Water-dimethyl Sulfoxide Mixtures Research Articles

Hydrogen-1 and carbon-13 nuclear magnetic resonance investigation of nicotinic acid, its anion, and cation, in water and water-dimethyl sulfoxide mixtures. Influence of dimethyl sulfoxide on relative acidities

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrogen-1 and carbon-13 nuclear magnetic resonance investigation of nicotinic acid, its anion, and cation, in water and water-dimethyl sulfoxide mixtures. Influence of dimethyl sulfoxide on relative aciditiesTauqir Khan, Jean Claude Halle, Marie Paule Simonnin, and Robert SchaalCite this: J. Phys. Chem. 1977, 81, 6, 587–590Publication Date (Print):March 1, 1977Publication History Published online1 May 2002Published inissue 1 March 1977https://doi.org/10.1021/j100521a019RIGHTS & PERMISSIONSArticle Views75Altmetric-Citations14LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (523 KB) Get e-Alerts

Transfer-free Energy Aspect on the Keto-enol Tautomerization Rate of Benzoylacetone in Water-Dimethyl Sulfoxide Mixtures

Abstract The transfer-free energies of the keto form, the enol form, and the transition state of benzoylacetone from water to water–dimethyl sulfoxide (DMSO) mixtures have been evaluated on the basis of kinetic and partition experiments at 25 °C. The results were compared with those of acetylacetone, and the substituent effects of methyl and phenyl groups on the transfer-free energies have been discussed in terms of the group transfer-free energy.

A J-2 acidity function for solutions of sodium hydroxide in water-ethanol and water-dimethyl sulfoxide mixtures

A J-2 acidity function for solutions of sodium hydroxide in water-ethanol and water-dimethyl sulfoxide mixtures

Hydrogen exchange studies. X. Base-catalyzed isotopic exchange of molecular hydrogen. III. Transition-state vs. initial-state solvation in the dimethyl sulfoxide-water system

The kinetics of isotopic exchange between D$sub 2$ and H$sub 2$O under catalysis by OH$sup -$ have been determined in dimethyl sulfoxide-water mixtures as a function of temperature. Activation parameters have been derived. It is found that $delta$ enthalpy decreases by 7 kcal/mole over the range 0 to 50 mole percent Me$sub 2$SO and then rises slightly. $delta$ entropy passes through a minimum near 60 mole percent Me$sub 2$SO. As a result $delta$ free energy decreases only moderately (3.5 kcal/mole) over the full range of medium composition. Transition-state enthalpies of transfer, delta $delta$H/sub tr//sup t/, from water to aqueous Me$sub 2$SO, have been evaluated using the enthalpies of activation and the known enthalpies of transfer of OH$sup -$ and D$sub 2$. The delta $delta$H/sub tr//sup t/ term is endothermic throughout the range of solvent composition; for 96.9 mole percent Me$sub 2$SO, delta $delta$H/sub tr// sup t/ is 13.7 kcal/mole compared with a value of 17.5 kcal/mole for hydroxide ion. This points to a transition-state structure with considerable charge localization on oxygen, resulting in transition-state desolvation in Me$sub 2$SO- rich media. This conclusion allows certain mechanisms for the D$sub 2$--OH$sup - $ exchange to be excluded. Currently favored is a mechanismmore » in which an H$sub 2$O molecule participates in the rate-determining step, providing electrophilic assistance for removal of D$sup -$ during attack by HO$sup -$ on D$sub 2$, and one involving rate-determining replacement of an H$sub 2$O of solvation from hydroxide ion by D$sub 2$ followed by rapid isotopic exchange. (auth)« less

Keto-enol tautomerization rates of acetylacetone in water-acetonitrile and water-dimethyl sulfoxide mixtures: Rate-partition relationship

The rate of the keto-enol tautomerization of acetylacetone was studied in water-acetonitrile (AN) and water-dimethyl sulfoxide (DMSO) mixtures. The apparent partition coefficients of acetylacetone between n-heptane and these mixed solvents were measured to estimate the free energies of transfer of each tautomer from water to the mixed solvents. The rate constants of enolization and ketonization depended remarkably on the composition of the mixed solvents, and a maximum in the enolization reaction was observed at about 20 mol% DMSO in water-DMSO mixtures. These kinetic solvent effects were analyzed with “rate-partition relationship” (RPR) derived on the basis of the transfer free energy concept, and the unusual kinetic solvent effect observed in water-DMSO mixtures was interpreted in terms of the destabilization of the keto form in the mixed solvents. An applicability of the RPR to other reactions was suggested.

Kinetics study of selective solvation of electrons in water-dimethyl sulfoxide mixtures

Dimethyl sulfoxide (DMSO) is known to solvate with difficulty anions including the electron and hence the addition of DMSO to a medium increases the anionic reaction rates. An attempt was made to study this effect in mixtures of H$sub 2$O--DMSO for specific reactions of the solvated electron using the pulse radiolysis technique. To begin with we chose different solutes among those known as good scavengers of electrons, neutral ones, N$sub 2$O, and positive and negative ionic ones (NO$sub 3$$sup -$ and H$sup +$). The experiments were carried out with a Febetron delivering 10-nsec pulses of 1.8-MeV electrons. The rate of disappearance of the solvated electron formed by the pulse was measured by direct observation of the decay absorption at 870 or 600 nm. The ultrapure products were used as supplied except for DMSO which was distilled before use. (auth)

Volumes and Heat Capacities of Dimethylsulfoxide, Acetone, and Acetamide in Water and of some Electrolytes in these Mixed Aqueous Solvents

The densities and volumetric specific heats of binary mixtures of dimethylsulfoxide (DMSO), acetone (ACT), and acetamide (ACM) in water were measured at 25 °C with a flow densimeter and a flow microcalorimeter. The same properties were also determined for ternary mixtures of 0.1 m LiCl, NaCl, Me4NBr, and Bu4NBr in ACT–water and DMSO–water mixtures, and volumes for 0.1 m Bu4NBr in ACM–water and urea–water mixtures. The derived apparent molal volumes and heat capacities of nonelectrolytes in water and the transfer functions of the electrolytes from water to the mixed solvents suggest that, contrary to urea, the present non-electrolytes are slightly hydrophobic but, with the possible exception of ACT, their overall influence on water structure has practically no influence on the various solute–solute interactions.

Ionization enthalpy of benzoic acid in water—dimethylsulfoxide mixtures

The ionization enthalpy of benzoic acid has been measured calorimetrically at 25°C in H 2ODMSO mixtures ranging from pure water to a maximum DMSO molar ratio X DMSO = 0.80. With the increase of DMSO content, the ionization becomes more and more endothermic, and for X DMSO = 0.8 the ionization enthalpy is about 6 kcal mol −1 higher than in water. By also measuring the solution enthalpy of crystalline benzoic acid in the mixtures, it has been shown that the solvation of the undissociated molecule is the main cause for the increase of the dissociation enthalpy. A comparison has been made between the relative enthalpies of benzoic and hydroxide ions in H 2ODMSO mixtures.

Potentiometric Determination of the Autoprotolysis Constants of Water–Dimethylsulfoxide Mixtures at Different Temperatures and Related Thermodynamic Quantities

Potentiometric Determination of the Autoprotolysis Constants of Water–Dimethylsulfoxide Mixtures at Different Temperatures and Related Thermodynamic Quantities

Calorimetric measurement of the water ionization enthalpy in dimethylsulfoxide—water mixtures at 25°C

The Δ H ion of the process 2H 2O x → H 3O + x + OH - x has been calorimetrically measured in dimethylsulfoxide (DMSO)—water solutions for X DMSO molar ratios ranging between 0 and 0.8 at T = 25°C. The Δ H ion values show a well-pronounced minimum at X DMSO = 0.5, for which composition the ionization reaction is 4.28 kcal/mole less endothermic than in pure water. The combination of the Δ H ion data with the existing p K a/1 values reveals several features of DMSO—water mixtures with regard to the ionic solvating power and the mixed solvent structure.

Hydrogen exchange studies. VII. Isotopic exchange of molecular hydrogen in dimethyl sulfoxide-water mixtures under base cataysis

Hydrogen exchange studies. VII. Isotopic exchange of molecular hydrogen in dimethyl sulfoxide-water mixtures under base cataysis

Iron (II) and iron (III) isotope exchange in water–dimethyl sulfoxide mixtures

AbstractThe rate of the isotope exchange reaction between iron(II) and iron(III) perchlorates has been measured in a solvent mixture containing a 3:2 mole ratio of water to dimethyl sulfoxide over the temperature range from 25° to −98°C. In this temperature range, the reactants can diffuse together faster than they can undergo isotope exchange. The activation enthalpy and entropy for the acid‐independent reaction were 6.0 ± 1.2 kcal/mole and −38 ± 17 cal/deg mole, respectively. Below −22°C, the acid‐dependent exchange reaction did not contribute significantly to the exchange. In liquid media at −112° and −117°C and in a solid glass at −136°C, no isotope exchange was observed over the period of a calculated half‐life for the reaction. At these temperatures, the rate at which the reactants diffuse together is slower than the calculated rate of isotope exchange. In a solid glass at −196°C, no isotope exchange was observed over the period of one week.

Solvent effects in the substitution reactions of trans-Pt(C 5H 5N) 2Cl 2

The rates of nucleophilic substitution in trans-Pt(C 5H 5N) 2Cl 2 were determined as a function of solvent composition in dimethylsulfoxide (DMSO) and dimethylsulfoxide-water mixture. The results of these measurements combined with an investigation of solvent isotope effect suggest that leaving group solvation, or some similar process involving hydrogen bonding, plays a kinetically important role in these reactions. For example, the second-order rate constants for thiourea as a nucleophile are 0·64, 0·71, and 0·991. mole −1 sec −1 in DMSO and DMSOD 2O or DMSOH 2O containing 0·18 mole fraction of the aqueous component respectively.

Viscosity and local liquid structure in dimethyl sulfoxide-water mixtures

Viscosity and local liquid structure in dimethyl sulfoxide-water mixtures

The isothermal compressibility of dimethylsulfoxide–water mixtures at 35 °C

The isothermal compressibility of a series of dimethylsulfoxide–water mixtures passes through a minimum near 0.4 mole fraction dimethylsulfoxide. This behavior is compared with that of other aqueous binaries and provides further evidence of specific hydrogen bonded complexes in the dimethylsulfoxide–water system.

Proton exchange between guanidinium ion and water in water-dimethyl sulfoxide mixtures

Proton exchange between guanidinium ion and water in water-dimethyl sulfoxide mixtures

Solubility and complex formation equilibria of silver chloride in dimethyl sulfoxide-water mixtures

Solubility and complex formation equilibria of silver chloride in dimethyl sulfoxide-water mixtures

A proton magnetic resonance solvation study of aluminum chloride in dimethylsulfoxide-water mixtures

A proton magnetic resonance solvation study of aluminum chloride in dimethylsulfoxide-water mixtures

Amylose-Iodine Complex. IV. The Complex in Dimethyl Sulfoxide-Water Mixtures

Abstract The temperature at which the blue color due to the formation of amylose-iodine complex fades completely has been determined with a system of amylose and iodine dissolved in dimethyl sulfoxide-water mixtures. This temperature rises with the increase in the concentration of iodine in mixtures, and also with the increasing concentration of water in the mixed solvents. The spectrophotometric results show that the nature of the amylose-iodine complex in a dimethyl sulfoxide-water mixture is similar to that of one in water, and that the triiodide ion or a chemical species similar to the ion, i.e., the polyiodide ion, contributes to the formation of the complex. The viscometric studies show that the amylose molecule takes a deformed helix conformation prior to the formation of the blue iodine complex and that this conformational prerequisite to the complex formation is fulfilled when the water concentration in a dimethyl sulfoxide-water mixture exceeds a critical value. These results stated above may indicate that the triiodide (polyiodide) ion plays the part of “stabilizer” for the fixation of iodine molecules within the helically-wound chain of the amylose molecule when the amylose exists primarily as a deformed helix in solution.