Ionic Liquid@Amphiphilic Silica Nanoparticles: Novel Catalysts for Converting Waste Cooking Oil to Biodiesel

Abstract

The conversion of waste cooking oil (WCO) to biodiesel is promising in the green energy and sustainable development sector. In this study, ionic liquid@amphiphilic silica nanoparticles (IASNPs) combining the aspects of amphiphilic Pickering emulsions and acidic ionic liquids (ILs) were developed for green biodiesel production from the transesterification of WCO and methanol. Based on the interesting principle of interfacial catalysis in a Pickering emulsion, this novel catalyst could effectively promote the catalytic reaction occurring at the three-phase interface by constructing water-in-oil microdroplets (with each microdroplet being considered a microreactor) without any surfactant additives, considerably overcoming the disadvantage of limited mass-transfer ability in heterogeneous catalysis. This synergistic effect between the amphiphilic nature and IL acidic catalysis was well optimized during the construction of IASNPs, and the Box−Behnken response surface methodology was used to optimize the operating conditions of biodiesel production. The results showed that an ultrahigh biodiesel yield of 91.45% was obtained under optimum conditions, even without mechanical stirring. Furthermore, there was little loss of biodiesel yield after six cycles via simple centrifugation, validating its ease of recovery, robust catalytic stability, and low cost. Our work provides an important methodology and catalyst design tool for the green and sustainable reutilization of WCO.

Structure and catalytic performance relationship of ionic liquids as recyclable alcoholysis catalysts for green preparation of ethylene‐vinyl alcohol copolymer

“…Recent studies demonstrated that ILs are relatively clean and efficient transesterification catalysts for biofuel production and depolymerization of polyester, 31–38 owing to their unique features of good proton‐donating ability or high electronegativity and selective solubility to macromolecular polymers. For instance, Chen's group used silica‐immobilized sulfonic group‐functionalized ILs to catalyze the transesterification of waste cooking oil and methanol for green biodiesel production, and a high yield of 91.4% was achieved 39 . Singh and coworkers reported that a low‐cost and biocompatible IL, cholinium phosphate ([Ch] 3 [PO 4 ]), effectively catalyzed glycolysis of polyethylene terephthalate (PET) with ~100% conversion and 60.6% yield of bis(2‐hydroxyethyl)terephthalate and could be reused at least three times without an apparent decrease in activity 40 .…”

Competition of Dual Roles of Ionic Liquids during In Situ Transesterification of Wet Algae

“…Ionic liquids (ILs) have been recognized as green solvents of cellulose since 2002 owing to their low melting point, negligible vapor pressure, and high thermostability properties. − Benefiting from the solubilities of cellulose, ILs have been reported to be benign solvents for the dissolution and hydrolysis of wet algae . Consequently, tons of research studies regarding IL-assisted lipid extraction have been conducted for exploring how the structures of ILs affect lipid extraction from microalgae .…”

Fast Assembly of Metal Organic Framework UiO-66 in Acid-Base Tunable Deep Eutectic Solvent for the Acetalization of Benzaldehyde and Methanol

“…Ionic liquids (ILs), as green solvents, are widely used in the synthesis of metal oxides, and MOFs due to their unique properties [ 20 , 21 , 22 , 23 ]. They have many advantages, such as acting as both solvent and structure direction agent with tunable hydrophilic and hydrophobic property, dissolving organic and inorganic precursors, thermal stability, environmental benignity, and so on [ 24 ].…”

“…Recently, they have also reported that aprotic IL 1-hexyl-3-methylimidazolium chloride as solvent could significantly accelerate the room-temperature formation of Zr-based MOFs with the help of acetic acid within only a half hour [ 27 ]. We also previously prepared manganese-based oxides catalysts under the assistance of ILs with efficient catalytic activity for selective oxidation of 5-hydroxymethylfurfural [ 20 , 21 ]. However, ILs with complex preparation procedures, low biodegradability, and high cost have limited their practical applications.…”