Temperature regulated Brønsted acidic ionic liquid-catalyze esterification of oleic acid for biodiesel application

Advances in Enzyme and Ionic Liquid Immobilization for Enhanced in MOFs for Biodiesel Production

Biodiesel is a promising candidate for sustainable and renewable energy and extensive research is being conducted worldwide to optimize its production process. The employed catalyst is an important parameter in biodiesel production. Metal-organic frameworks (MOFs), which are a set of highly porous materials comprising coordinated bonds between metals and organic ligands, have recently been proposed as catalysts. MOFs exhibit high tunability, possess high crystallinity and surface area, and their order can vary from the atomic to the microscale level. However, their catalytic sites are confined inside their porous structure, limiting their accessibility for biodiesel production. Modification of MOF structure by immobilizing enzymes or ionic liquids (ILs) could be a solution to this challenge and can lead to better performance and provide catalytic systems with higher activities. This review compiles the recent advances in catalytic transesterification for biodiesel production using enzymes or ILs. The available literature clearly indicates that MOFs are the most suitable immobilization supports, leading to higher biodiesel production without affecting the catalytic activity while increasing the catalyst stability and reusability in several cycles.

Codoped Phosphotungstate as an Efficient Heterogeneous Catalyst for the Synthesis of n-Butyl Oleate

A quaternary ammonium and titanium codoped phosphotungstate (QA_0.5Ti_0.5H_0.5PW) catalyst was prepared by the ion exchange method and used as a solid acid catalyst for the synthesis of n-butyl oleate. The catalyst was characterized by Fourier transform infrared, elemental analyzer, energy-dispersive X-ray spectrometry, Brunauer-Emmett-Teller, scanning electron microscopy, and Hammett indicator methods. QA_0.5Ti_0.5H_0.5PW showed a higher catalytic activity than other phosphotungstate solid acid catalysts reported by literature, and the esterification rate reached 99% under optimized conditions. Moreover, QA_0.5Ti_0.5H_0.5PW exhibited well reusability. An esterification rate of 90.1% was still obtained in the eighth run.

Catalytic synthesis of chloroacetates with thermoregulated ionic liquids based on vanadium-substituted polyoxometalate

A series of polyoxometalate-based ionic liquid (POM-IL) catalysts with functional sulfonic acid groups, [TEAPS]_3+nPW_12−nV_nO₄₀ (n = 1, 2, 3) were synthesized and characterized by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectrophotometry (FT-IR), UV-Vis spectrophotometry (UV), potentiometric titration and thermogravimetry-differential scanning calorimetry (TG-DSC). The catalytic ability and reusability of the POM-IL catalysts were evaluated on esterification of chloroacetic acid and n-amyl alcohol. The optimum reaction conditions, 0.2 g of the catalyst amount, 10 mL of water carrier, 140 °C of reaction temperature, and 1.2/1 of the molar ratio of alcohol/acid, were obtained by an orthogonal test. [TEAPS]₅PW₁₀V₂O₄₀ was found to be the best active catalyst with an esterification rate of 98.75% and could be reused five times without significant decrease in activity. The ionic liquid acted as a temperature-responsive catalyst, forming a homogeneous mixture with the reactants at reaction temperature, and could be precipitated and separated from products when the reaction ends at ambient temperature. Therefore, an environmentally friendly and highly efficient approach for the synthesis of chloroacetates is provided.

The ionic liquid catalyst [TEAPS]₅PW₁₀V₂O₄₀ exhibited good activity and reusability in the esterification process owing to its acidity and thermoregulated properties.

Heterogenization of a homogenous catalyst: synthesis and characterization of imidazolium ionene/OH−@SiO2 as an efficient basic catalyst for biodiesel production

This study provides a new route for heterogenization of a homogeneous catalyst. The catalyst applied for at least 5 cycles.

Ir/C and Brφnsted acid functionalized ionic liquids: an efficient catalytic system for hydrogenation of nitrobenzene to p-aminophenol

Hydrogenation of nitrobenzene to p-aminophenol using Ir/C and Brφnsted acid functionalized ionic liquids as catalysts.

Brønsted acidic ionic liquid-promoted direct C3-acylation of N-unsubstituted indoles with acid anhydrides under microwave irradiation

A green and efficient method for the synthesis of 3-acylindoles using a Brønsted acidic ionic liquid under microwave irradiation has been developed.