consisting of HPA-5 (H 8 PV 5 Mo 7 O 40 ) catalyst and O 2 oxidant could remove 80% of the S-compounds (mixture of DBT, BT, and 4,6-DMDBT) from model oil (tetradecane) under reaction conditions (reaction temperature of 120 °C, reaction time 24 h, and 20 bar O 2 ).…”