Search results for "liquid"

Liquid–Liquid Equilibria of the Water + 1-Propanol + 1-Butyl-1-methylpyrrolidinium Bis(trifluoromethylsulfonyl)imide Ternary System: Study of the Abi…

2016

An important problem in the chemical industry is the separation of azeotropes. Their separation by simple distillation is basically impossible, and extractive distillation consumes much more energy than liquid–liquid extraction, so this alternative could be interesting. Recently, researchers have started to explore these option using ionic liquids as the solvent. The remarkable properties of ionic liquids have made them sustainable alternatives to conventional solvents. This work is a continuation of a study developed by our research group on the use of ionic liquids as extractant solvents of alcohol + water mixtures which form azeotropes, using in this case 1-butyl-1-methylpyrrolidinium bi…

Liquid–Liquid Equilibria of Water + Ethanol + 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide Ternary System: Measurements and Correla…

2015

In this work authors present the experimental liquid–liquid equilibria (LLE) data of water + ethanol + 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([bmim][Tf2N]) system at different temperatures. The LLE of the system was obtained in the temperature range from 283.2 to 323.2 K. The nonrandom two liquid (NRTL) and universal quasichemical (UNIQUAC) models were used to correlate ternary systems. The equilibrium compositions were successfully correlated by the interaction parameters from both models, however UNIQUAC gave a more accurate correlation. Finally, a study about the solvent capability of ionic liquid was made in order to evaluate the possibility of separating the mi…

Isobaric vapor–liquid equilibria for binary and ternary mixtures with cyclohexane, cyclohexene, and morpholine at 100kPa

2010

Abstract Vapor–liquid equilibria (VLE) data at 100 kPa have been determinated for the ternary system cyclohexane + cyclohexene + morpholine and two constituent binary systems cyclohexane + morpholine and cyclohexene + morpholine. The thermodynamic consistency of experimental data has been verified. Both binary systems deviate moderately from ideality without the presence of an azeotrope. The VLE data have been well correlated using local composition models (Wilson, NRTL and UNIQUAC) and have been also predicted with the original UNIFAC.

Isobaric vapor-liquid equilibria for extractive distillation of 1-propanol + water mixture using thiocyanate-based ionic liquids

2017

Abstract This paper presents vapor-liquid equilibrium (VLE) data at 101.3 kPa for the ternary systems 1-propanol + water + 1-ethyl-3-methylimidazolium thiocyanate [emim][SCN] and 1-propanol + water + 1-butyl-3-methylimidazolium thiocyanate [bmim][SCN] and their constituents binary systems. The experimental data obtained were correlated using the NRTL, eNRTL and UNIQUAC models. It was found that the addition of these ionic liquids enhance the relative volatility of 1-propanol to water, and the separation ability follows the order of [emim][SCN] > [bmim][SCN]. The results obtained were compared with the VLE data of the system containing this azeotropic mixtures with different imidazolium-base…

Isobaric vapour–liquid equilibria for binary systems of 2-butanone with ethanol, 1-propanol, and 2-propanol at 20 and 101.3kPa

2008

Abstract Consistent isobaric vapour–liquid equilibrium data have been measured for 2-butanone + ethanol, 2-butanone + 1-propanol, and 2-butanone + 2-propanol at 20 and 101.3 kPa. The binary systems 2-butanone + ethanol and 2-butanone + 2-propanol present a minimum boiling azeotrope at both pressures, and show that the azeotropic compositions is strongly dependent on pressure. The equilibrium data were correlated using the Wilson, NRTL, and UNIQUAC models for which the parameters are reported.

Isobaric vapor–liquid equilibrium for ternary mixtures of ethanol and methylcyclohexane with 3-methylpentane and tert-butyl alcohol at 101.3kPa

2007

Abstract Consistent vapor–liquid equilibrium (VLE) data for the ternary systems 3-methylpentane + ethanol + methylcyclohexane and ethanol + tert-butyl alcohol (TBA) + methylcyclohexane are reported at 101.3 kPa. The VLE data have been correlated by Wilson, UNIQUAC and NRTL equations. The ternary systems do not present azeotrope and are well predicted from binary interaction parameters.

In situ ATR-IR studies in aqueous phase reforming of hydroxyacetone on Pt/ZrO2 and Pt/AlO(OH) catalysts: The role of aldol condensation

2018

Abstract In situ Attenuated Total Reflection Infrared (ATR-IR) spectroscopy was used to study Aqueous Phase Reforming of hydroxyacetone on Pt/AlO(OH) and Pt/ZrO2 catalysts at 230 °C/ 30 bar. Formation of strongly adsorbed aldol condensation products was observed on the surface of Pt/ZrO2 and ZrO2 in contrast to Pt/AlO(OH) and AlO(OH). Peak assignments were supported by DFT calculations of the IR spectra of the condensation products in vacuum and in the presence of water. Aldol condensation of hydroxyacetone leading to compounds with high molecular weight with unsaturated bonds was suggested as a first step in coke formation. Carbonaceous deposits on the surface of the ZrO2 support are oxyge…

Ultrasound-Assisted Extraction, Centrifugation and Ultrafiltration: Multistage Process for Polyphenol Recovery from Purple Sweet Potatoes

2016

This work provides an evaluation of an ultrasound-assisted, combined extraction, centrifugation and ultrafiltration process for the optimal recovery of polyphenols. A purple sweet potato (PSP) extract has been obtained using ultrasonic circulating extraction equipment at a power of 840 W, a frequency of 59 kHz and using water as solvent. Extract ultrafiltration, using polyethersulfone (PES), was carried out for the recovery of polyphenol, protein and anthocyanin. Pre-treatment, via the centrifugation of purple sweet potato extract at 2500 rpm over 6 min, led to better polyphenol recovery, with satisfactory protein removal (reused for future purposes), than PSP extract filtration without cen…

Ultrasounds and ionic liquids assisted methanolysis of polycarbonate: The route towards a more sustainable recycling

An inter-laboratory validation of methods of lipid peroxidation measurement in UVA-treated human plasma samples

2010

Lipid peroxidation products like malondialdehyde, 4-hydroxynonenal and F2-isoprostanes are widely used as markers of oxidative stress in vitro and in vivo. This study reports the results of a multi-laboratory validation study by COST Action B35 to assess inter-laboratory and intra-laboratory variation in the measurement of lipid peroxidation. Human plasma samples were exposed to UVA irradiation at different doses (0, 15 J, 20 J), encoded and shipped to 15 laboratories, where analyses of malondialdehyde, 4-hydroxynonenal and isoprostanes were conducted. The results demonstrate a low within-day-variation and a good correlation of results observed on two different days. However, high coefficie…