Vitrified dilute aqueous solutions. 4. Effects of electrolytes and polyhydric alcohols on the glass transition features of hyperquenched aqueous solutions

1991 ◽  
Vol 95 (26) ◽  
pp. 10777-10781 ◽  
Author(s):  
Klaus Hofer ◽  
Georg Astl ◽  
Erwin Mayer ◽  
G. P. Johari
Keyword(s):  
Glass Transition ◽  
Aqueous Solutions ◽  
Polyhydric Alcohols ◽  
Dilute Aqueous Solutions

scholarly journals Synthesis, structure and properties of oligomeric ionic liquids of highly branched structure and special features of their self-arrangement

2021 ◽  
pp. 199-209
Author(s):  
Valery V. Shevchenko ◽  
◽  
Alexandr V. Stryutsky ◽  
Mariana A. Gumenna ◽  
Nina S. Klimenko ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Ionic Conductivity ◽  
Nitrogen Atom ◽  
Aqueous Solutions ◽  
Alkyl Chain ◽  
Dilute Aqueous Solutions ◽  
Average Size

Synthesis, features of structural organization and behavior in aqueous solution of amphiphilic reactive aprotic cationic oligomeric ionic liquids obtained on the basis of a mixture of oligomeric amino- and hydroxyl-containing silsesquioxanes were considered. The dependence of the glass transition temperature, the value of ionic conductivity, self-organization in dilute aqueous solutions and the ζ-potential on the length of the alkyl substituent near the quaternary nitrogen atom in the composition of the synthesized compounds was shown. It was found that quaternization of the tertiary nitrogen atom of the starting oligomer causes a sharp decrease in the glass transition temperature. The value of the latter increases with an increase in the length of the hydrophobic alkyl fragments due to their association. In this case the ionic conductivity under anhydrous conditions decreases and at temperatures above 100°C drops by almost an order of magnitude. The maximum conductivity was reached for the oligomeric ionic liquid with the short alkyl chain and its value was 10-3 S/cm at 120oC. In dilute aqueous solutions the synthesized oligomeric ionic liquids with the short alkyl chain form aggregates with an average size of 100 nm while increasing the length of the alkyl chain prevents aggregation of silsesquioxane nuclei and leads to formation of unimolecular micelles with an average size of 3 nm

The reactions of oligoalcohols with arsenic, arsenous, boric and germanic acids

1980 ◽  
Vol 45 (10) ◽  
pp. 2645-2655 ◽  
Author(s):  
Antonín Mikan ◽  
Miloš Bartušek
Keyword(s):  
Aqueous Solutions ◽  
Equilibrium Constants ◽  
Dilute Aqueous Solutions

The reactions of sorbitol, mannitol, adonitol, dulcitol, glucose and glycerol with H3AsO4, H3AsO3, H3BO3 and GeO2 acids in dilute aqueous solutions were studied by potentiometric neutralization titrations. The formation of the following chelates was demonstrated: As(V)L3-, As(III)L(OH)2-, HAs(III)L(OH)2, BL2-, GeL2(OH)- and GeL32- and the equilibrium constants for their formation were found. Conditions for formation of these chelates of organic oligohydroxy compounds are discussed.

Study of potential oscillations during reaction of an aluminium single crystal with an aqueous KOH solution

1990 ◽  
Vol 55 (2) ◽  
pp. 345-353 ◽  
Author(s):  
Ivan Halaša ◽  
Milica Miadoková
Keyword(s):  
Aqueous Solutions ◽  
Single Crystal ◽  
Single Crystals ◽  
Periodic Potential ◽  
Optimum Conditions ◽  
Potential Oscillations ◽  
Dilute Aqueous Solutions ◽  
Experimental Findings ◽  
Kinetics Of

The authors investigated periodic potential changes measured on oriented sections of Al single crystals during spontaneous dissolution in dilute aqueous solutions of KOH, with the aim to find optimum conditions for the formation of potential oscillations. It was found that this phenomenon is related with the kinetics of the reaction investigated, whose rate also changed periodically. The mechanism of the oscillations is discussed in view of the experimental findings.

A tensammetric study of polyacrylamides, including their determination

1988 ◽  
Vol 66 (10) ◽  
pp. 2658-2663 ◽  
Author(s):  
Truis Smith-Palmer ◽  
Byron R. Wentzell ◽  
John C. Donini ◽  
Robert J. Jerrard
Keyword(s):  
Aqueous Solutions ◽  
Limits Of Detection ◽  
Dilute Aqueous Solutions ◽  
Phase Sensitive

Phase-sensitive tensammetry is shown to be a convenient and useful way to analyse polyacrylamides and associated derivatives (pams) in dilute aqueous solutions. Standard curves were obtained with ranges varying from 9 to 25 ppm and limits of detection varying from 0.7 to 2 ppm. Ways to change the range and sensitivity are discussed and demonstrated. Typical interferences and their effects are tabulated, and the analysis of pams in coal washings is discussed. The analysis of certain mixtures of polyacrylamides is shown to be possible.

Motions of water molecules in dilute aqueous solutions of tertiary butyl alcohol; a neutron scattering study of hydrophobic hydration

1970 ◽  
Vol 319 (1537) ◽  
pp. 189-208 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Water Structure ◽  
Hydrophobic Hydration ◽  
Step Length ◽  
Solute Concentration ◽  
Butyl Alcohol ◽  
Tertiary Butyl ◽  
Self Diffusion ◽  
Dilute Aqueous Solutions ◽  
Neutron Scattering Study

Cold neutron inelastic scattering experiments have been performed on dilute aqueous solutions of (CD 3 ) 3 COH and of solutions of (CH 3 ) 3 COH in D 2 O at 21 °C. From the broadening of the quasi-elastic peak and independently determined self-diffusion coefficients ( D ), diffusive lifetimes ( c ) of H 2 O molecules have been calculated as functions of solute concentration. The product Dc is insensitive to concentration, giving a mean diffusion step length of 0.14 nm. The inelastic portion of the spectrum, reflecting lattice-like hydrogen bonding modes indicates that the solute enhances the water ‘structure’ but that such structure bears no resemblance to ice.

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