Selection of ionic liquids and deep eutectic solvents via quantum chemical methods and liquid-liquid equilibria involved in the extractive denitrogenation of diesel / Hanee Farzana Hizaddin

The removal of nitrogen compounds from transportation fuel is proven to enhance the efficiency of desulfurization process, which aims to meet the rigorous regulations regarding zero-emissions. Ionic liquids (ILs) and deep eutectic solvents (DESs) were screened for this purpose using quantum chemical methods. Geometry optimization was performed for all involved species at Hartree-Fock level and 6-31G* basis set. Generation of cosmo files using Density Functional Theory and Triple zeta valence potential basis set was carried out at single point calculation. The cosmo files were used to obtain σ-profiles and σ-potentials for qualitative screening of ILs and DESs. (i) The screening of ILs revealed that cations with an aromatic ring have better capacity as hydrogen bond donors (HBDs) than do non-aromatic cations, whereas the acetate anion appeared to have better affinity towards HBD than did ethylsulfate and methanesulfonate anions. The σ-profile and σ-potential analysis confirmed that there is an interaction between nitrogen compounds and cations via CH-π interaction along with between nitrogen compounds and anions via hydrogen bonding. Moreover, a detailed quantum chemical calculation was performed to investigate the interaction between ILs and nitrogen compounds at molecular level, in which optimized geometry was used to obtain the orbital energies, global scalar properties, interaction energies and partial charges. The calculations indicated that cations with an aromatic ring, that is, imidazolium and pyridinium, combined with either ethylsulfate or methanesulfonate anion have favorable interaction with nitrogen compounds in comparison to cations without an aromatic ring. (ii) The screening of DESs showed that the interaction between nitrogen compounds and DESs is based on hydrogen bonding. Altogether, 94 DESs were examined quantitatively by predicting the values of the activity coefficients at infinite dilution of nitrogen compounds and diesel in the DESs. These were then used to estimate selectivity, capacity and iv performance index at infinite dilution as the basis of the screening process taking into account the cation, anion and HBD choices as well as the salt:HBD molar ratio. Based on the screening results, 22 ternary liquid-liquid equilibria (LLE) experiments were carried out at room temperature and atmospheric pressure to test three ILs – namely 1-ethyl-3-methylimidazolium ethylsulfate, 1-ethyl-3-methylpyridinium ethylsulfate, and 1-ethyl-3-methylimidazolium methanesulfonate, and two DESs – namely tetrabutylammonium bromide/ethylene glycol (1:2) and tetrabutylphosphonium bromide/ethylene glycol (1:2). The aim was to remove non-basic and basic nitrogen compounds from n-hexadecane as a model diesel compound. NMR spectroscopy was used for the compositional analysis. Consistency tests were performed to ascertain the reliability of all experimental data. All ternary systems reported distribution ratios and selectivity values greater than unity with minimal cross-contamination between the extract and raffinate phases. The ternary LLE data were correlated with NRTL model and compared with COSMO-RS predictions, both of which were in excellent agreement with the experimental tie-lines. In conclusion, the quantum chemical screening of ILs and DESs explained the interaction between ILs/DESs and nitrogen compounds at molecular level, which facilitates solvent selection for the denitrogenation process. The ternary LLE experiments with the selected ILs and DESs confirmed that these solvents have high potential for industrial extractive denitrogenation

Extraction of nitrogen compounds from model fuel using 1-ethyl-3-methylimidazolium methanesulfonate

Removal of nitrogen compounds is an essential process in the fuel processing industry. In this work, the extraction performance of 1-ethyl-3-methylimidazolium methanesulfonate ([Emim][MeSO3]) ionic liquid in removing pyrrole, indoline, pyridine and quinoline from cyclohexane is investigated. The ternary liquid-liquid equilibria for four systems containing [Emim][MeSO3] + pyrrole/indoline/pyridine/quinoline + cyclohexane were predicted using COSMO-RS and validated experimentally at 298.15 K under atmospheric pressure, with feed concentrations of nitrogen compounds ranging from 5 to 50 wt%. Othmer-Tobias and Hand correlations confirmed the consistency of the experimental data. The tie-lines obtained experimentally and predicted with COSMO-RS were in good agreement. Additionally, the non-random two-liquid (NRTL) model was successfully employed to correlate the experimental tie-lines. The effects of basicity of nitrogen compounds toward extraction efficiency were also investigated. The selectivity and distribution ratio results demonstrated the suitability of [Emim][MeSO3] as an extraction solvent for removing nitrogen compounds from fuel. Finally, the multicomponent extraction confirmed the performance of [Emim][MeSO3] for extractive denitrogenation. In all ternary systems investigated in this work, the concentration of cyclohexane in the extract phase was very small and the presence of the IL in the raffinate phase was negligible indicating minimum cross contamination between the extract and raffinate phases

Liquid-liquid equilibria data for the separation of ethylbenzene/styrene mixtures using ammonium-based deep eutectic solvents

Separation of styrene from ethylbenzene is challenging because of their close boiling points and similar chemical characteristics. In this study, we utilized three ammonium-based deep eutectic solvents (DESs) with glycols as hydrogen bond donors to separate styrene from ethylbenzene via liquid-liquid extraction at room temperature and atmospheric pressure, with styrene concentration in the feed mixture ranging from (10 to 80) wt%. Consistency of the experimental data was ascertained by Othmer-Tobias and Hand correlations, and the NRTL binary interaction parameters were also validated for thermodynamic consistency. Distribution ratios of styrene were found to be comparable to that obtained using ionic liquids, although the selectivity values were much lower. The ternary liquid-liquid equilibria for the systems {ethylbenzene (1) + styrene (2) + DES (3)} were correlated with the NRTL model and predicted using the COSMO-RS approach. The average RMSD from the experimental data for NRTL correlation is 1.41% and for COSMO-RS prediction is 4.74%. © 2019 Elsevier Lt

Analysis of Ternary LLE Data on Increasing Limonene Solubility in Water using Alcohol as Cosolvent

The essential oil (EO) quality can be enhanced by increasing the concentration of oxygenated compounds. This can be achieved by extracting terpenes from the oil. As terpenes are insoluble in water, alcohols are often added to increase the solubility. It is important to find a suitable co-solvent to increase the efficiency of terpene extraction using water; this can be indicated by the miscibility (one phase) region in the water–cosolvent–terpene ternary diagram. In this work, three alcohols, i.e., methanol, ethanol and propanol, were selected as the cosolvents. The mutual solubility of water– methanol/ethanol/propanol–limonene is analysed through the phase equilibria generated from literature data and predicted by the Conductor-like Screening Model (COSMO-RS) programme. COSMO-RS was able to generate accurate LLE data at equilibrium based on the reported experimental feed compositions. The extraction efficiency of using an alcohol increased following the order of methanol<ethanol<propanol according to the increment of the respective miscibility region. At equilibrium, the composition of alcohol is higher in the aqueous phase than that in the organic phase, indicating the affinity of alcohol towards water and the suitability of using alcohol as the co-solvent. As observed, in methanol, its small methyl group increased its solubility in water, but reduce the methanol solubility in limonene (terpene), thus reducing also the miscibility region. Propanol was found to be the most suitable alcohol, and this encourages us for further studies to find other green cosolvents

Enhanced large-scale production of recombinant phytase in E. coli DH5 α: Medium components optimization and thermodynamic studies

Medium components and their solubility for improvement of recombinant phytase production in Escherichia coli DH5α. was optimized and reported in this study. Solubility study was supported by the computational works conducted using COSMO-RS, a quick tool to predict the thermophysical and chemical properties of fluid mixture. Solubility concept through thermodynamic calculation was introduced to study the interaction between medium components with water and selected medium components with each other. Based on the σ-profile and σ-potential, together with Gibbs free energy, a less soluble medium component showed a negative effect on phytase production due to the formation of insoluble metal-ion phytate complexes. Highest phytase production was obtained under optimum conditions of as 30 g/L yeast extracts, 1 g/L (NH4)2HPO4, 3 g/L MgSO4·7H2O, 0.3 g/L FeSO4·7H2O and 0.1 % (v/v) glycerol. Both experimental and computational works were conducted to investigate the interaction between medium components. The melting point and phase appearance of the mixture were studied. From experimental results, the mixtures were seemed to be unstable due to its higher melting point compared to individual medium components. The analysis from Gibbs free energy reflected the total immiscibility between medium components. It was concluded that medium components worked individually to promote the phytase production. Yeast extract, MgSO4·7H2O and FeSO4·7H2O were selected for optimization by central composite design, whereas other factors were maintained at their optimal level. Statistical analysis showed that the optimum media containing 34.06 g/L yeast extract, 3.6 g/L MgSO4·7H2O and 0.32 g/L FeSO4·7H2O gave the maximum phytase production of 118.91 U/mL. The optimization of process condition such as temperature, agitation speed and seed age were further investigated by employing Full Factorial Experimental (FUFE) Design after fixing the media composition. The maximum phytase production of 200 U/mL was obtained at optimum condition (temperature 37 °C, agitation speed 500 rpm and seed age 1.55 at OD600nm). The phytase production in a larger scale was conducted by submerged fermentation in 2 L and 30 L bioreactor. In large scale production, constant tip speed suited the best for scale-up strategy comparing to the constant power number. The optimum process condition improved the phytase production and plasmid stability

Proceedings of International Technical Postgraduate Conference 2022

This conference proceedings contains articles on the various research ideas of the academic &amp; research communities presented at the International Technical Postgraduate Conference 2022 (TECH POST 2022) that was held at Universiti Malaya, Kuala Lumpur, Malaysia on 24-25 September 2022. TECH POST 2022 was organized by the Faculty of Engineering, Universiti Malaya. The theme of the conference is “Embracing Innovative Engineering Technologies Towards a Sustainable Future”.  TECH POST 2022 conference is intended to foster the dissemination of state-of-the-art research from five main disciplines of Engineering: Electrical Engineering, Biomedical Engineering, Civil Engineering, Mechanical Engineering, and Chemical Engineering. The objectives of TECH POST 2022 are to bring together innovative researchers from all engineering disciplines to a common forum, promote R&amp;D activities in Engineering, and promote the dissemination of scientific knowledge and research know-how between researchers, engineers, and students. Conference Title: International Technical Postgraduate Conference 2022Conference Acronym: TECH POST 2022Conference Date: 24-25 September 2022Conference Location: Faculty of Engineering, Universiti Malaya, Kuala Lumpur Malaysia (Hybrid Mode)Conference Organizers: Faculty of Engineering, Universiti Malaya, Kuala Lumpur, Malaysia