ABSTRACT

The gas-phase enthalpies of formation of 2-, 3-, and 4-methylbenzonitrile at T = 298.15 K were studied by combustion calorimetry, and their vaporization enthalpies were determined using the transpiration method. The composite ab initio methods W1-F12 and G4 were used to calculate the gas-phase enthalpies of formation for these three methylbenzonitriles. These theoretical values were found to be in excellent agreement with the corresponding experimental data. The analysis of these data revealed that the interaction between cyano and methyl groups is slightly stabilizing. Using the experimental data a set of group-additivity terms, which allows to estimate thermochemical properties for methyl and cyano substituted benzenes, was proposed. These terms, together with theoretical data, were subsequently used to reassess the thermochemical properties of 2,6-dimethylbenzonitrile and 2,4,6-trimethylbenzonitrile.

Compounds

#	Formula	Name
1	CO2	carbon dioxide
2	N2	nitrogen
3	H2O	water
4	O2	oxygen
5	C8H7N	2-methylbenzonitrile
6	C8H7N	3-cyanotoluene
7	C8H7N	4-cyanotoluene
8	C10H11N	2,4,6-trimethylbenzonitrile

Datasets

The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type	Compound-#	Property	Variable	Phase	Method	#Points
POMD	5	Vapor or sublimation pressure, kPa ; Liquid	Temperature, K; Liquid	Liquid Gas	Transpiration method	18
POMD	6	Vapor or sublimation pressure, kPa ; Liquid	Temperature, K; Liquid	Liquid Gas	Transpiration method	17
POMD	7	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	7	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	7	Vapor or sublimation pressure, kPa ; Liquid	Temperature, K; Liquid	Liquid Gas	Transpiration method	16
POMD	8	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	8	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
RXND	5 1 2 3 4	Specific internal energy of reaction at constant volume, J/g			Static bomb calorimetry	1
RXND	6 1 2 3 4	Specific internal energy of reaction at constant volume, J/g			Static bomb calorimetry	1
RXND	7 1 2 3 4	Specific internal energy of reaction at constant volume, J/g			Static bomb calorimetry	1

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Benchmark thermochemistry of methylbenzonitriles: Experimental and theoretical study

Zaitseva, K. V.[Ksenia V.], Emel'yanenko, V. N.[Vladimir N.], Agapito, F.[Filipe], Pimerzin, A. A.[Andrey A.], Varfolomeev, M. A.[Mikhail A.], Verevkin, S. P.[Sergey P.]

ABSTRACT