Determination of absolute transfer free energies of hydroxyl ion from water to aqueous 2-methoxy ethanol

Bhattacharya, Abhijit; Das, Asim K.; Kundu, Kiron K.

doi:10.1139/v81-169

Cited by 9 publications

(6 citation statements)

References 11 publications

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“…2, with an increase in the content of 2‐propanol the rate constant of the reaction increases. Alcohols have a lower dielectric constant than water, and according to Hughes–Ingold rules for solvent effects in nucleophilic substitution reactions 21–23, formation of the neutral carbinol base from two oppositely charged reactants in aqueous mixtures of alcohols is more favorable in higher weight percentages of alcohols 24–26 and similar results are observed in this work.…”

Section: Resultssupporting

confidence: 86%

Kinetics of malachite green fading in water–ethanol–2‐propanol ternary mixtures

Samiey

Motamedi

2011

Int J of Chemical Kinetics

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The rate constant of malachite green (MG + ) alkaline fading was measured in waterethanol-2-propanol ternary mixtures. This reaction was studied under pseudo-first-order conditions at 283-303 K. It was observed that the observed reaction rate constants, k obs , were increased in the presence of different weight percentages of ethanol and 2-propanol. The fundamental rate constants of MG + fading in these solutions were obtained by using the SESMOR-TAC model. In each series of experiments, the concentration of one alcohol was kept constant and the concentration of the second one was changed. It was observed that at the constant concentration of one alcohol and variable concentrations of the second one, with an increase in temperature, k 2 values decrease according to the trend of hydroxide ion nucleophilic parameter values and k 1 values increase. C

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Section: Resultssupporting

confidence: 86%

Kinetics of malachite green fading in water–ethanol–2‐propanol ternary mixtures

Samiey

Motamedi

2011

Int J of Chemical Kinetics

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“…bp, density, and refractive index, compared fairly well with those giver! in the literature (6,11,12). The solvents so purified were stored in a desiccator not more than 10 days and redistilled every timz before use after refluxing with Na for some time.…”

Section: Introductionmentioning

confidence: 99%

Free energies and entropies of transfer of hydrogen halides from water to aqueous solutions of tetrahydrofuran, dioxane, and 1,2-dimethoxyethane and the structuredness of the solvents

Datta¹,

Kundu²

1981

Can. J. Chem.

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JAYATI DATTA and KIRON K. KUUDU. Can. J. Chem. 59. 3149 (1981). Standard free energies (AG,O) and entropies (AS:) of transfer of hydrogen iodide from water to some aqueous solutions of tetrahydrofuran (THF), dioxane (D), and 1,2-dimethoxyethane (DME) have been determined by measuring the emf's of the cell: Pt. H, (g, 1 atm);KOH (in,), KI (in,). solventAgI, Ag at seven equidistant temperatures ranging from 5 to 3YC. In each of these ethereal solvent systems AG,O values of HI, as well as of HCI and HBr obtained from the literature, and particularly of the individual ions, suggest that while H+ is increasingly stabilized, halide ions are increasingly destabilized due to the influence of cosolvent-induced larger "basicity" and smaller "acidity" of the mixed solvents compared to that of water, and both conformed to the expected order: D < THF < DME. Moreover, the relative order: C1-> Br-> I-in all the solvent systems is ascribable to the combined effects of "acid-base" and "soft-soft" interactions and the superimposed quadrupolar interactions in the case of D and the charge transfer to solvent (CTTS) complexation effect, especially on I in the case of THF. Analysis of the entropic contributions, TAStO, and particularly of the relative order of A Y (= TASto (H') + TASP,, (X-))for X = CI, Br. and I, in the light of the semi-quantitative theory proposed earlier by Kundu e t a / . . reveals that at initial compositions, while T H F promotes 3D structures of water. both D and DME break down the same; at higher compositions all the cosolvents disrupt the structure as usual due to packing imbalance. The nature and relative positions of AY-composition profiles also suggest that while increase of hydrophobic groups of the cosolvents increases the stabilization, increase in hydrophilicity or H-bonding sites decreases the stabilization of the 3D structure of water.

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“…Alcohols have a lower dielectric constant than water and according to Hughes–Ingold rules for solvent effects in nucleophilic substitution reactions 20–22, formation of the neutral carbinol base from two oppositely charged reactants is more favorable in higher weight percentages of alcohols. Confirming this result, it has been found the rate constant of crystal violet (CV + ) fading decreases in urea–water mixtures where the dielectric constant increases 23 and increases in the presence of cosolvents such as ethylene glycol, 1,2‐propanediol, ethanol 5, 2‐methoxy ethanol 24, and tetrahydrofuran 25. On the other hand, the reaction rate of bromophenol blue (BPB = ) fading, which forms charged product, decreases with an increase in the weight percentage of alcohol in a series of alcohol–water mixtures 16,26.…”

Section: Resultsmentioning

confidence: 63%

Kinetics of malachite green fading in alcohol–water binary mixtures

Samiey

Toosi

2010

Int J of Chemical Kinetics

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The rate constant of alkaline fading of malachite green (MG + ) was studied in alcohol-water binary mixtures. This reaction was studied under pseudo-first-order conditions at 283-303 K. It was observed that the reaction rate constants were increased in the presence of different weight percentages of methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, 1,2-propanediol, and glycerol (up to 19.3%). In aqueous glycerol solutions higher than 19.3%, the rate constant of reaction slightly decreases, which is due to high viscosity values of solvent mixtures. The fundamental rate constants of MG + fading in these solutions were obtained by using the SESMORTAC model. Owing to the charged character of activated complex, with an increase in the weight percentage of the used cosolvents or temperature, k 2 values change according to the trend of hydroxide ion nucleophilic parameter values. Also, using MG + solvatochromism, a simple test, called MAGUS, is introduced for measuring the glycerol concentration in its aqueous solutions. C 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: [508][509][510][511][512][513][514][515][516][517][518] 2010

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Determination of absolute transfer free energies of hydroxyl ion from water to aqueous 2-methoxy ethanol

Cited by 9 publications

References 11 publications

Kinetics of malachite green fading in water–ethanol–2‐propanol ternary mixtures

Kinetics of malachite green fading in water–ethanol–2‐propanol ternary mixtures

Free energies and entropies of transfer of hydrogen halides from water to aqueous solutions of tetrahydrofuran, dioxane, and 1,2-dimethoxyethane and the structuredness of the solvents

Kinetics of malachite green fading in alcohol–water binary mixtures

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