Aquivion–Carbon Composites with Tunable Amphiphilicity for Pickering Interfacial Catalysis

Abstract

A key demand in biomass conversion is how to achieve high reactivity with immiscible reagents with the use of neither cosolvents nor additives. Pickering interfacial catalysis encompassing the design of amphiphilic catalysts behaving concomitantly as emulsifiers offers an elegant solution. In this study, we prepared a systematic series of amphiphilic Aquivion-carbon composites by the hydrothermal carbonization of guar gum with Aquivion perfluorosulfonic superacid. By tuning the Aquivion-carbon composition, materials with tunable hydrophilic-lipophilic properties could be prepared, showing high versatility for conducting biphasic reactions without stirring. In particular, an optimal formulation based on 5:1 Aquivion-carbon could be developed, showing high activity in the transesterification reaction of glyceryl trioleate with methanol at 100 °C with good reusability due to the genesis of stable Pickering emulsions.

Biphasic biocatalysis using a CO2-switchable Pickering emulsion

“…Silica particle surfaces become partially hydrophobic as a result of the formation of a surfactant monolayer on their surfaces exposing hydrophobic chains to water. 28,29 The surface-modified particles can then adsorb to the oil-water interface and stabilize oil drops in water. This in situ hydrophobization of DMA-CO 2 on silica nanoparticles can be further monitored by evaluating the change in the wettability of a negatively charged glass slide (mimic of bare silica particle surface) immersed in solutions of DMA-CO 2 .…”

Multiphase Microreactors Based on Liquid–Liquid and Gas–Liquid Dispersions Stabilized by Colloidal Catalytic Particles

“…. Particle-stabilized L-L microreactors for acid-base catalyzed reactions:a )Acetalization; [63] b) Deacetalization; [64] c) Etherification; [65] D) hydrolysis; [66,67] e) Transesterification; [68][69][70][71] f) Alkylation/acylation; [72,73] g) Pechmannr earrangement. [74] Angewandte Chemie Aufsätze Surface-active catalysts have been developed for biodiesel synthesis by transesterification of vegetable oils with methanol (MeOH) (Figure 2e).…”

“… Particle‐stabilized L‐L microreactors for acid‐base catalyzed reactions: a) Acetalization; [63] b) Deacetalization; [64] c) Etherification; [65] D) hydrolysis; [66, 67] e) Transesterification; [68–71] f) Alkylation/acylation; [72, 73] g) Pechmann rearrangement [74] …”

A Metal-Free Carbon-Based Catalyst: An Overview and Directions for Future Research

“…For instance, doped graphene has been employed as a carbocatalyst for selective hydrocarbon, styrene, and cyclooctane oxidation [72], while N-doped graphene materials have gained substantial attention as catalysts for the hydrochlorination of acetylene [73]. Recently, the best transesterification conversion of glyceryl trioleate was observed using an aquivion-carbon composite as a catalyst in methanol at mild conditions [74]. In another study, carbon blacks act as effective metal-free catalysts for the conversion of olefins to alkanes using a reducing agent, hydrazine [13].…”