Dilute Alcohol Research Articles

Anion bridges drive salting out of a simple amphiphile from aqueous solution.

Neutron diffraction with isotope substitution has been used to determine the structural changes that occur on the addition of a simple salting-out agent to a dilute aqueous alcohol solution. The striking results obtained demonstrate a relatively simple process occurs in which interamphiphile anionic salt bridges are formed between the polar groups of the alcohol molecules. These ion bridges drive an increase in the exposure of the alcohol molecule nonpolar surface to the solvent water and hence point the way to their eventual salting out by the hydrophobic effect.

Characterization of Tocopherols by Inverse Chromatographic Data

Specific retention volumes (V g 0 ) and fugacity coefficients at infinite dilution (Φ V ∞) of alkanes, alkenes, aromatics, cycloalkanes, n-chloroalkanes, alcohols, ketones, nitriles, and carbon dioxide on four stationary phases were determined by inverse gas chromatography. The stationary phases employed were α-tocopherol, δ-tocopherol, γ-tocopherol, and α-tocopherol acetate. The investigation was carried out at temperatures ranging from 333.15 to 413.15 K. These results have been used to characterize tocopherols in terms of dipolarity/polarizability, hydrogen-bond basicity/acidity, and lipophilicity by means of the equation of solvation proposed by Abraham. The infinite dilution fugacity coefficients have been used for the prediction of the thermodynamic behavior of tocopherols in methanol and carbon dioxide at high pressure.

Effect of mechanical vs dilute ethanol epithelial removal on keratocyte apoptosis and polymorphonuclear leukocyte migration.

To investigate keratocyte apoptosis and polymorphonuclear (PMN) cell infiltration to the corneal stroma after mechanical epithelial scraping and chemical de-epithelialization with 18% ethanol solution. Twelve New Zealand Albino rabbits (24 eyes) were randomly divided into three groups. Group A was the control group with no epithelial removal. Group B underwent a 7.5-mm mechanical epithelial removal with a blunt spatula. Group C underwent 7.5-mm chemical de-epithelialization with 18% ethanol-balanced salt solution. Corneas were stained with terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling (TUNEL) assay after 24 h. Only nuclear staining in keratocytes was counted. Polymorphonuclear (PMN) leukocyte densities were also assessed by light microscopy. Mechanical de-epithelialization (group B) and chemical de-epithelialization with 18% ethanol (group C) showed no difference in keratocyte apoptosis compared with the control group. There was also no difference between groups B and C. Group B showed no difference in PMN leukocyte counts compared with the control group. But the number of PMN leukocytes observed in group C was significantly higher than those encountered in the corneas of the control group (P < 0.05) and group B (P < 0.05). Dilute alcohol induces more PMN cell infiltration when compared with mechanical de-epithelialization although there is no difference in the apoptosis rates.

Thermodynamic analysis of a beer engine

This paper shows how the heat reclaimed from the exhaust gas of a gas turbine engine can be used to convert dilute ethyl alcohol (“beer”) to a fuel that can used to power the engine. Ordinarily, there is not enough heat available to distil the weak liquor to sufficient amounts of a strong product (>90%), due to high exergy destruction. In this design, a combination of destructive distillation and ordinary distillation is used, the wet product then being sent to a reformer for an endothermic shift reaction. The high temperature gas is now ready to burn in a gas turbine engine (or high temperature fuel cell). Water in the low temperature stack gas can be reclaimed in a cooling tower, if desired, so as to have no net loss of water for the system. The exergetic (Second Law) efficiency for power production is nearly 50%.

Solubilization of alcohols in SDS and TTAB from isentropic partial molar compressibilities and solubilities

Partition coefficients of some medium chain alcohols between water and micelles have been determined at infinite alcohol dilution from measured isentropic partial molar compressibilities, at intermediate alcohol concentrations by NMR self-diffusion measurements and at the phase boundary from total solubilities. The surfactants studied were sodium dodecyl sulfate (SDS) and tetradecyltrimethylammonium bromide (TTAB). The agreement between the different methods of measurement is poor. Inspection of the data show, however, that the fraction of alcohol solubilized is constant with respect to alcohol concentration at constant surfactant concentration, and this means that the partition coefficient must be dependent on the alcohol concentration. The partial molar volumes and compressibilities of the alcohols in the solubilized state have been evaluated at infinite dilution, showing increased volumes and compressibilities compared to the aqueous state, as is normal for alcohols in non-aquoeus environments. As alcohol is added at constant surfactant concentration, a significant increase in the partial molar compressibility is observed above a certain alcohol concentration. This happens when the alcohol to surfactant ratio is in the region of 1.7–2.0. The increased compressibility suggests that the alcohol molecules, on average, experience a more hydrophobic environment. A reasonable interpretation is that some of the solubilized alcohol molecules will be solubilized in the micellar interior, once the alcohol to surfactant ratio exceeds a critical value.

A Magnetic Resonance Study of Complex Formation between the Neutral Phenalenyl Radical and Alkali Metal Ions in Dilute Alcohol Solutions

In previous work from our laboratories we have characterized the molecular motion of phenalenyl in the supercage of cation-exchanged X- and Y-zeolites using continuous wave−electron paramagnetic resonance (CW-EPR) and pulsed-EPR techniques. The trends in activation energies with cation size and Lewis acidity and in EPR line widths provided circumstantial evidence for a weak covalent interaction between the neutral phenalenyl π-system and the cations. This work on phenalenyl and alkali metal cations in solution provides 7Li nuclear magnetic resonance (NMR) and CW-EPR spectroscopic evidence for this type of interaction. Moreover, to our knowledge it is the first example of a neutral radical−alkali metal ion complex in solution. In rigorously dried alcohol solutions this interaction results in the formation of a complex between neutral phenalenyl and Li+ or Na+, which is in equilibrium with solvated phenalenyl and the respective cation. The forward and reverse rates for this equilibrium for Li+ and phenaleny...

Equilibrium data on ethanol-water-solvent ternaries

Experimental liquid-liquid equilibria of water-ethanol-1-nonanol and water-ethanol-1-decanol systems were investigated at 303.16± 0.20 K. The reliability of the experimental tie-line data was ascertained by using Othmer-Tobias and Hand plots. Distribution coefficients (Di) and separation factors (S) were evaluated for the immiscibility region. It is concluded that the solvents with high boiling point, 1-nonanol and 1-decanol, are suitable separating agents for dilute aqueous ethyl alcohol solutions.

Efficacy of a potentized homoeopathic drug (Arsenicum-Album-30) in reducing cytotoxic effects produced by arsenic trioxide in mice: III. Enzymatic changes and recovery of tissue damage in liver

Objective: To determine whether the potentized homoeopathic drug Arsenicum Album-30 can induce enzymatic and some other biochemical changes to repair tissue damage caused by the injection of arsenic trioxide in mice. Design: Controlled laboratory study. Methods: Mice injected with arsenic trioxide and then orally administered the homoeopathic drug were compared with control animals who either received saline only, or injections of arsenic trioxide, or injections of arsenic trioxide followed by orally administered dilute alcohol. Activities of the enzymes acid and alkaline phosphatases, lipid peroxidation and reduced glutathione, which are used as ‘marker’ enzymes for cytotoxicity levels, were assessed by standard methods. Histopathological slide preparations of liver were made by routine microtechnique method of tissue sectioning and staining with haematoxylin- eosin for histological examination. Results: The mice fed homoeopathic drug showed positive results of tissue recovery both in terms of enzymatic and histological changes, compared to controls. Conclusions: The homoeopathic drug is capable of preventing or repairing liver damage induced by arsenic trioxide and the positive changes were also confirmed by the activities of the enzymatic markers.

A Calorimetric Investigation of the Interaction of Short Chain Alcohols with Unilamellar DMPC Liposomes

The molecular mechanisms by which ethanol and other short-chain alcohols perturb biological systems have been suggested to involve specific interactions with proteins and/or nonspecific interactions with the lipid bilayer part of biological membranes. To gain insight into the influence of alcohols on well-defined lipid bilayers, isothermal titration calorimetry (ITC) is used to determine the excess partial molar enthalpy of alcohol in liposome suspensions as well as the excess partial molar enthalpy of liposomes in dilute alcohol−water mixtures at temperatures above the main phase transition of dimyristoyl phosphatidylcholine (DMPC). The alcohols investigated were ethanol, 1-propanol, and 1-butanol. The calorimetric data were used to evaluate molecular interactions and based on a simple partitioning model the standard molar enthalpy of transferring alcohol from water into unilamellar DMPC liposomes was determined. The results reveal that the interaction of short-chain alcohols with the DMPC lipid bilayer ...

Self-association and complex formation in alcohol-unsaturated hydrocarbon systems Heat capacities of linear alcohols mixed with alkenes and alkynes

Apparent molar heat capacities, Cmapp, at dilute alcohol concentrations and excess molar heat capacities, CpE throughout the concentration range were determined at 25°C for the following systems: methanol, ethanol, propan-1-ol, hexan-1-ol and decan-1-ol mixed with n-octane, oct-1-ene and oct-1-yne; in addition, the following mixtures were also measured: hexan-1-ol with oct-4-yne, cyclohexane, cyclohexene, benzene, hex-1-ene, dec-1-ene and an equimolar mixture of n-octane+oct-1-yne. The experimental Cmapp show a maximum against alcohol concentration; this maximum is reduced in magnitude and displaced to higher alcohol concentrations when the inert n-octane is substituted by the unsaturated oct-1-ene, oct-1-yne, oct-4-yne, cyclohexene or benzene which act as weak proton acceptors, forming complexes or cross-associated species with the alcohol molecules. The present data clearly indicate that there are alcohol–alkene complexes in solution, which are weaker than the alcohol–alkyne ones, but detectable through heat capacity measurements. The Cmapp data for alkan-1-ols when plotted against ψ1, the concentration of hydroxyl groups in the mixture, follow a single corresponding states curve for each of the solvents. For all alkan-1-ols, CpE display the following behaviour: CpE (oct-1-yne) CpE (oct-1-ene)>CpE (n-octane) at higher alcohol concentrations, the cross-over point being between 0.1 and 0.2 alcohol mole fraction. To interpret the data, the Treszcanowicz–Kehiaian (TK) model for associated liquids has been used. The parameters of the model, i.e. volumetric equilibrium constants and enthalpies of formation for alcohol–unsaturated hydrocarbon 1:1 complexes have been fitted to the dilute alcohol data. With these parameters, the TK model is able to give correct qualitative predictions of the CpE results throughout the concentration range. Using the Flory lattice model, the volumetric equilibrium constants were transformed into a unique or intrinsic equilibrium constant, which is independent of molecular size and describes the alcohol–alkene and alcohol–alkyne association. A detailed analysis of the data for hexan-1-ol+oct-1-yne and hexan-1-ol+oct-4-yne indicates that the dominating interaction in the formation of the alcohol–unsaturated hydrocarbon complex is that occurring between the proton of the hydroxy group of the alcohol and the negative electron density in the double or triple bond, producing what can be termed a H-bond. Using the parameters obtained when analyzing excess volumes VE and excess enthalpies HE for similar and common systems (T. M. Letcher etal., FluidPhaseEquilib., 1995, 112, 131), the ERAS model was used to predict CpE, finding that it is unable to give a satisfactory rendering of the present heat capacity data.

Excess volumes of the ternary system ethanol+tetrahydrofuran+cyclohexane at 298.15 K

By means of a vibrating tube densimeter, the excess molar volumes V E at 298.15 K have been determined in the whole composition domain for the ternary system ethanol+tetrahydrofuran+cyclohexane and for the relevant binary mixtures. While ethanol+tetrahydrofuran shows slight V E values and a S-shaped V E curve, the other two binaries have similar largely positive V Es. The ternary V E surface is almost always positive with a small maximum. The binary V E data have been described with different correlation equations. The capabilities of different models of either predicting or reproducing the ternary data have been compared. The behaviour of V E and of the partial molar excess volumes of the components in the ternary system is discussed and it is found that hydrogen-bonding decreases with alcohol dilution and increases with the tetrahydrofuran solution content.

Alcohol removal of the epithelium for excimer laser ablation: Outcomes analysis

Purpose: To determine whether removing the corneal epithelium by dilute alcohol is equal to other epithelial removal techniques.Setting: The Bochner Eye Institute, Toronto, Ontario, Canada.Methods: Epithelium was removed using 25% alcohol placed on a circular pledget; the alcohol remained on the cornea for 3 minutes. Irrigation was performed with cold balanced salt solution. The epithelium was then lifted with forceps and removed. Ninety-one eyes having photorefractive keratectomy for low myopia (less than 8.00 diopters) were treated; 41 eyes were followed between 4 and 10 months (mean 6 months). Complications such as haze and loss of best corrected visual acuity (BCVA) were recorded.Results: All alcohol-treated eyes achieved a BCVA of 20/40 or better; 65.9% had 20/20 and 92.7%, 20/25 or better. There were no complications or adverse effectsConclusion: Epithelial removal using 25% alcohol did not adversely affect the algorithms used with the VISX 20/20 excimer laser, indicating the technique is safe, predictable, and effective. There was no significant loss of BCVA, toxic effects, or stromal hydration.

Correlation and prediction of infinite-dilution partial molar volumes of organic solutes in SC CO 2 using the Peng-Robinson and PHCT equations of state and the LCVM EOS/G E model

An extensive infinite-dilution partial molar volume (PMV) data base of various liquid and solid solutes in supercritical carbon dioxide, including the very recent experimental partial molar volume data reported by Spicka et al. [B. Spicka, A. Cortesi, M. Fermeglia, I. Kikic, Determination of partial molar volumes at infinite dilution using SFC technique, J. Supercrit Fluids 7 (1994) 171] and Cortesi et al. [A. Cortesi, I. Kikic, B. Spicka, K. Magoulas, D. Tassios, Determination of partial molar volumes at infinite dilution of alcohols and terpenes in supercritical carbon dioxide, J. Supercrit. Fluids 9 (1996) 141] is used for a comprehensive study of the capabilities of three different thermodynamic models for the prediction of infinite-dilution partial molar volume data. The models are two equations of state, i.e. the well-known Peng-Robinson cubic EoS and the perturbed hard-chain theory (PHCT) EoS, and an EoS/G E model, the recently proposed LCVM group-contribution model. Correlation of the whole data base has been also considered with the Peng-Robinson EoS in order to determine the capability of a cubic equation of state to describe PMV data. Generally, all models were found to be semi-quantitative in the PMV prediction, especially in the range of the PMV minimum. Satisfactory prediction results are obtained using the Peng-Robinson EoS with interaction parameters from phase equilibrium data, and the fully predictive LCVM model. Both LCVM and the PHCT models tend to overpredict the PMV of n-alkanes in carbon dioxide in the high-pressure region, while PHCT always gives less satisfactory prediction results.

Determination of partial molar volumes at infinite dilution of alcohols and terpenes in supercritical carbon dioxide

The use of supercritical fluid chromatography for determining partial molar volumes of alcohols and terpenes at infinite dilution in supercritical CO 2 is presented and discussed. Partial molar volumes at infinite dilution are obtained from the variation of the retention properties with the density of mobile phase at 313.15 K and in the pressure range from 85 to 280 bar.

Effects of downstream pressure on pervaporation performance for dilute alcohol solution using porous hydrophobic membranes.

In the present study, we investigated the relationship between pervaporation separation properties of dilute ethanol solutions and the separation conditions, especially downstream pressure using porous hydrophobic membranes

Dilute single and mixed solute systems in a spiral wound reverse osmosis module: Part II. Experimental data and application of the model

In Part I of this paper a system design model for a spiral wound reverse osmosis module was developed. The model allows for the choice of membrane mass transport model and describes material balances, pressure drop, and mixing in the feed channel. In the current paper this model is used to analyze data for single and mixed solute experiments with dilute aqueous alcohol solutions. A commercial FilmTec FT-30 brackish water spiral wound membrane module was used in all experiments. The unknown parameters in the model determined from single solute experimental data can be used to predict the performance for multiple solute experiments. The model predictions for both single and multiple solute separations are consistent with the experimental results over a wide range of pressures and feed flow rates. The mesh step model was shown to describe the mixing in the feed channel spacer well. A further result is the solute transport parameters from the Kimura Sourirajan Analysis were found to be correlated to the steric or polar Taft parameters for this membrane module.

Adsorption of Rhodococcus Strain GIN-1 (NCIMB 40340) on Titanium Dioxide and Coal Fly Ash Particles

Rhodococcus strain GIN-1 (NCIMB 40340) can be used to enrich and isolate a titanium-rich fraction from coal fly ash. The gram-positive bacterium was isolated by its ability to adhere strongly and rapidly to suspended particles of pure titanium dioxide or coal fly ash. Adsorption depends on the salt concentration and occurs in seawater. Lowering of the salt concentration or washing of particles with pure water did not, however, cause desorption of the bacteria from TiO(2) particles; this was achieved by strong alkaline treatment or combined treatment with sodium dodecyl sulfate and urea but not with dilute acids, alcohols, or cationic or nonionic detergents. The bacterium exhibits higher affinity towards oxides of Ti and Zn than to other oxides with similar distribution of particle size. Moreover, it adheres much faster to TiO(2) than to magnetite (Fe(3)O(4)) or Al(2)O(3). After about 1 min, more than 85% of the cells were adsorbed on TiO(2), compared with adsorption of only 10 and 8% to magnetite and Al(2)O(3), respectively. Adsorption of the bacteria on TiO(2) occurs over a pH range of 1.0 to 9.0 and at temperatures from 4 to over 80 degrees C. Scanning electron microscopy combined with X-ray analysis revealed preferential adherence of the bacterium to coal ash particles richer in Ti. Stronger adhesion to TiO(2) was also demonstrated in the translocation of bacteria, preadsorbed on magnetite, to TiO(2) particles. The temporary co-adhesion to magnetite and TiO(2) was exploited for the design of a prototype biomagnetic separation process in which bacterial cells serve as an adhesive mediator between magnetite and TiO(2) particles in a mixture of Al, Si, and Ti oxides that simulates their proportion in the ash.

Volumetric Properties of Dilute Aqueous Alcohol Solutions at Different Temperatures

Abstract The densities of dilute aqueous solutions of normal alcohols (from methanol to 1-hexanol) and branched-chain alcohols (2-butanol, 2-methyl-1-propanol, and 2,2-dimethyl-1-propanol) were measured at 5, 15, 25, 35, and 45 °C by means of an oscillating-tube densimeter. The apparent molar volumes of the alcohols in aqueous solutions were determined. The temperature dependences of the limiting partial molar volume, excess partial molar volume, concentration dependence, and methylene group contribution to volume were discussed. An alternative analysis based on the use of specific units instead of molar units was also attempted. The characteristic volumetric behavior of aqueous alcohol solutions is more pronounced for shorter- or branched-chain alcohols rather than hydrophobic alcohols. There is no definitive evidence that so-called hydrophobic hydration around the alkyl groups of alcohol in water is accompanied by a prominent volume change. The unique properties, such as negative partial molar expansion, may originate from the hydrogen-bonding interactions between water and alcohol OH groups.

Characteristics of reciprocating screen-plate bubble column with dilute alcohol solutions

Characteristics of a reciprocating screen-plate bubble column were experimentally determined with dilute alcohol solutions. Results show that the addition of ethanol up to the concentration of 0.8 wt% produces very large gas holdups and overall mass transfer coefficients, in comparison with conventional bubble columns. The plate agitation was shown to cause increases not only in the interfacial area “a” but also in the individual mass transfer coefficient kL when the speed of reciprocation was high. On a determine de facon experimentale les caracteristiques ďune colonne a bulles a plateaux-tamis reciproques au moyen de solutions ďalcool dilue. Les resultats indiquent que ľaddition ďethanol dans des concentrations allant jusq'a 0,8% en poids produit des retentions de gaz et des coefficients de transfert de matiere globaux tres eleves comparativement aux resultats obtenus avec les colonnes a bulles classiques. On montre que ľagitation des plateaux entraǐne une augmentation non seulement dans la surface interfaciale «a» mais aussi dans le coefficient de transfert de matiere individuel kL lorsque la vitesse de pulsation est elevee.

Membrane separation of low volatile organic compounds by pervaporation and vapor permeation

Pervaporation of dilute benzyl alcohol solutions was studied using polydimethylsiloxane (PDMS) membranes. The membrane performance was investigated under various temperatures, downstream pressures and feed concentrations. The benzyl alcohol concentration in the permeate decreased dramatically by increasing the downstream pressure, but increased by increasing the operating temperature. The separation and recovery of benzaldehyde from nitrogen was also investigated. Polyetherimide flat sheet membranes were prepared and then coated with silicone material. The performance of membranes in both coupon form and spiral-wound configuration was studied. When the experimental results from both configurations were compared, it was found that for the same material the membrane coupons had higher separation efficiency than the spiral-wound prototype modules. The ratio of benzaldehyde mole fraction in the permeate to the feed reached 500 for a small membrane coupon of effective surface area 10.2 cm 2. This ratio was only 26 for the prototype modules, which can be attributed to some limitations of the membrane system design. These limitations are discussed and some recommendations to improve the performance are given.