The thermodynamic characteristics of dissolution and solvation of cetyltrimethylammonium perchlorate in the water-propan-2-ol system

The solubility of cetyltrimethylammonium perchlorate (CTAP) in propan-2-ol and its mixtures with water was determined by the isothermal saturation method over the whole composition range at 278.15–308.15 K. The solubility products and total standard Gibbs energies of transfer of the n-C₁₆H₃₃N(CH₃) ₃ ⁺ and ClO ₄ ^? ions were calculated. The solubility of CTAP in the mixed solvent specified was substantially influenced by solvophilic effects and the heterosolvation of ions caused by them.     

Effect of solvent on the kinetics of arylsulfonylation of N-alkylated anilines in a water-propan-2-ol system

The effect of the composition of a water-propan-2-ol solvent on the kinetics of arylsulfonylation of N-ethyl-, N-isopropyl-, and N-butylanilines with 3-nitrobenzenesulfonyl chloride at 298 K was studied. The reaction rate constant increases monotonically with an increase in the water fraction in the solvent from 5 to 30 wt.%. The apparent activation parameters of the reaction of N-butylaniline with 3-nitrobenzenesulfonyl chloride were calculated. No considerable changes in the activation parameters of the reaction were observed on going from pure propan-2-ol to a 10% aqueous solution, which indicates that the mechanism remains unchanged upon solvent change. Propan-2-ol with a water content of 5–30 wt.% can be used in the synthesis of arylsulfonylation products of the amines under study in 98–99% yield. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 937–939, June, 2006.     

Kinetics of the solvolysis of a cationic and of an anionic chloro-cobalt(III) complex in water-propan-1-ol mixtures

Summary The kinetics of the solvolysis of the ions [Co(NH₃)₅Cl]²⁺ and [Co(CN)₅Cl]^3– have been investigated in a range of water-rich mixtures of water with n-PrOH at various temperatures. The variation of the enthalpies and entropies of activation with solvent composition show extrema in composition ranges where the physical properties of the mixtures, influenced by changes in solvent structure, also show extrema. From the application of a free energy cycle to the process of the initial state going to the transition state, it is concluded for the solvolyses of both complexes that the species of Co^III in the transition state is more stable in water + n-PrOH mixtures than the ionic complexes of Co^III in the initial state. The results are compared with those for the solvolysis of these and related complexes in mixtures of water with other alcohols.     

Kinetics and mechanism of radiation telomerization of tetrafluoroethylene in hexafluoropropan-2-ol and trifluoroethanol

The kinetics of radiation telomerization of tetrafluoroethylene (TFE) in trifluoroethanol and hexafluoropropan-2-ol (HFIP) has been investigated by method of kinetic calorimetry. The nature of active centers initiating the process of telomerization of tetrafluoroethylene in hexafluoroisopropanol in the temperature range of 77—300 K was investigated by ESR spectroscopy. The molecular structure and properties of the obtained telomeres were studied by IR spectroscopy and TGA.     

CO2 laser-induced decomposition of propan-2-ol,butan-2-ol,pentan-2-ol,pentan-3-ol,and hexan-2-ol

The pulsed CO₂ laser-induced decompositions of propan-2-ol, butan-2-ol, pentan-2-ol, pentan-3-ol, and hexan-2-ol in the gas phase have been investigated. Like ethanol which we examined previously [1] the absorption cross section of propan-2-ol for pulsed 9R14 radiation increases with pressure at low pressures, an effect attributed to rotational hole-filling. In contrast the absorption cross section of butan-2-ol (10R24) has only a small pressure dependence and those of pentan-2-ol (9R26), pentan-3-ol (10R14), and hexan-2-ol (9P20) show little or no variation with pressure in the range 0.1–5.0 torr. Decomposition products have been investigated at low pressure where the excitation of the alkanols was essentially collision free. The observed products for all the alkanols can be rationalized on the basis of primary dehydration and C? C fission channels, with minor contributions from other molecular eliminations. © 1994 John Wiley & Sons, Inc.     

Kinetics and Mechanism of the Oxidation of Propan-1-ol and Propan-2-ol by Permanganate in the Absence and Presence of Tween-20 in Perchloric Acid Medium

The kinetics of the oxidation of propan-1-ol and propan-2-ol by KMnO₄ in HClO₄ medium has been studied in absence and presence of Tween-20. In the absence of Tween-20 the reaction is of first order with respect to each of permanganate and H⁺, but of complex order with respect to substrate. The active oxidant species HMnO₄ reacts with the alkanol molecule to form an intermediate complex, which decomposes in the rate-determining step to form the respective product and Mn^v. In the presence of Tween-20, both the oxidant and the substrate are distributed between the aqueous phase and the micellar pseudo-phase and then react. Different kinetic and thermodynamic parameters have been evaluated. Compensation between water structure destruction and substrate–micelle interaction plays an important role in the presence of the surfactant.     

Effect of physicochemical properties of water-propane-2-ol mixture and temperature on thermodynamics of Cu complexation with glycine

The stability constants of Cu²⁺ complexes with glycine are determined by potentiometric method in water-propane-2-ol mixture, i.e., [CuL]⁺, CuL₂ (L = Gly^–) (0.070, 0.167, 0.310 mole fraction of alcohol), and [CuHL]²⁺ (0.070 mole fraction of alcohol) at 298.15, 308.15, and 318.15 K. Thermodynamic characteristics of Cu²⁺ complexation with glycine and the Gibbs energy of transfer of complex species [CuL]⁺ and CuL₂ from water to a mixed solvent are calculated. The solvation-thermodynamic analysis of effects of water-propane-2-ol solvents and of separate solvation contributions of reagents to Cu²⁺ coordination with glycine is performed. The increasing stability of the [CuL]⁺ and CuL₂ complexes in water-propane-2-ol as compared to that in pure water is explained by the increasing energy of solvation of complex species [CuL]⁺ and CuL₂ and by the decreasing energy of solvation of Cu²⁺ and Gly^– ions.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 4, 2005, pp. 311–318.Original Russian Text Copyright © 2005 by Tsurko, Bondarev, Shikhova, Khrebto.     

Kinetics and mechanism of the oxidation of glycine by N-bromosuccinimide

A systematic kinetic study on the oxidation of glycine by N-bromosuccinimide (NBS) in presence of mercuric acetate in acetic acid—water media has been made. Near first order dependence inNBS and glycine and near inverse first order dependence in hydrogen ion concentrations have been observed. A negligible ionic strength effect and a positive dielectric effect have been observed. Various rate parameters have been computed and hydrocyanic acid identified as the end product. On the basis of the kinetic data, a mechanism of the reaction has been proposed.With 3 Figures     

Viscosity of aqueous solutions of 2-propyne-1-ol, 2-methyl-3-butyne-2-ol and 3-butene-2-ol

Viscosities of aqueous solutions of 2-propyne-1-ol (propargyl alcohol), 2-methyl-3-butyne-2-ol and 3-butene-2-ol have been measured at temperatures 308.15, 313.15, 318.15, 323.15 and 328.15?K over the entire composition range. Viscosity of the aqueous solutions of 2-methyl-3-butyne-2-ol and 3-butene-2-ol increases up to a maximum value and then starts decreasing almost linearly as the mole fraction of alcohol increases. 2-Methyl-3-butyne-2-ol + water and 3-butene-2-ol + water systems exhibit maxima around 0.5 and 0.2 mole fraction, respectively. Conversely, 2-propyne-1-ol + water system shows a rapid initial increase in viscosity up to 0.3 mole fraction followed by a slow steady increase as the mole fraction of alcohol increases to its pure state. Plots of excess viscosities against mole fraction of organic solutes for all the systems exhibit a sharp increase in η ^E to reach a well defined maxima, after which the curves show a descending trend. The variations of viscosity and excess viscosity with the composition of the mixtures have been interpreted in terms of hydrophobic and hydrophilic interactions between the species forming the mixtures.     

Kinetics of oxidation of glycine by aqueous chlorine

The kinetics of oxidation of glycine with aqueous chlorine has been investigated. The reaction is first order with respect to both molecular chlorine and glycine and inverse first order with respect to H⁺. The effect of various factors on the initial rate has also been studied. The kinetic parameters have been calculated and a possible mechanism is proposed.

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Catalytic properties of a mixed calcium-cobalt orthophosphate, I. Kinetics of propan-2-ol dehydrogenation

Kinetics of dehydrogenation of propan-2-ol on the most active catalyst found in the mixed calcium-cobalt orthophosphate system, Ca_3-xCo_x(PO₄)₂, with x=0.32, has been studied. The activation energy of the reaction was also determined.     

Kinetics and mechanism of the hydration of the equilibrium mixture of 3-methyl-1-buten-3-ol and 3-methyl-2-buten-1-ol with isoprene in aqueous solutions of sulfuric acid

The kinetic relationships of the hydration of an equilibrium mixture of 3-methyl-1-buten-3-ol (dimethylvinylcarbinol, DMVC) and 3-methyl-2-buten-1-ol (dimethylallyl alcohol, DMAA) with isoprene (C₅H₈) were investigated in aqueous solutions of sulfuric acid from 24.9 to 49.7% at 25°C. Data were obtained on the mechanism of hydration of the equilibrium mixture of DMVC and DMAA with isoprene.Deceased.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1311–1314, June, 1992.     

Vapor-Liquid Equilibria for Chlorobenzene with Butan-1-ol, 2-Methylpropan-1-ol and 2-Methylpropan-2-ol at 94.6 kPa

Abstract

Vapor-liquid equilibria at 94.6 kPa, over the entire composition range were measured for three binary systems - butan-1-ol(1) + chlorobenzene(2), 2-methylpropan-1-ol(1) + chlorobenzene(2), 2-methylpropan-2-ol(1) + chlorobenzene(2)- using a Swietoslawski type ebulliometer. The composition (x ₁) vs. temperature (T) data were found to be well represented by Wilson model.     

Kinetics of catalytic hydrogenation of 4-nitroaniline in aqueous solutions of propan-2-ol with acid or base additives

The effect of addition of acetic acid and sodium hydroxide to an aqueous azeotropic solution of propan-2-ol on the rate of 4-nitroaniline hydrogenation is studied. The base additive accelerates the apparent rate of nitro group reduction, while the presence of acetic acid slows the reaction rate. It is experimentally established that the rate of nitro group conversion calculated from the amount of reacted 4-nitroaniline exceeds the rate of hydrogen uptake from the gas phase in all of the studied solvents. Hydrogen bound by active sites of the catalyst surface is found to participate notably in the reactions. It is proved both experimentally and theoretically that strongly bound atomic forms of adsorbed hydrogen are most active in the reduction of the nitro group.