Chemical Dynamics and Critical Phenomena: Electrical Conductivity and Reactivity of Benzyl Bromide in Triethylamine+Water Near its Consolute Point

Specker, Christopher D.; Ellis, Joel M.; Baird, James K.

doi:10.1007/s10765-007-0234-7

Cited by 17 publications

(9 citation statements)

References 26 publications

(102 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A comparison of Figures and reveals that the familiar zeroth-order rate law persists both inside and outside the critical region. This preservation of kinetic order was noted previously in the case of the pseudo-first-order Menschutkin reaction of benzylbromide with triethylamine near the LCST of triethylamine + water . Taken together, the Menschutkin reaction and the iodination of acetone reaction suggest that reaction mechanisms are unaffected by the presence of the critical point.…”

Section: Discussionsupporting

confidence: 82%

Reaction Kinetics and Critical Phenomena: Iodination of Acetone in Isobutyric Acid + Water near the Consolute Point

Baird

2009

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

The rate of iodination of acetone has been measured as a function of temperature in the binary solvent isobutyric acid (IBA) + water near the upper consolute point. The reaction mixture was prepared by the addition of acetone, iodine, and potassium iodide to IBA + water at its critical composition of 38.8 mass % IBA. The value of the critical temperature determined immediately after mixing was 25.43 degrees C. Aliquots were extracted from the mixture at regular intervals in order to follow the time course of the reaction. After dilution of the aliquot with water to quench the reaction, the concentration of triiodide ion was determined by the measurement of the optical density at a wavelength of 565 nm. These measurements showed that the kinetics were zeroth order. When at the end of 24 h the reaction had come to equilibrium, the critical temperature was determined again and found to be 24.83 degrees C. An Arrhenius plot of the temperature dependence of the observed rate constant, k(obs), was linear over the temperature range 27.00-38.00 degrees C, but between 25.43 and 27.00 degrees C, the values of k(obs) fell below the extrapolation of the Arrhenius line. This behavior is evidence in support of critical slowing down. Our experimental method and results are significant in three ways: (1) In contrast to in situ measurements of optical density, the determination of the optical density of diluted aliquots avoided any interference from critical opalescence. (2) The measured reaction rate exhibited critical slowing down. (3) The rate law was pseudo zeroth order both inside and outside the critical region, indicating that the reaction mechanism was unaffected by the presence of the critical point.

show abstract

Section: Discussionsupporting

confidence: 82%

Reaction Kinetics and Critical Phenomena: Iodination of Acetone in Isobutyric Acid + Water near the Consolute Point

Baird

2009

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

show abstract

“…The solvent power of these liquids permits them to be used to study the effect of the critical point on the net rate of reaction [23][24][25][26][27][28][29][30][31][32][33] and also on the position of chemical equilibrium [11,34,35].…”

Section: Discussionmentioning

confidence: 99%

Chemical Equilibrium and Critical Phenomena: The Solubilities of Iron(III) Oxide and Cobalt(II,III) Oxide in Isobutyric Acid + Water Near the Consolute Point

Baird

2009

Int J Thermophys

Self Cite

View full text Add to dashboard Cite

The solubilities of iron(III) oxide, formula Fe 2 O 3 , and cobalt(II,III) oxide, formula Co 3 O 4 , have been determined in the liquid mixture, isobutyric acid + water, along the critical isopleth at temperatures above the upper critical solution temperature near 299 K. When plotted in van't Hoff form with ln s versus 1/T , the measurements of solubility, s, lie on a straight line for values of the temperature, T , in kelvin, which are sufficiently in excess of the critical solution temperature, T c . The sign of the slope, (∂ ln s/∂(1/T )), indicates that in the case of both oxides, the dissolution reaction is endothermic. When the temperature is within 1 K of T c , however, the slope departs from its constant value and appears to diverge toward negative infinity. The principle of critical-point universality predicts that a divergence in (∂ ln s/∂(1/T )) is to be expected for T near T c in those cases where the stoichiometry of the dissolution reaction involves both components of the solvent; moreover, the Gibbs-Helmholtz equation predicts that, if the heat of solution is endothermic, the sign of the divergence should be negative. Both of these predictions are confirmed by the solubilities of Fe 2 O 3 and Co 3 O 4 measured as a function of temperature along the critical isopleth of isobutyric acid + water.

show abstract

“…The influence of the critical phenomena on chemical reactions has been studied both theoretically and experimentally for several decades. − Although speeding up of the reactions in critical solutions has also been reported, − more reliable experimental observations and the theoretical analysis support the critical slowing down effect of the chemical reactions. ,− This slowing down has been attributed to the thermodynamic or dynamic anomalisms; ,, however, more likely these two factors are coexistent but difficult to be separated. As the thermodynamic effect was considered, a reaction rate was commonly expanded in a Taylor series at its chemical equilibrium, and only the linear term usually was kept to discuss the critical anomalous behavior of the reaction including the critical exponent, reflecting the strength of the critical slowing down of the reactivity.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of the Reaction of Crystal Violet with Hydroxide Ion in the Critical Solution of 2-Butoxyethanol + Water

Mao

Chen

et al. 2013

J. Phys. Chem. A

View full text Add to dashboard Cite

The kinetics of alkaline fading of crystal violet (CV) has been studied by UV spectrophotometry and microcalorimetry in the critical binary solution of 2-butoxyethanol + water at the initial reaction stage and various temperatures. It was found that the first-order rate constants obtained from these two methods are well accorded with each other, and the temperature dependence of the rate constant obeyed the Arrhenius equation in a temperature region far from the critical point. The critical slowing down was detected by both methods near the critical point. A simple empirical crossover model was proposed and used to analyze the experimental data to obtain the critical exponents, which were 0.158 ± 0.013 and 0.133 ± 0.012 from UV spectrophotometry and microcalorimetry, respectively, and the former was in good agreement with the theoretical prediction of 0.151. The slight lower value derived from microcalorimetry was attributed to the stirring in the microcalorimeter, which weakened the critical reduction of the diffusion coefficient.

show abstract

Chemical Dynamics and Critical Phenomena: Electrical Conductivity and Reactivity of Benzyl Bromide in Triethylamine+Water Near its Consolute Point

Cited by 17 publications

References 26 publications

Reaction Kinetics and Critical Phenomena: Iodination of Acetone in Isobutyric Acid + Water near the Consolute Point

Reaction Kinetics and Critical Phenomena: Iodination of Acetone in Isobutyric Acid + Water near the Consolute Point

Chemical Equilibrium and Critical Phenomena: The Solubilities of Iron(III) Oxide and Cobalt(II,III) Oxide in Isobutyric Acid + Water Near the Consolute Point

Kinetics of the Reaction of Crystal Violet with Hydroxide Ion in the Critical Solution of 2-Butoxyethanol + Water

Contact Info

Product

Resources

About