Critical anomalies of alkaline fading of phenolphthalein in the critical solution of 2-butoxyethanol + water

Du, Zhongyu; Yin, Hang; Hao, Zhiguo; Zheng, Peng

doi:10.1063/1.4829901

Cited by 16 publications

(18 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are several recent reports of the critical slowing down of chemical reactions, for example, saponification of ethyl acetate, [1] alkaline fading of crystal violet [2] and phenolphthalein [3] in the vicinity of the LCST. Recently, new strategies of chemical reaction control by using the unique solvent environment of binary liquid mixtures at their lower critical solution temperatures (LCSTs), like water and 2-butoxyethanol (2BE), have been proposed.…”

Section: Introductionmentioning

confidence: 99%

Observation of Unusual Molecular Diffusion Behaviour below the Lower Critical Solution Temperature of Water/2‐Butoxyethanol Mixtures by using Fluorescence Correlation Spectroscopy

et al. 2014

View full text Add to dashboard Cite

The effect of solute affinity on solute diffusion in binary liquids well below the lower critical solution temperature (LCST) was studied by using fluorescence correlation spectroscopy. We measured the hydrodynamic radii of a hydrophobic and an amphiphilic fluorescent dye under systematic variation of the relative molar fractions of water/2-butoxyethanol and, for comparison, of water/methanol mixtures, which do not show phase separation. We found that the apparent hydrodynamic radius of the hydrophobic dye almost doubled in water/2-butoxyethanol, whereas it remained largely unchanged for the amphiphilic dye and in water/methanol mixtures. Our results indicate that the translational diffusion of solutes is influenced by transient local solution structures, even at temperatures well below the LCST. We conclude that, even far below LCST, different solutes can experience different environments in binary liquid mixtures depending on both the solute and solvent properties, all of which impact their reactivity.

show abstract

Section: Introductionmentioning

confidence: 99%

Observation of Unusual Molecular Diffusion Behaviour below the Lower Critical Solution Temperature of Water/2‐Butoxyethanol Mixtures by using Fluorescence Correlation Spectroscopy

et al. 2014

View full text Add to dashboard Cite

show abstract

“…There have been a number of measurements of the rate of reaction near a critical point of solution. − The experimental data for the rate constant in the forward direction, k f , have been found to be consistent with the Arrhenius equation ,− where A f is a constant pre-exponential factor, and is the apparent activation energy. Except for a few cases where no effect could be detected, ,,,, E f has been observed to increase markedly with temperature in the critical region.…”

Section: Introductionmentioning

confidence: 87%

Theory of First Order Chemical Kinetics at the Critical Point of Solution

Baird

Lang

2017

J. Phys. Chem. A

View full text Add to dashboard Cite

Liquid mixtures, which have a phase diagram exhibiting a miscibility gap ending in a critical point of solution, have been used as solvents for chemical reactions. The reaction rate in the forward direction has often been observed to slow down as a function of temperature in the critical region. Theories based upon the Gibbs free energy of reaction as the driving force for chemical change have been invoked to explain this behavior. With the assumption that the reaction is proceeding under relaxation conditions, these theories expand the free energy in a Taylor series about the position of equilibrium. Since the free energy is zero at equilibrium, the leading term in the Taylor series is proportional to the first derivative of the free energy with respect to the extent of reaction. To analyze the critical behavior of this derivative, the theories exploit the principle of critical point isomorphism, which is thought to govern all critical phenomena. They find that the derivative goes to zero in the critical region, which accounts for the slowing down observed in the reaction rate. As has been pointed out, however, most experimental rate investigations have been carried out under irreversible conditions as opposed to relaxation conditions [Shen et al. J. Phys. Chem. A 2015, 119, 8784-8791]. Below, we consider a reaction governed by first order kinetics and invoke transition state theory to take into account the irreversible conditions. We express the apparent activation energy in terms of thermodynamic derivatives evaluated under standard conditions as well as the pseudoequilibrium conditions associated with the reactant and the activated complex. We show that these derivatives approach infinity in the critical region. The apparent activation energy follows this behavior, and its divergence accounts for the slowing down of the reaction rate.

show abstract

“…In the near‐critical temperature region, large fluctuations can be found because the critical light scattering . The three‐wavelength spectrophotometry must be applied to eliminate the impact of strong scattering.…”

Section: Methodsmentioning

confidence: 99%

“…The dynamic property, such as mutual diffusion coefficient, exhibits vanishing as the temperature approaches to critical temperature . The chemical reaction rate exhibits interesting critical behaviors in the liquid–liquid critical binary solutions resulting from critical fluctuation …”

Section: Introductionmentioning

confidence: 99%

“…The rates of the SN1 hydrolysis reaction of 2‐chloro‐2‐methylbutane in isobutyric acid/water and of 2‐bromo‐2‐methylpropane in triethylamine/water reduced when the temperature was higher than the critical temperature but accelerated in the temperature region below the critical temperature . Recently, Shen et al . studied the kinetics of a first or pseudo–first‐order reversible reaction in both directions in critical binary or pseudobinary solutions and suggested that the critical slowing down effect of the reaction may be explained by dynamic and thermodynamic anomalies.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of two redox reactions in 2‐butoxyethanol and water near its critical point of solution

Duan

et al. 2019

Int J of Chemical Kinetics

Self Cite

View full text Add to dashboard Cite

The rate constants of two redox reactions Fe(CN) 4− 6 + S 2 O 2− 8 and Fe(phen) 2+ 3 + S 2 O 2− 8 in the critical solution of 2-butoxyethanol and water have been measured by using the UV spectrophotometry at the initial reaction stage. It was found that the rate constants at various temperatures for two reactions were well described by the Arrhenius equation in the noncritical region. The critical slowing down effect was detected in the critical region. The critical slowing down exponents were determined to be 0.044 ± 0.004 and 0.046 ± 0.005 for reactions Fe(CN) 4− 6 + S 2 O 2− 8 and Fe(phen) 2+ 3 + S 2 O 2− 8 , respectively. The values of the critical slowing down exponents showed that only dynamic critical slowing down effect, and no thermodynamic singularity could be observed for the two reactions. K E Y W O R D Scritical slowing down, critical exponent, reaction kinetics 258

show abstract

Critical anomalies of alkaline fading of phenolphthalein in the critical solution of 2-butoxyethanol + water

Cited by 16 publications

References 32 publications

Observation of Unusual Molecular Diffusion Behaviour below the Lower Critical Solution Temperature of Water/2‐Butoxyethanol Mixtures by using Fluorescence Correlation Spectroscopy

Observation of Unusual Molecular Diffusion Behaviour below the Lower Critical Solution Temperature of Water/2‐Butoxyethanol Mixtures by using Fluorescence Correlation Spectroscopy

Theory of First Order Chemical Kinetics at the Critical Point of Solution

Kinetics of two redox reactions in 2‐butoxyethanol and water near its critical point of solution

Contact Info

Product

Resources

About