• Journal of Integrative Natural Science
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• v.14 no.3
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• pp.99-106
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• 2021

A mixture of alcohol and water is commonly used as antifreeze, liquor, and the fundamental solvents for the manufacture of cosmetics, pharmaceuticals, and inks in our daily life. Since various properties of alcohol water mixtures such as density, boiling or melting point, viscosity, and dielectric constant are determined by their mixing ratio, it is very important to know the mixing ratio to predict their properties. One of simple method to find the mixing ratio is measuring the density of the mixtures. However, it is not easy to predict the mixing ratio from the density of the mixtures because the relationship between mixing ratio and density has not been established well. The relationship is dependent on the relative sizes of solute and solvent molecules, and their interactions. Recently, an empirical model to predict the density of glycerol water mixture from their mixing ratio has been introduced. The suggested model is simple but quite accurate for glycerol water mixture. In this article, we investigated the applicability of this model to different alcohol water mixtures. Densities for six different alcohol water mixtures containing various alcohols (e.g., ethylene glycol, 1,3-propane diol, propylene glycol, methanol, ethanol, and 1-propanol) were simulated and compared to experimentally measured ones to investigate the applicability of the model proposed for glycerol water mixtures to other alcohol water mixtures. The model predicted the actual density of all alcohol water mixtures tested in this article with high accuracy at various ratios. This model can probably be used to predict the mixing ratio of other alcohol water mixtures from their densities beyond 6 alcohols tested in this article from their densities.

• KSBB Journal
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• v.26 no.5
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• pp.471-476
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• 2011

Nowadays biodiesel (fatty acid methyl ester, FAME) has been becoming an important issue as a desired alternative of energy products because of non-toxic, biodegradable properties, and lower exhaust emissions. During esterification of fatty acids or transesterification of oils and fats with short chain alcohols by the alkali-catalyzed methanolysis, FAME and unrefined glycerol are generated. Quantification of glycerol as a by-product is important because of a determinant of biodiesel quality. However, the glycerol analysis by gas chromatography (GC) method has laborious works with sample preparation, long time and cost of sample analysis. Thus, there is a need to analyze glycerol more simply. Herein we demonstrate that the colorimetric assay for glycerol analysis conducted by UV-vis spectrophotometer at the wavelength 617 nm whose peak is maximum intensity of malachite green, resulting in the red-shift occurred proportionally as a function of glycerol amount. Thus, it is considered the solvent media for malachite green fading for biodiesel production: (1) water, (2) MeOH, and (3) EtOH. The resulting findings show that the peak intensity at 617 nm in glycerol-malachite green mixture had a relationship between glycerol concentration and degree of peak shift as increase in pure glycerol concentration approximately at pH 7.0. However, when it was measured the unrefined glycerol concentration by diluting and adjusting with water to buffer (pH 7.0), it was not observed the absorption peak at 617 nm because of impurities and OH ions. In case of glycerol from biodiesel production factories, glycerol concentration could be successfully measured.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.893-900
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• 1997

In this study, vapor-liquid equilibria of a binary system, which consists of glycerol and water, are measured using a vaporrecirculating modified Othmer still at various subatmospheric pressures. The constituent components of the binary system considered in this study exhibit a large difference in the boiling temperatures. Since it is generally observed that the properties of a mixture greatly differ from those of the pure components, the phase equilibrium characteristics of a mixture can not be predicted from the properties of the pure components. Furthermore, an abrupt increase in the boiling temperature occurs as the concentration of the higher boiling component exceeds a certain value. Therefore, it is essential to acquire realistic phase equilibrium data of the mixture for industrial applications. Using the UNIQUAC model, the experimental vapor-liquid equilibrium data are correlated with good accuracy. The thermodynamic consistency test is also performed to ensure soundness of the data.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.727-735
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• 2014

For improved sustainability of the biorefinery industry, biorefinery-byproduct glycerol is being investigated as an alternate source for hydrogen production. This research designs and optimizes a hydrogen-production process for small hydrogen stations using steam reforming of purified glycerol as the main reaction, replacing existing processes relying on steam methane reforming. Modeling, simulation and optimization using a commercial process simulator are performed for the proposed hydrogen production process from glycerol. The mixture of glycerol and steam are used for making syngas in the reforming process. Then hydrogen are produced from carbon monoxide and steam through the water-gas shift reaction. Finally, hydrogen is separated from carbon dioxide using PSA. This study shows higher yield than former U.S. DOE and Linde studies. Economic evaluations are performed for optimal planning of constructing domestic hydrogen energy infrastructure based on the proposed glycerol-based hydrogen station.

• Advances in concrete construction
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• v.10 no.5
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• pp.381-391
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• 2020

This study aimed to develop reference materials (RMs) for mortar that can simulate the initial flow characteristics with constant quality over a long period. Through the previous research on the development of RMs for cement paste, the combination of limestone, glycerol, and water was used as the basic matrix for developing RMs for mortar in this study. In addition, glass beads of three particle sizes (0.5, 1.0, and 2.0 mm) and ISO standard sand were selected as tentative candidates to derive fine aggregate substitutes. The mixture of glass beads could simulate the initial flow characteristics of mortar, but under the same mixing ratio, replicates showed an unstable tendency to indicate inconsistent values due to the generation of electrostatic properties between materials and equipment. On the other hand, the mixture using ISO standard Sand not only simulates the constant flow characteristics for a long period of time, but also shows stable results with little error in replicates. Therefore, limestone, glycerol, ISO standard sand, and water were finally determined as components that met the required properties of RMs for mortar. The effect of each component on the flow characteristics of RMs was analyzed. It was found that glycerol increased the cohesion between the particles of standard sand, resulting in a constant increase both in the plastic viscosity and yield stress. Both limestone and standard sand had a dominant effect on the yield stress. The relationships between various mortar mixing ratios and the corresponding mixing ratios of RMs were established. In addition, the results of the verification experiment showed that the rheological properties of the RMs obtained through the relationships correlated with various water/cement ratios and the fine aggregate volume fractions of mortar obtained with same manner. In other words, the RMs for mortar developed in this study can be used as standard samples because they can simulate the initial flow characteristics of mortar of various mixing ratios for a long period without any chemical changes.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.84-90
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• 2004

Diglyceride (DG) was prepared by reaction of soybean oil and glycerol in the presence of lipase. The initial rate of DG production was greatly affected by the amount of lipase. However the DG content at equilibrium was hardly affected by the amount of lipase added to the reaction mixture. The initial rate of FFA formation was highly affected by the moisture content between 0.5 and 2.3%, but at higher water content (3.3-5.2%), there was a small increase in the rate. And DG content at equilibrium slowly increased with the increase of the water content in glycerol up to 4.4%. However, there was a sharp decrease in DG content at higher water content (5.2-6.4%) due to higher free fatty acid production. The highest yield of DC was obtained at the temperature ranges of 30-5$0^{\circ}C$. The final yield of DG was not dependent on the glycerol (GL) to triglyceride (TG) molar ratio. However, at the molar ratio of 0.75:1 (GL/TG), the enzyme-catalyzed reaction was highly efficient and utilized all the glycerol. In optimized conditions for glycerolysis a yield of approximately 45% DG was obtained. 66% of total DG was 1,3-DG.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1752-1757
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• 2008

Simple and highly efficient droplet merging method is proposed, which enables two nanoliter or picoliter droplets to merge regularly in a straight microchannel. We observe that two droplets of the same size but of different viscosities are merged by velocity difference induced as they are transported with the carrier fluid. To make viscosity difference, the mass ratio of water and glycerol is varied. Two droplets of the same size or of different sizes are generated alternatingly in the cross channel by controlling flowrates. This droplet merging method can be used to mix or encapsulate one target sample with another material, so that it can be applied to cell lysis, particle synthesis, drug discovery, hydrogel-bead production, and so on.

• The Journal of Natural Sciences
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• v.9 no.1
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• pp.83-88
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• 1997

The critical behavior was studied in the mixture of lysozyme and salt water near the phase separation temperature. The 3rd order nonlinear optical susceptibility was measured through the self-induced ellipse rotation. And we obsered that as the quantity of salt and glycerol increase, the phase separation temperature increases and decreases, respectively.

• Korean Journal of Optics and Photonics
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• v.8 no.6
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• pp.461-465
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• 1997

The 3rd order nonlinear optical susceptibility was measured through the self-induced ellipse rotation. The phase separation temperature increases with the increase of salt and it decreases with the increase of glycerol.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.145-150
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• 2022

Dynamic contact angles have investigated by numerous researchers for understanding interfacial behavior at moving contact lines However, due to limitation of visualization techniques, previous experiments for dynamic contact angles have conducted limitedly in hydrophilic capillary tubes based on visible ray. Recently, there is continuous need for research on dynamic contact angles in hydrophobic capillary tubes on various research and industrial fields. Therefore, in this study, we measure the dynamic contact angles of water-glycerol mixture slug in hydrophobic microtubes using synchrotron X-ray imaging. Based on the visualized data, we verified the previous experimental correlations for dynamic contact angles.