Isobaric vapor-liquid equilibriums for the systems glycerol-water and glycerol-water saturated with sodium chloride

Chen, David H. T.; Thompson, A. Ralph

doi:10.1021/je60047a019

Cited by 33 publications

(18 citation statements)

References 4 publications

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“…Plots of evaporation versus time in vacuum for FeCl 3 glycerol solutions are provided in the Supporting Information (Figure S2). These results are consistent with previous studies showing that the vapor pressure of glycerol solutions are salt concentration dependent. , …”

Section: Methodssupporting

confidence: 94%

Iron(III) Speciation Observed at Aqueous and Glycerol Surfaces: Vibrational Sum Frequency and X-ray

Husek

Biswas

et al. 2019

J. Am. Chem. Soc.

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Aqueous solutions of FeCl3 have been widely studied to shed light on a number of processes from dissolution, mineralization, biology, electrocatalysis, corrosion, to microbial biomineralization. Yet there are little to no molecular level studies of the air–liquid FeCl3 interface. Here, both aqueous and glycerol FeCl3 solution surfaces are investigated with polarized vibrational sum frequency generation (SFG) spectroscopy. We also present the first ever extreme ultraviolet reflection–absorption (XUV-RA) spectroscopy measurements of solvated ions and complexes at a solution interface, and observe with both X-ray photoelectron spectroscopy (XPS) and XUV-RA the existence of Fe(III) at the surface and in the near surface regions of glycerol FeCl3 solutions, where glycerol is used as a high vacuum compatible proxy for water. XPS showed Cl– and Fe(III) species with significant Fe(III) interfacial enrichment. In aqueous solutions, an electrical double layer (EDL) of Cl– and Fe(III) species at 0.5 m FeCl3 concentration is observed as evidenced from an enhancement of molecular ordering of water dipoles, consistent with the observed behavior at the glycerol surface. At higher concentrations in water, the EDL appears to be substantially repressed, indicative of further Fe(III) complex enrichment and dominance of a centrosymmetric Fe(III) species that is surface active. In addition, a significant vibrational red-shift of the dangling OH from the water molecules that straddle the air–water interface reveals that the second solvation shell of the surface active Fe(III) complex permeates the topmost layer of the aqueous interface.

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Section: Methodssupporting

confidence: 94%

Iron(III) Speciation Observed at Aqueous and Glycerol Surfaces: Vibrational Sum Frequency and X-ray

Husek

Biswas

et al. 2019

J. Am. Chem. Soc.

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“…Literature data are available for some of the substances investigated, albeit at different temperatures. The vapour pressure of tetraglyme was investigated at temperatures above 100 • C. 23 and above 150 • C. 26 Extrapolation of the respective equations to the experimental temperature of 95 • C results in vapour pressures of 87 Pa and 190 Pa, respectively, compared to the value of circa 60 Pa obtained in this study. While the vapour pressure obtained in this way from the data in Kuczynski et al, 21 190 Pa, is significantly higher than the value obtained in this study, the value of 87 Pa calculated from Chaudhari et al 20 is in fair agreement with the result of this study.…”

Section: Vapour Pressures Of Molecular Solventsmentioning

confidence: 67%

“…In the presence of water, vapour pressure is expected to be higher than for the pure substance. 26 As most of the substances in this study are hygroscopic, this might apply to almost all the experimental data. This is a particularly important aspect for the reference substance glycerol, as any error in the reference experiment will result in errors in all the other calculated vapour pressures.…”

Section: Vapour Pressures Of Molecular Solventsmentioning

confidence: 92%

Measurement of vapour pressures of ionic liquids and other low vapour pressure solvents

et al. 2009

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“…Figure 10 gives the variation of concentration of water (wt%) in the feed with the concentration of water (wt%) in the feed for various membranes at 30°C. These data are compared with VLE data (14). The PV of glyc-erine-water mixture yielded superior separation to that of distillation, particularly for glycerine concentration >90 wt%.…”

Section: °Cmentioning

confidence: 99%

Dehydration of glycerine‐water mixtures by pervaporation

Burshe

Sawant

Pangarkar

1999

J Americ Oil Chem Soc

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Dehydration of glycerine-water mixtures by pervaporation (PV) was studied with Nafion  (NA), cellulose triacetate (CA), polyimide, carboxylated polyvinyl chloride (CPVC), and polyethersulfone (PES) membranes. PES membrane yielded the highest selectivity (6580) and CPVC membrane yielded the lowest selectivity (1552) at 5% by weight of water in the feed and 30°C. The NA membrane yielded the highest permeation flux (0.2-1.45 kg/m 2 h) of water over the entire water concentration range. Energy of activation of permeation for water was in the range of 7-15 kJ/mol, being highest for CPVC and lowest for CA. Comparison of PV and vapor liquid equilibrium data showed that the former gave better results, particularly for concentrating glycerine above 90 wt%.Pervaporation (PV) is a membrane-based separation process suitable for separating liquid mixtures comprising azeotropes and close boiling and temperature-sensitive products (1-3). Extensive research has been carried out to separate ethanol-water mixtures by PV. Apart from ethanol-water mixtures, work dealing with various applications was also published to explore the potential of PV (4-6). Because of its high selectivity and low energy requirements, PV is an alternative separation method in the chemicals industry.Glycerine is used in various products as a solvent, humectant, plasticizer, emollient, sweetener, a fermentation nutrient in the production of antibiotics, antifreeze in automobiles, etc. In the fat-splitting process glycerine is a co-product of soap manufacture and the manufacture of fatty acids (7). Removal of water from crude glycerine is an important step in the production of pure glycerine by the fat-splitting process. Presently, water is removed by evaporation/distillation. The high boiling point of glycerine (290°C), along with its relatively low decomposition temperature (190°C), necessitates the use of vacuum to lower the temperature requirements. For instance, at 10 mm Hg absolute the boiling point of glycerine is 166°C. Even this option cannot prevent the degradation and polymerization of glycerine (7). PV, which can achieve dehydration at much lower temperature, is therefore an attractive alternative.In the present work, attempts were made to use PV for dehydrating aqueous glycerine as a convenient and energy-efficient technique. Various polymeric membranes were prepared and tested for pervaporation of glycerine-water mixtures. PV performance was evaluated in terms of selectivity and flux. The effects of functional groups of the polymer comprising membrane, feed concentration, and feed temperature on the flux and selectivity were studied. Here, selectivity is defined as follows:where α = selectivity (dimensionless), X A = concentration in the feed (wt%) with water, and Y B = concentration in the permeate (wt%) with glycerine. Overall performance of the membrane was evaluated in terms of pervaporation separation index (PSI), defined by Huang (8) as given below:where C pwater and C fwater are water concentrations in the permeate and feed, respectively...

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Isobaric vapor-liquid equilibriums for the systems glycerol-water and glycerol-water saturated with sodium chloride

Cited by 33 publications

References 4 publications

Iron(III) Speciation Observed at Aqueous and Glycerol Surfaces: Vibrational Sum Frequency and X-ray

Iron(III) Speciation Observed at Aqueous and Glycerol Surfaces: Vibrational Sum Frequency and X-ray

Measurement of vapour pressures of ionic liquids and other low vapour pressure solvents

Dehydration of glycerine‐water mixtures by pervaporation

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