T-butyl Alcohol Water Mixtures Research Articles

Small-angle X-ray scattering from poly(methylmethacrylate) in aqueous solutions oft-butyl alcohol

Segment-segment interaction of poly(methylmethacrylate) in t-butyl alcohol-water mixtures in poor solvent regime was studied. From the small-angle X-ray scattering measurements of semidilute solution range, the binary and ternary cluster integrals of polymer segments were determined from concentration dependence of the correlation length at various temperatures just above the upper critical solution temperature. We have calculated the contributions of the segment–segment interaction to the entropy and enthalpy from the measured temperature dependence of these interaction parameters and found that both quantities are negative and decrease with decreasing t-butyl alcohol content. FT-IR absorption peak of carbonyl group of poly(methylmethacrylate) shifts to the lower frequency with increasing water content. The implications of these findings are discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2195–2199, 1999

Pressure Effect on Proton Jumps in t-Butyl Alcohol–Water Mixtures at 25°C

Abstract The limiting molar conductances, Λ°, of hydrochloric acid and potassium chloride in 2,3,5,7,10, and 25 mol% t-butyl alcohol (TBA)–water mixtures were determined at 25°C as a function of the pressure up to 2000 kgf cm−2 (1 kgf cm−2=0.9807×105 Pa) from the conductances measured within a dilute concentration range. In each solvent mixture the value of Λ° (HCl) was about three- to five-times larger than that of Λ° (KCl) The anomalous excess proton conductance, λ°E, as estimated by the equation [λ°E=Λ° (HCl)−Λ°(KCl)], was found to increase with increasing pressure in 2,3,5,and 7 mol% TBA–water mixtures, but to decrease in 10 and 25 mol% TBA-water mixtures. The rate of increase with pressure of the excess proton conductance normalized to the molar concentration of water in the mixture was largest in a 2 mol% TBA mixture, and its magnitude decreased in the order: 2>3>0>5>>7>>10>>25 mol% of TBA. These results are compared with those obtained in ethanol–water mixtures and are discussed in relation to the effect of alcohol molecules on the water structure in the mixtures: the three-dimensional network of water in TBA–water mixtures is more stable at a lower mol% of alcohol, and collapses more rapidly with increasing alcohol content than in ethanol–water mixtures.

Gibbs free energies of transfer of the alkali-metal chlorides from water into t-butyl alcohol-water mixtures

The standard Gibbs free energies of transfer Δ G XXX t of the alkali-metal chlorides MCI from water (W) into 5–90 wt.% t-butyl alcohol (TBA)-water mixtures (S) were determined from EMF measurements performed on the double cell Ag, AgCl¦MCl( m), S¦M(Hg)¦MCl( m), W¦AgCl,Ag at 25 °C in the molality range of MCI from 0.001–0.100 mol kg −1. The value of Δ G XXX t rises from Li + to Na + and falls from K + to Cs +, with a maximum between Na + and K + whose position depends on the solvent composition. The standard potentials of the cell M¦MCl( m), S¦AgCl,Ag in these 10 TBA-water mixtures were also determined. The results have been interpreted and discussed in terms of solute-solvent interactions.

Dielectric, ultrasonic and carbon-13 nuclear magnetic resonance relaxation measurements of t-butyl alcohol–water mixtures

Dielectric, ultrasonic and 13C nuclear magnetic resonance relaxation measurements are reported on mixtures of t-butyl alcohol and water over the temperature range 278–308 K. Supporting measurements of the refractive index, density and viscosity are also presented. Deviations from ideal mixing behaviour are observed in the volumes of mixing, permittivities and adiabatic compressibilities of the mixtures. The location of the minima in the excess occurring at different compositions depend upon the method of measurement. Similarly the relaxation behaviour, as observed using different techniques, reveals different aspects of the motion of the molecules in the fluid. The various effects observed are rationalized in terms of a model in which it is assumed that t-butyl alcohol dimers and trimers and various hydrated forms play an important role in determining the structure of these mixtures.

Partial molar volumes in aqueous mixtures of nonelectrolytes. II. Isopropyl alcohol

Densities of isopropyl alconol-water mixtures were measured over the entire mole fraction range at 5, 15, 25, 35 and 45°C. Apparent and partial molar volumes and partial molar expansibilities were derived for both components. The results were compared with those of a previous investigation of t-butyl alcohol-water mixtures.

Standard thermodynamics of transfer: V. The silver and silver salt electrodes in t-butyl alcohol-water mixtures at various temperatures

From the electromotive force measurements of cells with liquid-junction potentials, the standard potentials of the silver, silver-silver halide, silver-silver pseudohalide and silver-silver oxyhalide electrodes have been determined in 10 and 20 wt.% t-butyl alcohol-water mixtures at 5, 15. 25 and 35 °C. The values of the standard potentials have been used to evaluate the primary medium effects and the standard thermodynamic functions for the transfer of the ion from water to the respective solvent media. The results have been discussed in relation to the breakdown of the structure of water on the addition of t-butyl alcohol.

Solubilities of caesium and thallium(I) triphenylcyanoboronates and of caesium and mercury(II) tetraphenylboronates in alcohol + water mixtures; Transfer chemical potentials of the BPh 3(CN) −, BPh 4 −, TI +, and Hg 2+ ions

Solubilities(298.2 K) are reported for caesium and thallium(I) triphenylcyanoboronates in water and in methanol-, ethanol-, and t-butyyl alcohol-water mixtures containing up to 40% (by volume) alcohol. Solubilities (298.2 K) are also reported for caesium tetraphenylboronate in t-butyl alcohol- and ethylene glycol-water mixtures and for mercury(II) tetraphenylboronate in t-butyl alcohol-water mixtures, again up to 40% (by volume) alcohol. From these data and published transfer chemical potentials (based on various extrathermodynamic assumptions) for appropriate ions, we have derived estimates for the transfer chemical potentials of BPh 3(CN) − and TT + to methanol, ethanol, and t-butyl alcohol-water mixtures, for BPh 4 − to t-butyl alcohol- and ethylene glycol-water mixtures, and for Hg 2+ to t-butylalcohol-water mixtures.

Enthalpies of solution of 2,2′-bipyridyl, 1,10-phenanthroline, and 1,10-phenanthroline monohydrate

Enthalpies of solution are reported for 1,10-phenanthroline and its monohydrate in water and in benzene, and for 2,2′-bipyridyl in water and in series of methanol–water and t-butyl alcohol–water mixtures.

The stabilities of Meisenheimer complexes. Part 26. The reactions of some aromatic nitro-compounds with base in t-butyl alcohol–water mixtures

Kinetic and equilibrium data are reported for the reaction of three nitro-compounds with tetramethylammonium hydroxide in t-butyl alcohol containing water. In all solvent systems studied the reactive nucleophile is thought to be the hydroxide ion rather than the t-butoxide ion. The reaction of 1,3,5-trinitrobenzene with base gives a σ-adduct, while 1-chloro-2,4-dinitrobenzene gives 2,4-dinitrophenol. The rates of both these reactions fall rapidly with increasing water in the solvent. In contrast the rate of formation of picric acid from the third substrate, picryl chloride, increases with water content due to the initial formation of the 3-hydroxy-adduct.

Solvent effects on discrimination in the dissociative substitution of pentacyano(ligand)ferrate(II) comptexes in alcohol–water mixtures

Solvent effects on the discriminatory properties of the transient [Fe(CN)5]3– intermediate in the dissociative (D) substitution at the complex ions [Fe(CN)5L]3–(L = 3- or 4-cyanopyridine) are described. The solvents employed are methanol—, ethanol—, and t-butyl alcohol–water mixtures; in each case the incoming group is cyanide ion.

Kinetics of aquation of tris(5-nitro-1,10-phenanthroline)iron(II) in acetone–water and in t-butyl alcohol–water mixtures: endostatic analysis of activation parameters

Rate constants and derived thermodynamic activation parameters are reported for the aquation of [Fe(5NO2-phen)3]2+ in acetone–water and in t-butyl alcohol–water mixtures. The data have been analysed to obtain kinetic activation parameters for reaction in corresponding mixtures where the ratio of activities of the two solvent components is constant, i.e. under endostatic conditions. A method is described for calculating endostatic activation parameters from kinetic data and molar thermodynamic excess functions for the binary mixture. The results of these calculations are discussed in the light of the known properties and structures of the solvent mixtures. The solvent dependence of the activation Gibbs function, ΔGα‡. calculated under endostatic conditions for the aquation of the iron complex, reflects changes in solvent structure more markedly than the conventional activation parameter ΔG‡ calculated directly from the rate constant using transition-state theory. This trend has been previously reported for the hydrolysis of 2-chloro-2-methylpropane, thereby indicating that the mechanisms of aquation for both reactants are similar, ie. dissociative.

Solubilities of caesium hexachlororhenate(IV), hexabromorhenate(IV), and tetraoxorhenate(VII) in alcohol–water mixtures, and their relation to cosolvent characteristic volume

Solubllities of Cs2[ReCl6] in methanol–, ethanol–, and t-butyl alcohol–water mixtures, and of Cs2[ReBr6] and Cs[ReO4] in methanol–water, mixtures, are reported. Correlation of these solubilrties with various solvent and solubllity parameters is discussed; a simple correlation of solubilities with solvent composition and cosolvent characteristic volume is remarkably satisfactory.

Standard potentials of the silver–silver chloride electrode in t-butyl alcohol–water mixtures and the thermodynamics of solutions of hydrochloric acid at different temperatures

Electromotive force measurements of cells of the type Pt,H2(g, 1 atm)|HCl(m), ButOH (X),H2O(100 –X)|AgCl-Ag at 5, 15, 25, 35, and 45°C have been used to evaluate (i) the standard potentials of the Ag–AgCl electrode for X= 10, 20, 40, and 70%(w/w) by a polynomial curve-fitting technique, (ii) the mean molal activity coefficients of hydrochloric acid (0·005–0·2 mol kg–1), (iii) the primary medium effects, (iv) the relative partial molal enthalpies, and (v) the thermodynamic functions for the transfer of HCl from water to the respective solvent media. The values of Em° in each solvent have been represented as a function of temperature. The significance of the results has been discussed in relation to the acid–base properties and the breakdown of the structure of water on the addition of t-butyl alcohol.

Aquation of penta-amminechlorocobalt(III), trans-bisethylenediaminedi-chlorocobalt(III), and related complexes in mixed aqueous solvents

Rates are reported for spontaneous aquation of [Co(NH3)5Cl]2+, and trans-[Co(en)2Cl2]+, and of mercury(II)-assisted aquation of [Co(NH3)5Cl]2+ and [Rh(NH3)5Cl]2+, in a range of binary mixed solvents, including methanol-, ethanol-, dioxan-, acetone-, acetic acid-, and t-butyl alcohol-water mixtures. These results, and previously published results on similar complexes, are discussed in terms of the Grunwald–Winstein treatment of solvolyses in mixed solvents.

Application of spectroscopic and relaxation techniques to the study of t-butyl alcohol–water mixtures

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