Metal-Free Oxidative Desulfurization Catalysts Based on Porous Aromatic Frameworks

Abstract

Porous aromatic frameworks modified by sulfonic groups were synthesized and, for the first time, applied for the oxidative desulfurization of a model and a real fuel. The main factors affecting the process including the catalyst dosage, temperature, reaction time, oxidant dosage, and hydrogen peroxide concentration were investigated in detail. Under optimal conditions, dibenzothiophene (DBT) was removed completely. It was shown that the synthesized catalysts reduced the sulfur content in the straight-run gasoline fraction up to ultra-low values (7 ppm). Fuel fractions and their oxidation products were analyzed by two-dimensional gas chromatography with time-of-flight mass spectrometry detection. No byproducts of hydrocarbon oxidation were found, which confirms the high selectivity of oxidation in the presence of synthesized catalysts. These catalysts retain their activity in DBT oxidation for at least five cycles.

New Type of Catalyst for Efficient Aerobic Oxidative Desulfurization Based On Tungsten Carbide Synthesized by the Microwave Method

“… 10 − 13 Among these alternative approaches, the method of oxidative desulfurization attracts the greatest interest of researchers because of this technique’s capability of reducing the sulfur content in various petroleum fractions down to ultra-low values with sufficiently high selectivity. 14 In this case, the reaction products, sulfones, can be selectively recovered and used in various industries and agriculture. 15 , 16 …”

“…Thus, today, it is urgent to search for alternative non-hydrogen methods to reduce the sulfur content in oil products, allowing efficient desulfurization with minimal waste generation. The following anhydrous methods are known from the literature: extraction, , adsorption, , biodesulfurization, , and oxidative desulfurization. − Among these alternative approaches, the method of oxidative desulfurization attracts the greatest interest of researchers because of this technique’s capability of reducing the sulfur content in various petroleum fractions down to ultra-low values with sufficiently high selectivity . In this case, the reaction products, sulfones, can be selectively recovered and used in various industries and agriculture. , …”

Recent Advances and Challenges in Developing Technological Methods Assisting Oxidative Desulfurization of Liquid Fuels: A Review

“… Using microwave technology to upgrade heavy petroleum into lighter and more valuable products has attracted researchers’ interest in recent years . Microwave heating has been considered in process industries and heavy oil recovery due to the advantages of rapid, volumetric, and selective heating . Because more sulfur-containing compounds in the oil are polar molecules, microwave energy can be absorbed by these compounds, so microwave heating can increase desulfurization efficiency .…”

“…91 Microwave heating has been considered in process industries and heavy oil recovery due to the advantages of rapid, volumetric, and selective heating. 21 Because more sulfur-containing compounds in the oil are polar molecules, microwave energy can be absorbed by these compounds, so microwave heating can increase desulfurization efficiency. 23 Hydrocarbons as the original components of liquid fuels are not polar, and their temperature does not change significantly in the microwave field; therefore, they do not thermally decompose.…”

“…18,19 The oxidative desulfurization process involves chemical reaction between an oxidizing agent and sulfur-containing compounds with/without catalyst at atmospheric pressure and relatively low temperature. 20,21 By using polar solvents or adsorbents, the obtained compounds (sulfones/sulfoxides) can be removed from the fuel.…”