Cecilia Devi Wilfred

Dissolution and Delignification of Bamboo Biomass Using Amino Acid-Based Ionic Liquid

In the present work, the dissolution of bamboo biomass was tested using a number of ionic liquids synthesized in laboratory. It was observed that one of the synthesized amino acid-based ionic liquids, namely 1-ethyl-3-methylimidazolium glycinate, was capable of dissolving the biomass completely. The dissolved biomass was then regenerated using a reconstitute solvent (acetone/water) and was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results were compared to preconditioned bamboo biomass. The regenerated biomass was found to have a more homogenous macrostructure, which indicates that the crystalline form and structure of its cellulose has changed from type Ι to type ΙΙ during the dissolution and regeneration process.

Effect of sulfonate-based anions on the physicochemical properties of 1-alkyl-3-propanenitrile imidazolium ionic liquids

In this paper, the physicochemical properties of a new series of ionic liquids (ILs) based on nitrile-functionalised imidazolium cations ([C2CN Cnim]+) with sulfonate-based anions were studied. The ILs were prepared by reacting imidazole with acrylonitrile, followed by butyl- and decyl bromide. The anions of the resulting bromide salts exchanged by metathesis to dioctylsulfosuccinate (DOSS), dodecylsulfate (DDS), benzenesulfonate (BS) and trifluoromethanesulfonate (TFMS). The densities of these ILs are lower compared to the those of other reported nitrile-functionalised ILs, while on the other hand, the viscosities of the ILs are higher due to the effects of the large anions and the long alkyl chain of the cations.

A new approach of probe sonication assisted ionic liquid conversion of glucose, cellulose and biomass into 5-hydroxymethylfurfural

5-Hydroxymethylfurfural (HMF) has been identified as a promising biomass-derived platform chemical. In this study, one pot production of HMF was studied in ionic liquid (IL) under probe sonication technique. Compared with the conventional heating technique, the use of probe ultrasonic irradiation reduced the reaction time from hours to minutes. Glucose, cellulose and local bamboo, treated with ultrasonic, produced HMF in the yields of 43%, 31% and 13% respectively, within less than 10min. The influence of various parameters such as acoustic power, reaction time, catalysts and glucose loading were studied. About 40% HMF yield at glucose conversion above 90% could be obtained with 2% of catalyst in 3min. Negligible amount of soluble by-product was detected, and humin formation could be controlled by adjusting the different process parameters. Upon extraction of HMF, the mixture of ionic liquid and catalyst could be reused and exhibited no significant reduction of HMF yield over five successive runs. The purity of regenerated [C4C1im]Cl and HMF was confirmed by NMR spectroscopy, indicating neither changes in the chemical structure nor presence of any major contaminants during the conversion under ultrasonic treatment. 13C NMR suggests that [C4C1im]Cl/CrCl3 catalyses mutarotation of α-glucopyranose to β-glucopyranose leading to isomerization and finally conversion to HMF. The experimental results demonstrate that the use of probe sonication technique for conversion to HMF provides a positive process benefit.

Synthesis, characterization and thermal properties of thiosalicylate ionic liquids

AbstractIn an attempt to produce new functionalized ionic liquids, a series of thiosalicylate ionic liquids based on imidazolium, ammonium, phosphonium, choline and pyrrolidinium cations were synthesized. The compounds were characterized by Infra Red (IR), Nuclear Magnetic Resonance (NMR) and mass spectra (ESI-MS). Their glass-transition temperatures, melting points and decomposition temperatures have been measured. Physicochemical properties of ionic liquids are influenced by alkyl chain length and nature of the cation of ionic liquids. Graphical AbstractA series of thiosalicylate ionic liquids based on imidazolium, ammonium, phosphonium, choline and pyrrolidinium cations were prepared. The compounds were characterized and their thermal properties were investigated. The physicochemical properties of ionic liquids are influenced by the alkyl chain length and the nature of the cation of ionic liquids.

Densities, viscosities and refractive indices of 1-alkyl-3-propanenitrile imidazolium chloride ionic liquids

In this study, a series of nitrile-functionalised imidazolium ionic liquids ([C2CN Rim]Cl, where R = butyl, hexyl and octyl) were synthesised by reacting imidazole with acrylonitrile and then with butyl, hexyl and octyl chlorides, respectively. The structure of these compounds were established using 1H NMR, FT-IR and elemental analyses. The densities and viscosities were measured at T = (293.15–353.15 K), whereas the refractive index was measured at T = (293.15–333.15 K) and empirical correlations were proposed to represent this study. The decomposition temperatures were determined using a thermogravimetric analyser. The thermal expansion coefficients were also calculated and reported.

Recent Advances and Thermophysical Properties of Acetate-based ProticIonic Liquids

Protic Ionic Liquids (PILs), a substantial branch of the infamous Ionic Liquids (ILs) have gained much attention in recent years. They have been the “go-to” solvent of choice in many areas such as chromatography, catalysis, fuel cells, biological applications etc., due to their thermophysical properties and their ability to be tunable based on task specificity. This review covers two parts, namely; a brief description on the thermophysical properties of acetate PILs (density, speed of sound, viscosity and decomposition temperature) and its current applications in the industry. The collation of the physicochemical data consents structure-property trends would be discussed, and these can be used as a foundation for the development of new PILs to achieve specific properties. Economically, PILs have been suggested as “greener” alternatives to conventional solvents in various industrial applications hence, in order to assess their suitability for such purposes, a thorough evaluation of their mutagenicity, toxicity and carcinogenicity is crucial.

Oxidative Desulfurization of Fuels using 1-Butyl-6-Methyl-Quinolinium Dicyanamide

Deep desulfurization of fuels has attracted a lot of attention from researchers due to more stringent regulations imposed on sulfur content. There is a great demand to comply the regulation in current technology because it requires high pressure, high temperature, and high hydrogen consumption. Furthermore, aromatic sulfur compounds are also inefficient to be removed in current technology. Ionic Liquids (ILs), a class of green solvent plays an important role as a promising alternative for desulfurization of fuels. This study investigates the potential of oxidative desulfurization through liquid-liquid extraction process and the effect of parameter variation towards the efficiency.

Desulfurization of Fuel Using Ionic Liquids: Computational Selection of Cation and Anion

Selection of potential ionic liquid (IL) is carried out in this work using COSMO-RS by analyzing the interaction between dibenzothiophene (DBT) and IL in dodecane. Sigma profile, capacity and selectivity at infinite dilution were used to predict the suitable ILs in desulfurization. Result shows that increasing alkyl length and incorporating nitrile group will increase the capacity and selectivity respectively. 1-butyl-6-methylquinolonium [C4mquin]+, 1-butyl-3-methylimidazolium [Bmim]+, thiocyanate [SCN]- and dicyanamide [N(CN)2]- are potentially good cations and anions.

Desulfurization of oxidized diesel using ionic liquids

The extraction of oxidized sulfur compounds from diesel were carried out using ten types of ionic liquids consisting of different cation and anion i.e. 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazoium thiocyanate, 1-butyl-3-methylimidazoium dicyanamide, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazoliumhexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, trioctylmethylammonium chloride, 1-propionitrile-3-butylimidazolium thiocyanate, 1-propionitrile-3-butylimidazolium dicyanamide and 1-butyl-6-methylquinolinium dicyanamide. The oxidation of diesel was successfully done using phosphotungstic acid as the catalyst, hydrogen peroxide (H2O2) as the oxidant and trioctylmethylammonium chloride as the phase transfer agent. The oxidation of diesel changes the sulfur compounds into sulfone which increases its polarity and enhances the ionic liquids extraction performance. Result showed that ionic liquid [C4mquin][N(CN)2] performed the ...

Integrated Mg/TiO2-ionic liquid system for deep desulfurization

A series of Mg/TiO2 photocatalysts were prepared using wet impregnation method followed by calcination at 300, 400 and 500°C for 1 h. The photocatalysts were characterized using Thermal Gravimetric Analysis, Fourier-Transform Infrared Spectroscopy, X-Ray Diffraction, and Field Emission Scanning Electron Microscopy. The performance for deep desulfurization was investigated using model oil with 100 ppm sulfur (in the form of dibenzothiophene). The integrated system involves photocatalytic oxidation followed by ionic liquid-extraction processes. The best performing photocatalyst was 0.25wt% Mg loaded on titania calcined at 400°C (0.25Mg400), giving 98.5% conversion of dibenzothiophene to dibenzothiophene sulfone. The highest extraction efficiency of 97.8% was displayed by 1,2-diethylimidazolium diethylphosphate. The overall total sulfur removal was 96.3%.