Triphenyl methyl phosphonium tosylate as an efficient phase transfer catalyst for ultrasound-assisted oxidative desulfurization of liquid fuel

• Published in: Environmental science and pollution research international 2021-06, Vol.28 (21), p.26747-26761
• Main Authors: Desai, Komal, Dharaskar, Swapnil, Khalid, Mohammad, Gupta, Thummalapalli Chandra Sekhara Manikyam
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Catalysts; Conversion; Desulfurization; Desulfurizing; Dibenzothiophene; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Hydrogen peroxide; Ionic liquids; Ions; Irradiation; Liquid fuels; Oxidants; Oxidation; Oxidizing agents; Phase transfer catalysts; Process parameters; Radiation; Reaction time; Research Article; Sulfur; Sulfur compounds; Ultrasonic imaging; Ultrasound; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-021-12391-1

The novel phosphonium-based ionic liquid (IL), triphenyl methyl phosphonium tosylate ([TPMP][Tos]), has been synthesized and applied as a phase transfer catalyst (PTC) in the ultrasound-assisted oxidative desulfurization (UAODS). Oxidation of model fuel (MF) containing dibenzothiophene (DBT) was carried out using an equimolar mixture of H 2 O 2 -CH 3 COOH as an oxidant at 40–70 °C in the presence of IL. The sulfur compound is converted into polar sulfone, and the maximum desulfurization efficiency was examined. The effect of process parameters such as reaction temperature, reaction time, molar ratio of oxidant to sulfur (n(O/S)), and the mass ratio of ionic liquid to model fuel (m(IL/MF)) was studied, and the conditions for maximizing the DBT conversion rate were found. Maximum conversion (> 99%) was obtained at a temperature of 70 °C with m(IL/MF) of 0.8. The oxidation reactivity of various sulfur compounds was studied at different time intervals. To verify the effect of ionic liquid and ultrasound irradiation, extractive desulfurization (EDS), oxidative desulfurization (ODS), and UAODS in the presence of IL were carried out. The experimental results show that the UAODS process gives the highest desulfurization efficiency. A kinetic study was performed to estimate the rate constant and the order of oxidation reaction.