Apparent molal volumes and heat capacities of some alkali halides and tetraalkylammonium bromides in aqueoustert-butanol solutions

PIUS K. KIPKEMBOI, and ALLAN J. EASTEAL. Can. J. Chem. 72, 1937Chem. 72, (1994. The density and shear viscosity of mixtures of tert-butyl alcohol (BuOH) and tert-butylamine (TBA) with water have been determined for various temperatures (288 to 318 K for H20 + BuOH and 288 to 308K for H20 + TBA) over the whole composition range. Excess molar volumes and apparent molar volumes of the components of each system were calculated from the density data. In both systems the apparent molar volume of the organic component passes through a minimum in the water-rich region. Both systems exhibit large negative excess molar volumes which are essentially independent of temperature at all compositions. The two systems show pronounced maxima in their shear viscosity isotherms. Chem. 72, 1937Chem. 72, (1994. On a determint les densites et les viscosites de cisaillement de melanges d'alcool tert-butylique (BuOH) et de tert-butylamine (TBA) avec de I'eau, sur l'ensemble des compositions possibles et B diverses temptratures (allant de 288 K B 318 Kj pour H20 + BuOH et de 288 K B 308 pour H20 + TBA). Utilisant les donnkes de densite, on a calculk les volumes molaires en excbs et les volumes molaires apparents des composants de chaque systkme. Dans les deux systkmes, le volume molaire apparent du composant organique passe par un minimum dans la region riche en eau. Les deux systbmes presentes des volumes molaires en excbs largement negatifs qui sont essentiellement independants de la temperature, B toutes les compositions. Les deux systbmes prtsents des maxima importants dans leurs isothermes de viscosite de cisaillement.[Traduit par la redaction]

Section: Introductionmentioning

confidence: 99%

Densities and viscosities of binary aqueous mixtures of nonelectrolytes: tert-Butyl alcohol and tert-butylamine

Kipkemboi¹,

Easteal²

1994

“…Often the maxima observed in water-rich region of the aqueous binary mixtures are interpreted as due to an increase in water structure on the addition of non-electrolytes. A number of studies in alcohol-water mixtures (14,15), DMSO-water (12). acetone-water (16) supports this view and suggests that at higher concentrations of non-electrolyte a progressive 'destructurization' of the solvent takes place.…”

Section: Apparcrrus and Proceduresmentioning

confidence: 90%

Enthalpies of solution and single ion enthalpies of transfer from water to dioxane–water mixtures

Bhatnagar¹

1976

OM N. BHAT~AGAR Can J. Chem 54, 3487 (1976) Standard enthalples of solutions of sodlum bromlde, potasslum bronude, tetrabutyl phosphonium brom~de, tetraphenyl phosphoniu~n bromide, and sodlum tetraphenyl boron have been measured In 20C,, 44 5' ,, and 64 5(, dloxane-water mlxture. On the extra thermodynam~c assumption AAH,(Ph4P+) = AAH,(-BPh4) slngle Ion enthalples of tranifer from water to d~oxane-water mixtures have been calculated for \ arlous Ions.OM N. BHATNAGAR. Can. J. Chem. 54, 3487 (1976). On a mesurC les enthalpies standards de solution du bromure de sodium, du bromure de potassium, du bromure de tCtrabutylphosphonium, du bromure de tCtraphCnylphosphoniun~ et du tCtraphCnylbore sodium dans des mClanges dioxanne-eau k 20C$, 44.5C; et 64.5yc. En faisant I'hypothkse thermodynamique supplCmentaire que AAH,(Ph4P+) = a~H , ( -B p h~) , on a calcule, pour divers ions, les enthalpies de transfert d'ions uniques de I'eau a des melanges dioxanne-eau.[Traduit par le journal] Introduction I have been interested in the study of thermodynamic properties of electrolyte solutions in dioxane-water mixtures for some time (1-3). The solvation enthalpies of some tetraalkyl ammonium bromides in dioxane-water mixtures were reported in a recent paper (3). It was shown that the behaviour of these electrolytes was quite similar to their behaviour in water and that the structure-making capacity of tetraalkyl ammonium ions increases with the increase in the size of the ion. Thus from the studv in dioxanewater mixtures Bu4N+ ion was found to be the most active in structure promotion. It was thought to be of interest to see how this behaviour would change (i) by changing the central atom from nitrogen to phosphorus, (ii) by changing the nature of tetraalkyl ion from aliphatic ( [ G H 9]4-) t o aromatic ([C6H5]4-), (iii) by changing the small Br-ion to a bulky -BPh4 ion.In this paper the standard enthalpies of solution, AHsO, of sodium bromide, potassium bromide, tetrabutyl phosphonium bromide (BudPBr), tetraphenyl phosphonium bromide ([C6H5]4PBr) and sodium tetraphenyl boron (NaBPh4) in 207,, 44.57,, and 64.57, dioxane-water mixtures are reported. In addition, an attempt has been made to divide the standard enthalpies of transfer AAH, from water to dioxane-water mixtures into

“…The flow techniques used for volumes and heat capacities have been well described elsewhere (30)(31)(32). The densities and volumetric heat capacities of the ternary system were measured using the binary system (surfactant 2 in water W ) as reference liquid, and the apparent molar quantities V+,, and Cp,6,3 of the additive 3 were calculated from these measurements (3 1).…”

Section: Methodsmentioning

confidence: 99%

Volumes and heat capacities of transfer of ammonium salts from water to aqueous octyldimethylamine oxide at 25 °C

Hétu¹,

Desnoyers²

1988

Self Cite

. 66, 767 (1988).The effect of an additive on a water-surfactant system can be studied through thermodynamic functions of transfer of the additive from water to aqueous solutions of the surfactant. These thermodynamic functions often go through extrema in the region of the critical micellar concentration (cmc) of the surfactant. As it can be shown with a simple chemical equilibrium model, the general shape of the transfer functions is primarily related to the pair-wise hydrophobic interactions between the additive and the surfactant monomers, to a shift in the monomer-micelle equilibrium and to the distribution of the additive between the aqueous phase and the micelles. Medium and electrostatic effects are also possible, especially with ionic systems. To separate these effects and identify the salts which distribute themselves in the micelles, the volumes and heat capacities of transfer of hydrophobic ammonium salts from water to aqueous solutions of dimethyloctylamine oxide have been investigated. The short chain salts have only a small effect on monomer-micelle equilibrium by salting out the monomers, whereas the more hydrophobic ones participate also to the micellization process, shifting more strongly the surfactant monomer-micelle equilibrium.DANIEL HCTU et JACQUES E. DESNOYERS. Can. J. Chem. 66, 767 (1988).L'effet d'un additif sur un systkme eau-tensioactif peut Ctre CtudiC par le biais des fonctions de transfert de l'additif de l'eau aux solutions aqueuses du tensioactif. Ces fonctions thermodynamiques passent souvent par un extremum dans la region de la concentration micellaire critique (cmc) du tensioactif. Comme il peut Ctre dCmontrC B l'aide d'un modkle simple d'tquilibre chimique, l'allure gCnCrale des fonctions de transfert est principalement relike aux interactions hydrophobes par paires entre les monomkres de l'additif et du tensioactif, au dCplacement de 1'Cquilibre monomkres-micelles du tensioactif, ainsi qu'i la distribution de l'additif entre la phase aqueuse et les micelles. Des effets de milieu ainsi qulClectrostatiques peuvent aussi jouer un r61e important, particulikrement dans le cas de systkmes ioniques. Afin de sCparer ces effets et d'identifier les sels qui participent B la micellisation, les volumes et capacitCs calorifiques dc transfert de sels hydrophobes d'ammonium de I'eau aux solutions aqueuses d'oxyde dloctyldimCthylamine ont CtC investiguks. Les sels a courtes chaines ont seulement un petit effet sur 1'Cquilibre monomkres-micelles du tensioactif, dh a un effet de relargage, alors que les sels B plus longues chaines participent en plus i la micellisation, dCpla~ant davantage 1'Cquilibre du tensioactif.