Concentrated salt effects on solvolysis rates in 1,4-dioxane–H2O mixed solvent and the expansion of the use of the Hammett equation for salt effects

Hojo, Masashi; Ueda, Tadaharu; Inoue, Sunao; Kawahara, Yoshihiro

doi:10.1039/b001034k

Cited by 24 publications

(10 citation statements)

References 48 publications

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“…10 Our model for water containing highly concentrated salts has been supported by the Raman spectra of D2O containing concentrated Et4NBr. With this model, concentrated salt effects on the solvolysis rates of aliphatic halides and related compounds (RX) in organic solvent-water mixed media, such as methanol-H2O, 9 acetone-H2O, 11 1,4-dioxane-H2O, 10 and acetonitrile-H2O, 12 have been successfully elucidated. In addition, an expansion of the use of the Hammett equation for salt effects has been proposed.…”

Section: Isolated Molecules Of H2o Are Very Different From Bulk Watermentioning

confidence: 99%

“…We have reported that the Raman peak at 2500 -2510 cm -1 is developed by concentrated Et4NBr in D2O. 10 The difference in the peak wavelength between 2510 and 2530 cm -1 , which are observed in Et4NBr and LiBr solutions, respectively, must be caused by the difference in the effect of the cation solvation, Et4N + and Li + . The above Raman spectra have demonstrated that the hydrogen-bonded structure of bulk D2O is destroyed by the concentrated salts; the same argument should also be justified for H2O solutions.…”

Section: Formation Of [Cox4] 2-in Ordinary Solutions and The Cause Ofmentioning

confidence: 99%

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Effects of Electrolytes on the Configuration Change of Cobalt(II)-Halide Complexes in Chloroform/Water Reverse Micelle Systems

et al. 2001

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As nanometer-size water droplets or "water pools," relatively large amounts of water can be stabilized in nonpolar organic solvents by a variety of surfactants; this kind of micelle system is called a reversed or reverse micelle. 1 The size of the "water pool" may vary from ~1 nm to ~10 nm, as a linear function of the W value, where W = [H2O]/[surfactant]. 1,2 The "water pools" provide very specific reaction fields; many studies have demonstrated that the water in "water pool" in reverse micelles considerably differs from that of normal water. 1,3 The extraction of proteins using reverse micelles has received great attention in the field of bioseparation. 4 At W > 12, the character of the water in the "water pool" remains that of normal water. However, at W < 6, almost all water molecules may lose their character as bulk water; 3b such water has been regarded as bound water.Recently, Shervani and Ikushima 5 demonstrated that the ET(30) value in the core region of water/AOT/SC ethane micelles at W = 1.0 corresponds to that in pure ethanol (ET(30) = 51.9, cf. 63.1 for bulk water), 6 where AOT represents the sodium salt of bis(2-ethylhexyl)-2-sulfosuccinate and SC ethane means supercritical ethane.Shirota and Horie 7 have investigated the solvation dynamics of nonaqueous (methanol and acetonitrile instead of H2O) reverse micelles. The solvation dynamics of methanol in reverse micelles depended strongly on the ratio of w; however, the solvation dynamics of acetonitrile in reverse micelles was independent of w, where w = [polar solvent]/[AOT]. They concluded that the different features of the solvation dynamics would be attributed to the role of the hydrogen bonds in methanol and its absence in acetonitrile. The neutron scattering data for the (water + NaCl)/AOT/heptane system have appeared to show that the droplet size is increased by the presence of an electrolyte. 8 We have proposed a model for water containing highly concentrated salts. 9 In a highly concentrated salt solution (≥ 5 mol dm -3 ), too many ions are present to be fully solvated by H2O molecules. Under such extreme conditions, the network by hydrogen bonding of the solvent may almost be destroyed. Isolated molecules of H2O are very different from bulk water (H-O-H); they could behave just as an "alcohol" ([R](H)-O-H), or even as "dihydrogen ether" ([R](H)-O-(H)[R]).10 Our model for water containing highly concentrated salts has been supported by the Raman spectra of D2O containing concentrated Et4NBr. With this model, concentrated salt effects on the solvolysis rates of aliphatic halides and related compounds (RX) in organic solvent-water mixed media, such as methanol-H2O, 9 acetone-H2O, 11 1,4-dioxane-H2O, 10 and acetonitrile-H2O, 12 have been successfully elucidated. In addition, an expansion of the use of the Hammett equation for salt effects has been proposed. 10On the other hand, we have conclusively

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Section: Isolated Molecules Of H2o Are Very Different From Bulk Watermentioning

confidence: 99%

Section: Formation Of [Cox4] 2-in Ordinary Solutions and The Cause Ofmentioning

confidence: 99%

Effects of Electrolytes on the Configuration Change of Cobalt(II)-Halide Complexes in Chloroform/Water Reverse Micelle Systems

et al. 2001

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“…We have proposed that the properties of the residual amount water in (aprotic) organic solvents should resemble to an ether [11,23], and we have termed it "dihydrogen ether" [24][25][26]. Through hydrogen bonding, however, the water molecules may interact with protic solvents, such as MeOH.…”

Section: In the Binary Solvents Of Mecn-meoh And Meoh-h 2 Omentioning

confidence: 97%

Specific coordination phenomena of alkaline earth metal ions with aromatic sulfonate ions in alcohols and binary solvents of acetonitrile–alcohols

Chen

Ayabe

Hojo

et al. 2014

Journal of Molecular Liquids

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“…Several factors potentially contribute to the changes in the hydrolysis rates. These includes the changes in “normal” water structure , the increase in the hydroxide ion (OH − ) activity , and coordination interaction between alkali metal or alkaline earth metal ions and the anion left from a substrate in the “modified” reaction media .…”

Section: Introductionmentioning

confidence: 99%

Influences of Micelle Formation and Added Salts on the Hydrolysis Reaction Rate of p‐Nitrophenyl Benzoate in Aqueous Buffered Media

Bayissa

Ohmae

Hojo

2016

Int J of Chemical Kinetics

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The hydrolysis reaction rate of p-nitrophenyl benzoate (p-NPB) has been examined in aqueous buffer media of pH 9.18, containing surfactants, cetyltrimethylammonium bromide (CTAB) and chloride (CTAC), or sodium dodecyl sulfate (SDS) at 35°C. Although the rate constant [log (k/s −1 )] of p-NPB hydrolysis has once decreased slightly below the critical micelle concentration (CMC) value for CTAB and CTAC, it has begun to increase drastically with micellar formation. With increasing concentrations larger than the CMC value, the log (k/s −1 ) value has reached the optimal value, i.e., a 140-and 200-fold rate acceleration for CTAB and CTAC, respectively, compared to that without a surfactant. Whereas the anionic surfactant, SDS, has caused only a gradual rate deceleration in the whole concentration range (up to 0.03 mol dm −3 ). Increases in pH of the buffer have resulted in increases of the hydrolysis rate. In the CTAB micellar solution, the remarkably enhanced rate has been retarded significantly by the addition of only 0.10 mol dm −3 bromide salts. The effects of rate retardation caused by the added salts follows in the order of NaBr > Me 4 NBr > Et 4 NBr > Pr 4 NBr > n-Bu 4 NBr. In the absence of surfactant, however, the addition of the bromide salts has accelerated the hydrolysis rate, except for the metallic salt of NaBr, with the order of Me 4 NBr < Et 4 NBr < Pr 4 NBr < n-Bu 4 NBr. In the CTAC micellar solution, similar rate retardation effects have been observed in the presence of chloride salts (NaCl, Et 4 NCl, and n-Bu 4 NCl). The effects of added salts have

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Concentrated salt effects on solvolysis rates in 1,4-dioxane–H2O mixed solvent and the expansion of the use of the Hammett equation for salt effects

Cited by 24 publications

References 48 publications

Effects of Electrolytes on the Configuration Change of Cobalt(II)-Halide Complexes in Chloroform/Water Reverse Micelle Systems

Effects of Electrolytes on the Configuration Change of Cobalt(II)-Halide Complexes in Chloroform/Water Reverse Micelle Systems

Specific coordination phenomena of alkaline earth metal ions with aromatic sulfonate ions in alcohols and binary solvents of acetonitrile–alcohols

Influences of Micelle Formation and Added Salts on the Hydrolysis Reaction Rate of p‐Nitrophenyl Benzoate in Aqueous Buffered Media

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