Liquid mixtures involving complex formation : Extensions of the ideal associated solution theory

1977 ◽  
Vol 30 (7) ◽  
pp. 1401 ◽  
Author(s):  
DV Fenby ◽  
A Chand ◽  
A Inglese ◽  
JE Grolier ◽  
HV Kehiaian

Extensions of the ideal associated solution theory which take into account intermolecular interaction and/or size factors are derived and applied to triethylamine+ CHCl3 and diethyl ether+CHCl3. Evidence is presented for non-hydrogen-bonding specific interactions between the unlike molecules in these systems. Theories that do not take this into consideration are likely to be unsatisfactory for the determination of hydrogen-bond properties. With respect to the evaluation of ?net complex formation? properties, the extensions considered do not represent significant improvements of the simple theory. The molar enthalpies of mixing of triethylamine+CH3CCl, and diethyl ether+ CH3CCl3 have been measured at 288.15 and 298.15 K.

1989 ◽  
Vol 67 (7) ◽  
pp. 1153-1157 ◽  
Author(s):  
John F. Smith ◽  
Loren G. Hepler

We have made new measurements of the enthalpies of adding cyclohexane to mixtures of chloroform + triethylamine + cyclohexane at 25 °C. The results of these measurements have been analysed in terms of the ideal associated solution model to obtain ΔHθ for the dissociation of the chloroform-triethylamine complex. Our value of ΔHθ is in excellent agreement with a published value that was obtained from results of measurements on binary mixtures of chloroform + triethylamine. This agreement indicates that it is usefully accurate to treat mixtures of chloroform + triethylamine + cyclohexane as ideal mixtures of chloroform, triethylamine, cyclohexane, and chloroform-triethylamine complex. This result has important implications for studies of associated systems dissolved in "inert" solvents and helps to provide a connection between complex formation in dilute solutions and in binary systems (A + B, no solvent). Keywords: ideal associated solution model, chloroform, triethylamine, inert solvent, hydrogen bonded complex.


1989 ◽  
Vol 67 (7) ◽  
pp. 1225-1229 ◽  
Author(s):  
L. Barta ◽  
Z. S. Kooner ◽  
L. G. Hepler ◽  
G. Roux-Desgranges ◽  
J.-P. E. Grolier

We have made new measurements of excess heat capacities and excess volumes of mixtures of chloroform and dioxane. In combination with published vapor pressures and excess enthalpies the results have been analyzed using the ideal associated solution model to yield K, ΔHθ, ΔCpθ, and ΔVθ for the formation of AB and A2B complexes. It is demonstrated that the ideal associated solution model is consistent with all of the available thermodynamic data for this system, indicating that chemical interactions of the two components can account for nearly all of the deviations from ideal solution behavior. The results of our thermodynamic analysis are discussed in relation to the results of similar analyses of other systems in which there are strong chemical interactions of chloroform with electron-donor molecules. Keywords: complex formation, hydrogen bonding, ideal associated solution model, chloroform, 1,4-dioxane.


1989 ◽  
Vol 67 (3) ◽  
pp. 446-448 ◽  
Author(s):  
Richard P. Schutte ◽  
Terry C. Liu ◽  
Loren H. Hepler

Viscosities and densities of highly non-ideal mixtures of chloroform (A) + triethylamine (B) have been measured at 25 °C. It has been shown that the Grunberg equation (one adjustable parameter) can account for these viscosities over the whole range of compositions. It has also been shown that a new combination of the ideal associated solution model, based on consideration of an equilibrium of the type A + B = AB, with an ideal viscosity equation (also one adjustable parameter) accounts more accurately for all of the viscosities. This latter treatment also has the advantage of offering a clear pictorial model of the mixtures. Keywords: viscosity of solution, complex formation in solution, chloroform + triethylamine, triethylamine + chloroform.


1987 ◽  
Vol 16 (9) ◽  
pp. 745-752 ◽  
Author(s):  
Jean-Pierre E. Grolier ◽  
Genevieve Roux-Desgranges ◽  
Zorawar S. Kooner ◽  
John F. Smith ◽  
Loren G. Hepler

2013 ◽  
Vol 12 (7) ◽  
pp. 460-465
Author(s):  
Sameer Amereih ◽  
Zaher Barghouthi ◽  
Lamees Majjiad

A sensitive colorimetric determination of fluoride in drinking water has been developed using a polymeric zirconium complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline as fluoride reagents. The method allowed a reliable determination of fluoride in range of (0.0-1.5) mg L-1. The molar absorptivity of the complex formation is 7695 ± 27 L mol-1 cm-1 at 460 nm. The sensitivity, detection limit, quantitation limit, and percentage recovery for 1.0 mg L-1 fluoride for the proposed method were found to be 0.353 ± 0.013 μg mL-1, 0.1 mg L-1, 0.3 mg L-1, and 101.7 ± 4.1, respectively.


1990 ◽  
Vol 55 (5) ◽  
pp. 1149-1161
Author(s):  
Jiří Závada ◽  
Václav Pechanec ◽  
Oldřich Kocián

A powerful anion effect destabilizing alkali ion-crown complex formation has been found to operate in moderately concentrated protic (H2O, CH3OH, C2H5OH) solution, following the order HO- > AcO- > Cl- > Br- > NO3- > I- > NCS-. Evidence is provided that the observed effect does not originate from ion-pairing. A simple explanation is provided in terms of concordant hydrogen bond bridges of exalted stability between the gegenions, M+···OR-H···(OR-H)n···OR-H···A-. It is proposed that encapsulation of alkali ion by the macrocyclic ligand leads to a dissipation of the cation charge density destroying its ability to participate in the hydrogen bond bridge. An opposition against the alkali ion-crown complex formation arises accordingly in the solution in dependence on strength of the hydrogen bridge; for a given cation, the hydrogen bond strength increases with increasing anion charge density from NCS- to HO-(RO-). It is pointed out, at the same time, that the observed anion effect does not correlate with the known values of activity coefficients of the individual alkali salts which are almost insensitive to anion variation under the investigated conditions. As a resolution of the apparent paradoxon it is proposed that, in absence of the macrocyclic ligand, the stabilizing (concordant) bonding between the gegenions is nearly balanced by a destabilizing (discordant) hydrogen bonding between the ions of same charge (co-ions). Intrinsic differences among the individual salts are thus submerged in protic solvents and become apparent only when the concordant bonding is suppressed in the alkali ion-crown complex formation.


Author(s):  
David M Hudson

Abstract Freshwater crustaceans are distributed throughout the montane and lowland areas of Colombia, and are therefore a useful indicator group for how aquatic species will respond to climate change. As such, metabolic determination of physiological performance was evaluated for the Colombian pseudothelphusid crab, Neostrengeria macropa (H. Milne Edwards, 1853), over a temperature range inclusive of current temperatures and those predicted by future scenarios in the plateau around the city of Bogotá, namely from 8 °C to 30 °C. The performance results mostly aligned with previous exploratory behavioral determination of the ideal temperature range in the same species, although the metabolism increased at the highest temperature treatments, a point when exploratory behavior declined. These results indicate that this species of montane crab behaviorally compensates for increased thermal stress by decreasing its physical activity, which could have negative predator-prey consequences with changes to community structure as different species undergo climate-mediated geographic range shifts in the region. As this species is endemic to the plateau surrounding Bogotá, it also experiences a number of other stressors to its survival, including infrastructure development and invasive species.


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