670-54-2Relevant articles and documents
Effect of external pressure and solvent on the equilibrium constant of the Diels-Alder reaction of 9-chloroanthracene with tetracyanoethylene
Kiselev,Iskhakova,Shikhab,Konovalov
, p. 1565 - 1569 (2001)
The effect of external pressure and solvent on the equilibrium constant of the Diels-Alder reaction of tetracyanoethylene with 9-chloroanthracene at 25°C was studied. The molar reaction volume is strongly solvent-dependent, cm3/mol: -11.3±1.0 in ?-xylene, -14.9±1.0 in toluene, -20.6±1.5 in 1,2-dichloroethane, -22.6±1.5 in ethyl acetate, and -24.2±1.5 in acetonitrile.
Haines et al.
, p. 820 (1970)
Structure of Spurs in γ-Irradiated Alcohol Matrices Determined by Electron Spin-Echo Method
Ichikawa, Tsuneki,Wakasugi, Shin-ichi,Yoshida, Hiroshi
, p. 3583 - 3586 (1985)
Paramagnetic relaxation rates of radiation-generated tetracyanoethylene anion radicals (TCNE(1-)) and chemically prepared TCNE(1-) in the glassy matrices of ethanol, 1-propanol and 1-butanol, and radiation-generated CH3CHOH radicals in neat ethanol matrices have been measured by an electron spin-echo method for elucidating the detailed structure of spurs generated in the alcohol matrices γ-irradiated at 77 K.The local concentrations of hydroxyalkyl radicals generated in pair with TCNE(1-) or CH3CHOH radicals in isolated spurs were determined by analyzing the rates of excitation transfer from the magnetically excited TCNE(1-) or CH3CHOH radicals to the hydroxylakyl radicals.Comparison of the local concentrations of CH3CHOH radicals in ethanol matrices with and without solute tetracyanoethylene reveaked that the average number of ion pairs in a spur is close to unity.The distribution function of the distance r between TCNE(1-) and the paired hydroxyalyl radical, φ(r), was derived from relaxation kinetics of TCNE(1-), and was found to be expressed by φ(r)=3 exp(-r6/r06)(2?3/2r03).The average distances between TCNE(1-) and the paired hydroxyalkyl radicals were determined from the local concentrations of the hydroxyalkyl radicals, and were about 5 nm for all the alcohol matrices.
Reactivity Variation of Tetracyanoethylene and 4-Phenyl-1,2,4-Triazoline-3,5-Dione in Cycloaddition Reactions in Solutions
Kiselev, Vladimir D.,Kornilov, Dmitry A.,Anikin, Oleg V.,Shulyatiev, Alexey A.,Konovalov, Alexander I.
, p. 31 - 44 (2019/01/29)
The reasons for the very high reactivity and variability of reactivity of two dienophiles, tetracyanoethylene (1) and 4-phenyl-1,2,4-triazoline-3,5-dione (2), in the Diels–Alder reactions were considered. The data on the rate of reactions with anthracene (3), benzanthracene (4) and dibenzanthracene (5) in 14 solvents over a range of temperatures and high pressures, data on the change in the enthalpy of solvation of reagents, transition state, and adducts in the forward and backward reactions, and the enthalpies of these reactions in solution were obtained. Strong π-acceptor dienophile 1 has sharply reduced reactivity in reactions in π-donor aromatic solvents. It was observed that the π-acceptor properties of dienophile 1 disappear upon passage to the transition state and adduct. Large solvent effects on the reaction rate can be predicted for all types of reactions involving tetracyanoethylene. Very high reactivity of dienophiles 1 and, especially, 2 can be useful to catch such carcinogenic impurities such as 3–5 and neutralize them by transformation into less dangerous adducts.
Why can the activation volume of the cycloadduct decomposition in isopolar retro-diels-alder reactions be negative?
Kiselev, Vladimir D.
experimental part, p. 117 - 125 (2011/05/19)
Rate constants of the Diels-Alder cycloaddition reaction of anthracene with tetracyanoethylene, enthalpy of solution of reactants and adduct, enthalpy of the reaction in solution, enthalpy and entropy of activation of the forward and retro-Diels-Alder reactions were determined in 14 solvents. Temperature and pressure effects on the rate of the decomposition of the adduct formed from 9-chloroanthracene and tetracyanoethylene were studied. Since the electrostriction effect can be excluded from the consideration of the isopolar Diels-Alder reaction, negative values of the activation volume in the retro-Diels-Alder reactions can be caused by the different possibilities of penetration of the solvent molecules to large steric branched structures of the transition states and adducts.