Activation and reaction volumes of the reactions of o-and p-nitrophenylsulfenyl chlorides with styrene and cyclohexene in some solvents

The effect of hydrostatic pressure below 1000 kg cm-2 on the rate of reactions of o-and p-nitrophenylsulfenyl chlorides with styrene and cyclohexene was studied. The activation and reaction volumes (cm3 mol-1) for the reactions of o-nitrophenylsulfenyl chloride with styrene in acetonitrile (-23.1 and -23.6), 1,2-dichloroethane (-29.2 and -24.7), chlorobenzene (no, -20.2), and anisole (-25.1 and -21.2) and for the reaction of p-nitrophenylsulfenyl chloride with styrene in carbon tetrachloride (-39.5±1.5 and -22.0) were determined. In carbon tetrachloride the activation volumes for the reactions of cyclohexene with o-and p-nitrophenylsulfenyl chlorides (-37.7±2.0 and -40.9±1.2 cm 3 mol-1, respectively) are almost the same and coincide with the data for the reactions with styrene. The considerable decrease in the volume of the transition state in the nonpolar solvent is considered as a consequence of the enhanced electrostriction of carbon tetrachloride in the solvate sphere of the transition state of the reaction, which excludes the nonpolar transition state of the sulfuran type. © 2007 Springer Science+Business Media, Inc

Solvent effect on the partial molar volume and solution enthalpy of ferrocene

A small distinction of solution enthalpy and partial molar volume in eighteen solvents of different polarity corresponds to the inaccessibility of capsulated charges inside of ferrocene for the interaction with surrounding molecules. © 2012 Mendeleev Communications. All rights reserved

Multimedia Partition for the Students’ Independent Work Organization

A new type of multimedia visualization in music education – multimedia score is considered. A multimedia partition possibilities are named, the content of organization of extracurricular independent work of students in familiarization musical-theoretical disciplines with the multimedia partition is revealed.Рассматривается новый вид мультимедийной наглядности, применяемый в музыкальном образовании — мультимедийная партитура. Названы возможности мультимедийной партитуры, раскрыто содержание организации внеаудиторной самостоятельной работы студентов при освоении музыкально-теоретических дисциплин с применением мультимедийной партитуры

Enthalpy and entropy of activation and the heat effect of the ene reaction between 4-phenyl-1,2,4-triazoline-3,5-dione and 2,3-dimethyl-2-butene in solution

The rate of the fastest ene reaction between 4-phenyl-1,2,4-triazoline-3,5- dione (1) and 2,3-dimethyl-2-butene (2) is studied by means of stopped flow in solutions of benzene (k 2 = 55.6 ± 0.5 and 90.5 ± 1.3 L mol-1 s-1 at 23.3 and 40°C) and 1,2-dichloroethane (335 ± 9 L mol-1 s-1 at 23.5°C). The enthalpy of reaction (-139.2 ± 0.6 kJ/mol in toluene and -150.2 ± 1.4 kJ/mol in 1,2-dichloroethane) and the enthalpy (20.0 ± 0.5 kJ/mol) and entropy (144 ± 2 J mol-1 K-1) of activation are determined. A clear correlation is observed between the reaction rate and ionization potential in a series of ene reactions of 4-phenyl-1,2,4-tri-azoline- 3,5-dione with acyclic alkenes. © 2014 Pleiades Publishing, Ltd

Influence of packing of the reactants and products in solution on the volume parameters of the diels-alder reaction

The possible causes of a dramatic difference in the volume parameters (by up to 15-20 cm3 mol-1) of the Diels-Alder reactions involving bulky and small reactants are discussed. The partial molar volumes of anthracene and 9,10-dihydroanthracene and the heats of their solution in six solvents were determined. ©2004 MAIK "Nauka/Interperiodica"

Solvent effect on the heat of solution and partial molar volume of some non-electrolytes and lithium perchlorate

For several non-electrolytes and for lithium perchlorate the solvent effect on the heat of solution and partial molar volumes was studied. In the absence of the donor-acceptor and electrostatic interactions, clear proportionality can be seen only in the alkane solutions and these changes are defined by the non-alkane component. For solutions of π-acceptor (tetracyanoethylene) and v-acceptor (gallium chloride) in the presence of π,π-, π,V- and n,v-complexes, the relation between the changes of interaction energy and the values of the partial molar volumes can be seen. The maximum change in the value of partial molar volumes (up to 50cm mo1-1) was noted for lithium perchlorate in ten solvents. The volume change is proportional to the compressibility coefficients of the solvents and correlates less with the values of heat of solution and solvent permittivity. Copyright © 2006 John Wiley & Sons, Ltd

Effect of pressure on the rate of the Diels-Alder reaction of diethyl azodicarboxylate with 9,10-dimethylanthracene

The enthalpy, entropy, and volume of activation and volume of the Diels-Alder reaction of diethyl azodicarboxylate with 9,10-dimethylanthracene in 1,2-dichloroethane have been determined. Possible factors responsible for the sharp difference between the volumes of activation and reaction are considered. © 2014 Pleiades Publishing, Ltd

Enthalpies of solution and partial molar volumes of magnesium perchlorate in alcohols and salt effect of acceleration of the Diels-Alder reaction

Densities and enthalpies of solution at 25°C were measured for dilute solutions of magnesium perchlorate (MP) in some alcohols using the Anton Paar DSA 5000M vibrating tube densimeter and differential calorimetric measurements. In all studied solvents the solution of MP was highly exothermic and large solvent volume contraction was observed. Maximum effect was obtained in methanol and ethanol solutions. Acceleration effect of the Diels-Alder reaction of 9,10-dimethylanthracene with acrylonitrile (in medium of acrylonitrile) in the presence of salts LiClO4, Mg(ClO4)2 and GaCl3 was as 18:160:59,000. © 2011 Elsevier B.V