Kinetics and mechanism of triphenylphosphine quarternization with unsaturated carboxylic acids in the medium of acetic acid

Kinetics of reaction of triphenylphosphine with a series of unsaturated carboxylic acids and related esters in the medium of acetic acid as well as in mixtures of acetic acid and acetonitrile was studied by spectrophotometry. The data obtained show that the process of quarternization should be described by kinetic equation of third order, the proton transfer occurs from the solvent. A stepwise mechanism of interaction including formation of prereaction complex on the reaction pathway is proposed. © 2009 Pleiades Publishing, Ltd

Thermochemistry of heteroatomic compounds. Part 5. Enthalpies of vaporization and solvation of tetracoordinated phosphorous derivatives

The enthalpies of vaporization of different classes of tetracoordinated phosphorous compounds have been determined according to their enthalpies of solution in hexane and carbon tetrachloride. Good agreement of some values with literature data is established. The enthalpies of specific (hydrogen bond) interaction of derivatives having acid properties, with p-xylene, dioxan and acetone have been determined. The enthalpies of solvation of cyclic and acyclic derivatives of methylphosphonic acid in different solvents are analysed and discussed. © 1994

Kinetics and Mechanism of the Kabachnik-Fields Reaction: IV. Salicyaldehyde in the Kabachnik-Fields Reaction

Salicylaldehyde, unlike benzaldehyde, sets the Kabachnik-Fields reaction on the way of initial imine formation. This is explained by the thermodynamic instability of hydroxyphosphonates derived from salicyalaldehyde, which blocks the second possible Kabachnik-Fields reaction route involving intermediate hydroxyphosphonate formation. The kinetics and mechanism of addition of dialkyl hydrogen phosphites at the C=N bond of the intermediate N-substituted imines (the final stage of the "imine" Kabachnik-Fields reaction) are well consistent with the earlier proposed unified reaction mechanism

Thermochemistry of heteroatomic compounds. Part 6. Enthalpy of solvation and complex formation of some halides of three-coordinated phosphorus compounds in pyridine

Using previously published values of the enthalpies of solvation of some derivatives of three-coordinated phosphorus compounds, the contributions of the non-specific solvation enthalpies in the general solvation effect in benzene, p-xylene, methanol and pyridine have been calculated. Taking into account the known possibility of intramolecular complex formation between halogenated derivatives of PIII and pyridine, the magnitudes of specific interaction enthalpies for PCl3, PBr3, (EtO)2PCl, {A figure is presented} PCl and {A figure is presented} PBr were determinated. Thermodynamic parameters of complex formation between cyclic chlorophosphites and 1-dimethylamino-3,3-dimethyl-propan-2-one have been obtained and are discussed. © 1995

Kinetic study of the reaction of triphenylphosphine with acrylic acid in alcohol media

Kinetic study of the reaction of triphenylphosphine with acrylic acid in alcohol media was carried out by spectrophotometric method. Use of alcohols as solvents is shown to introduce a specific feature in the kinetic picture of the reaction due to the appearance of parallel channels of proton transfer: from alcohol and from another molecule of acrylic acid in the solution. © 2010 Pleiades Publishing, Ltd

Kinetics and mechanism of the Pudovik reaction in the azomethine series: I. Addition of dimethyl hydrogen phosphite to N-isopropylbenzalimines

For a series of phenyl-substituted N-isopropylbenzalimines, the effect of substituent on their capability to add dimethyl hydrogen phosphite was studied qualitatively in the condensed phase (DTA) and quantitatively (with determination of the kinetic and activation parameters) in 2-propanol solutions with spectrophotometric monitoring of the reaction. A reaction mechanism was proposed, involving formation of a highly organized four-membered transition state

Catalytic Preparative Chlorination of Cyclohexane with Tetrachloromethane in the Presence of Palladium Compounds

The reaction of cyclohexane with tetrachloromethane to yield cyclohexyl chloride and chloroform (metathesis of the alkane C-H bonds and tetrachloromethane C-Cl bonds) is efficiently catalyzed by the PdX2L2 palladium compounds (X = Cl, Br, I; L = PPh3, P(p-Tol)3, MeCN) at 70-120°C. Several types of catalytic systems differing in activity by three orders of magnitude are suggested. The most efficient system is one that contains triphenylphosphine complexes of palladium(II) dihalide, acetonitrile, and potassium carbonate, which provides the preparative yields (up to 83% with respect to hydrocarbon) of the metathesis products

Kinetics and mechanism of quaternization of tertiary phosphines with unsaturated carboxylic acids. Kinetic studies of the reactions in aprotic solvents

Data obtained while studying the kinetics of quaternization of tertiary phosphines with the unsaturated carboxylic acids in the series of aprotic solvents indicate the participation of a second molecule of acid playing the part of the external proton donor in this process. Quantitative analysis of the effect of solvent within the frames of the Koppel-Palm equation showed that the main contribution in the reaction rate belongs to the nucleophilicity of medium while the effects of polarity and electrophilicity are smaller. The results obtained suggest the step-by-step mechanism of interaction including the formation of the zwitterionic intermediate on the reaction pathway common for the solvents with different proton activity. © Pleiades Publishing, Ltd., 2011

Kinetic study of the reaction of tertiary phosphines with acrylic acid in aprotic solvents

The kinetics of the reaction of tertiary phosphines with acrylic acid in a series of aprotic solvents was studied by spectrophotometry. The data obtained suggest a stepwise mechanism of interaction including initial formation of zwitterionic intermediate followed by intermolecular proton transfer to the generated carbanionic center from the second molecule of acrylic acid. Copyright © Taylor & Francis Group, LLC

Kinetics and mechanism of the pudovik reaction in the azomethine series: II.1 Hydrolysis and catalysis in the reaction of dialkyl phosphites with benzalaniline

A 31P NMR study show that diisopropyl phosphite and benzalaniline do not react with each other as individual components. Adduct formation is made possible by partial hydrolysis of the dialkyl phosphite