Thermodynamic properties of water in the water-poor region of binary water + alcohol mixtures

2005 ◽  
Vol 83 (5) ◽  
pp. 420-429 ◽  
Author(s):  
Karin Liltorp ◽  
Peter Westh ◽  
Yoshikata Koga
Keyword(s):  
Hydrogen Bonding ◽  
Composition Dependence ◽  
Pure Water ◽  
Molar Enthalpy ◽  
Partial Molar Enthalpy ◽  
Alcohol Water ◽  
Mixing Schemes ◽  
Alcohol Mixtures ◽  
Excess Partial Molar Enthalpy ◽  
Water Alcohol

In our previous thermodynamic studies, we suggested that alcohol molecules in water-poor water + alcohol mixtures exist as alcohol clusters in a form similar to the pure alcohols. Here, we use calorimetry and densitometry to investigate how H2O interacts with alcohol clusters in water-poor binary aqueous mixtures of 12 different alcohols. The composition dependence of the measured excess partial molar enthalpy and volume of water (HEW and VEW), along with entropy data calculated from HEW and literature data for excess chemical potentials, showed that in water-poor solutions of small alcohols such as methanol, ethanol, and 1-propanol, mutual water–water interactions are endothermic, but entropically favorable. Conversely, in long-chain solvents such as 1-octanol and 1-decanol, the interaction is exothermic and entropically unfavorable. We suggest that these observations reflect water–alcohol hydrogen bonding in short-chain solvents and water clustering with more hydrogen bonding than in pure water or "dewetting" in mixtures of the longer alcohols, respectively. The composition dependence of HEW was also used to locate anomalies that specify the boundary between the mixing schemes characterizing the intermediate and the water-poor regions of alcohol + water mixtures.Key words: aqueous alkane-mono-ols, excess partial molar enthalpy, entropy and volume, mixing schemes.

Cononsolvency in the ‘drunken’ state: the thermoresponsiveness of a new acrylamide copolymer in water–alcohol mixtures

2017 ◽  
Vol 8 (7) ◽  
pp. 1196-1205 ◽  
Author(s):  
Niklas Lucht ◽  
Steffen Eggers ◽  
Volker Abetz
Keyword(s):  
Alcohol Water ◽  
Alcohol Mixtures ◽  
Water Alcohol

This work presents the synthesis and thermoresponsiveness of a random acrylamide copolymer in alcohol–water mixtures and discusses cononsolvency phenomena.

A Luminescent Probe Study of Water/Acetonitrile Mixtures

1979 ◽  
Vol 32 (2) ◽  
pp. 271 ◽  
Author(s):  
AJ Easteal
Keyword(s):  
Salicylic Acid ◽  
Luminescence Band ◽  
Composition Dependence ◽  
Water Structure ◽  
Luminescence Spectra ◽  
Broad Emission Band ◽  
Luminescent Probe ◽  
Broad Emission ◽  
Alcohol Mixtures ◽  
Water Alcohol

Luminescence spectra for 1.0 × 10-2 mol dm-3 solutions of salicylic acid in water, acetonitrile and water/acetonitrile mixtures have been determined. In the wavelength range 300-600 nm, all spectra showed a single broad emission band. The variations of the wavelength of maximum luminescence intensity (λmax) and luminescence band half-width (Δ�) with solvent composition are similar to the composition dependence of these parameters observed previously for solutions of salicylic acid in water/alcohol mixtures. The invariance of Δ� with acetonitrile content up to approximately 15 mole% supports earlier conclusions that up to c. 15 mole% acetonitrile is accommodated within cavities in the water structure. The rapid increase in near 15 mole% acetonitrile provides further evidence for a progressive destruction of the water structure as the acetonitrile content is increased beyond c. 15 mole%.

Triplet Solvation Dynamics of Hydrogen Bonding Liquids in Confinement

2018 ◽  
Vol 232 (7-8) ◽  
pp. 1017-1039 ◽  
Author(s):  
Peter Weigl ◽  
Vincenzo Talluto ◽  
Thomas Walther ◽  
Thomas Blochowicz
Keyword(s):  
Hydrogen Bonding ◽  
Full Advantage ◽  
Experimental Method ◽  
Ccd Camera ◽  
Local Environment ◽  
Experimental Setup ◽  
Solvation Dynamics ◽  
Alcohol Mixtures ◽  
Phosphorescence Spectra ◽  
Water Alcohol

Abstract We have developed a flexible experimental setup to conduct triplet solvation dynamics (TSD) experiments. The setup is capable of exciting dyes at 355, 320 and 266 nm. Phosphorescence spectra can be recorded up to a 10 ns-resolution usually covering three decades using a grating spectrograph and a CCD camera. In this contribution, we describe the experimental setup as well as first investigations on water-alcohol mixtures, microemulsions and new dyes for TSD, i.e. naphthalene derivates, which take full advantage of this experimental method sensitive to the local environment of the dyes.

Dissolution enthalpy of NaI in water–alcohol mixtures at 288.15 and 308.15 K. Enthalpy of interaction in electrolyte–alcohol–water systems

1984 ◽  
Vol 62 (5) ◽  
pp. 856-859 ◽  
Author(s):  
Henryk Piekarski ◽  
Alina Piekarska ◽  
Stefania Taniewska-Osińska
Keyword(s):  
Mixed Solvent ◽  
Pair Interaction ◽  
Water Systems ◽  
Effect Of Temperature ◽  
Solvent Concentration ◽  
Interaction Coefficients ◽  
Enthalpic Pair Interaction Coefficients ◽  
Alcohol Water ◽  
Alcohol Mixtures ◽  
Water Alcohol

The enthalpy of NaI solution was determined in water mixtures with methanol, ethanol, propanol, and isopropanol in the entire range of mixed-solvent concentration at 288.15 and 308.15 K, and in water mixtures with s-butanol and tert-butanol in the range of 0–5 mol% alcohol at 308.15 K. The dependence of [Formula: see text] on solvent composition was studied. The enthalpic pair interaction coefficients hEN for NaI–alcohol in water and NaI–water in alcohols were determined, and the effect of temperature on hEN values in the systems under study was analyzed.

An Experimental Study of Heat Pipe Performance Using Binary Mixture Fluids That Exhibit Strong Concentration Marangoni Effects

2011 ◽  
Vol 3 (3) ◽  
Author(s):  
Kenneth M. Armijo ◽  
Van P. Carey
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Heat Pipe ◽  
Pure Water ◽  
Working Fluid ◽  
Strong Concentration ◽  
Alcohol Mixtures ◽  
Marangoni Effects ◽  
Water Alcohol

This paper summarizes the results of an experimental investigation of the performance characteristics of a gravity/capillary driven heat pipe using water/alcohol mixtures as a working fluid. This investigation specifically explored the use of water/alcohol mixtures that exhibit strong concentration-based Marangoni effects. Experiments to determine heat pipe performance were conducted for pure water and water/alcohol solutions with increasing concentrations of alcohol. Initial tests with pure water determined the optimal working fluid charge for the heat pipe; subsequent performance tests over a wide range of heat input levels were then conducted for each working fluid at this optimum value. The results indicate that some mixtures can significantly enhance the heat transfer coefficient and heat flux capability of the heat pipe evaporator. For the best mixture tested, the maximum evaporator heat flux carried by the coolant without dryout was found to be 52% higher than the value for the same heat pipe using pure water as a coolant under comparable conditions. Peak evaporator heat flux values above 100 W/cm2 were achieved with some mixtures. Evaporator and condenser heat transfer coefficient data are presented, and the trends are examined in the context of the expected effect of the Marangoni mechanisms on heat transfer.

Excess Partial Molar Enthalpy of 1-Propanol in 1-Propanol−NaCl−H2O at 25 °C:  The Effect of NaCl on Molecular Organization of H2O†

1999 ◽  
Vol 103 (15) ◽  
pp. 2981-2983 ◽  
Author(s):  
Hiroshi Matsuo ◽  
Eric C. H. To ◽  
Denise C. Y. Wong ◽  
Seiji Sawamura ◽  
Yoshihiro Taniguchi ◽  
...  
Keyword(s):  
Molar Enthalpy ◽  
Partial Molar Enthalpy ◽  
Molecular Organization ◽  
Excess Partial Molar Enthalpy
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