The effect of solvent on the reactions of allyltin (IV) compounds with singlet oxygen, 4-phenyl-1,2,4-triazoline-3,5-dione and diethyl azodicarboxylate

The effect of the influence on the increase of polarity of the solvent on the selectivity and rate of metalloene reactions of different allyltin compounds with singlet oxygen, 4-phenyl-1,2,4-triazoline-3,5-dione (TD) and diethyl azodicarboxylate has been studied.     

Studies on the reaction of organotin phenoxides with ethyl propiolate catalysed by triethylamine and tin(IV) chloride

Different tributyltin phenoxides react at room temperature with ethyl propiolate in benzene, in the presence of tin(IV) chloride, triethylamine and their mixture to give the derivatives of 3‐phenoxyacrylic acid ethyl ester. Exceptionally, 3‐(2‐hydroxyphenyl)acrylic acid ethyl ester and 3‐(2‐hydroxy‐5‐methylphenyl)acrylic acid ethyl ester have been obtained from the reaction of tributylphenoxytin and tributyl(p‐tolyloxy)tin, respectively catalysed by SnCl₄, and they have been easily hydrolysed to coumarin and 6‐methylcoumarin. Copyright © 2007 John Wiley & Sons, Ltd.     

Catalysis of reactions of allyltin compounds and organotin phenoxides by lithium perchlorate

The effect of increase of polarity of the solvent binary mixture methanol-benzene and acetonitrile-chloroform on the selectivity and the rate of metalloene reaction of different allyltin compounds with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), diethyl azodicarboxylate (DEAD) and singlet oxygen was studied. The more polar solvent favored the production of the M-ene product. Analogous comparative studies were carried out in Et₂O and 4 mol dm⁻³ solutions of LiClO₄ in diethyl ether. All studied reactions were strongly catalysed by LiClO₄. Physicochemical studies were carried out in purpose to explain the catalytic effect of LiClO₄ on the aforementioned reactions. In case of singlet oxygen and diethyl azodicarboxylate it was presumably a result of facilitation of the formation of the polar intermediate by the ionic medium. Whereas, in case of PTAD the mentioned previously effect could be associated with lowering its LUMO by association with lithium. The analogous catalytic effect of LiClO₄ was also observed for reactions of organotin phenoxides with DEAD and bis(trichloroethyl) azodicarboxylate leading to corresponding ring-aminated phenols in excellent yield, and with diethyl acetylenedicarboxylate giving a mixture of corresponding vinyl ethers and ring ethenylated phenols. Organotin phenoxides were distinctly more active than the corresponding phenols.     

Volumetric Properties of Some Aliphatic Mono- and Dicarboxylic Acids in Water at 298.15 K

The apparent molar volumes, V _φ , of two series of homologous aliphatic carboxylic acids, H(CH₂) _n COOH [n=0–5] and (CH₂) _n (COOH)₂ [n=0–5], were determined in dilute aqueous solutions by density measurements at T=298.15 K. Densities were measured using a vibrating-tube densimeter (DMA 5000, Anton Paar, Austria) at T=298.15 K. These results were used to calculate the apparent molar volumes of each solute over the concentration range 0.0050≤m/(mol⋅kg⁻¹)≤0.3000. Values of the apparent molar volumes of undissociated acids V_f(u)⁰V_{\phi (u)}^{0} were also calculated. The variation of V_f(u)⁰V_{\phi (u)}^{0} was determined as a function of the aliphatic chain length of the studied carboxylic acids.     

Volumetric properties of binary mixtures of alcoxyethanols with tert-butyl ethyl ether at various temperatures

Densities at 293.15, 298.15, 303.15, 308.15 and 313.15 K of the binary liquid mixtures made of tert-butyl ethyl ether with either 2-ethoxyethanol, or 2-(2-ethoxy)ethoxyethanol, or 2-[2-(2-ethoxy)ethoxy]ethoxyethanol have been measured over the whole mixture compositions. These data have been used to compute the excess molar volumes (V^E). The excess molar volumes always are negative over the entire range of composition for all the binary mixtures investigated. The changes of V^E with variations of the composition and the chain-length of the alkyl groups in the alkoxyethanol molecules are discussed in terms of possible intermolecular interactions.     

Thermodynamic and physicochemical properties of binary mixtures of nitromethane with {2-methoxyethanol + 2-butoxyethanol} systems at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K

The density, relative permittivity, viscosity and speed of sound at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K in the binary mixtures of nitromethane with 2-methoxyethanol and 2-butoxyethanol have been measured as a function of composition. From the experimental results, the excess molar volumes V^E, excess Gibbs free energy of activation for viscous flow $(\mathrm{\Delta }{G}^{1E})$, excess isentropic compressibility $({\kappa }_s^E)$ and the deviations in the relative permittivity, viscosity, and speed of sound from a mole fraction average have been calculated. The viscosity data, at T = 298.15 K, were correlated with equations of Hind et al., Grunberg and Nissan, Frenkel, and McAllister. The results are discussed in terms of intermolecular interactions and structure of studied binary mixtures.     

2-Methoxyethanol–Tetrahydrofuran–Binary Liquid System. Viscosities,densities, excess molar volumes and excess Gibbs activation energies of viscous flow at various temperatures

Densities (d ₁₂) and viscosities (η₁₂) have been measured for 2-methoxyethanol (ME) with tetrahydrofuran (THF) binary liquid mixtures over the whole composition range at various temperatures ranging from 291.15 to 308.15 K. The experimental data were used to test some empirical equations of the type: y ₁₂=y ₁₂(t) and y ₁₂=y ₁₂(X ₁) [where: y ₁₂−d ₁₂ or η₁₂]. From all these data, the excess molar volumes (V ₁₂ ^E), the excess viscosities (η₁₂ ^E) and excess Gibbs activation energies (ΔG ^*) of viscous flow were calculated. These structural parameters as a function of concentration suggest the formation of 3ME⋅THF and 2ME⋅THF types of intermolecular complexes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Studies on the catalysis of the reaction of organotin phenoxides with diethyl acetylenedicarboxylate

Different organotin phenoxides react at room temperature with diethyl acetylenedicarboxylate in diethyl ether, in the presence of lithium perchlorate to give a mixture of corresponding phenyl vinyl ethers and ring ethenylated phenols. Copyright © 2005 John Wiley & Sons, Ltd.     

Conductance studies of NaCl,KCl, NaBr,KBr, NaI,Bu<Subscript>4</Subscript>NI,and NaBPh<Subscript>4</Subscript> in water + 2-propoxyethanol mixtures at 298.15 K

The molar conductances of sodium chloride (NaCl), potassium chloride (KCl), sodium bromide (NaBr), sodium iodide (NaI), tetrabutylammonium iodide (Bu₄NI), and sodium tetraphenylborate (NaBPh₄) in water?+?2-propoxyethanol binary mixtures at T?=?298.15 K were determined. Conductance values were analyzed using a low-concentration chemical model (lcCM). The ionic conductivities of Na⁺, K⁺, Bu₄N⁺, Cl^?, I^?, Br^?, and BPh₄ ^? ions were determined using Fuoss–Hirsch’s assumption. The dependencies of the values of limiting molar conductance (Λ _o), limiting ionic conductance of the individual anions (λ _o ^± ), and Walden products (Λ _o???η and λ _o ^± ???η) as a function of the composition of water?+?2-propoxyethanol binary mixtures were discussed.

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Graphical abstract Limiting molar conductances Λ _o [S·cm²·mol^?1] of NaCl, NaBr, NaI, KCl, NaBPh₄, and NBu₄I as a function of the mole fraction, x ₂, in water (1)?+?2-propoxyethanol (2) mixtures at 298.15 K: empty diamonds NaCl, empty squares NaBr, empty triangles NaI, filled triangles KCl, filled squares NaBPh₄, and filled diamonds NBu₄I