ABSTRACT

The vapor pressures of imidazole, N-methylimidazole and of their dichloro and dicyano substituted compounds were measured at different temperatures, in the crystalline phase for two of them, and in crystalline and liquid phases for the other four. From these measurements, enthalpies and standard entropies of sublimation and vaporization were derived. The results allowed the determination of the triple points (p, T) coordinates of the four compounds studied in both condensed phases as well as the calculation of their enthalpy of fusion. Enthalpies and temperatures of fusion were also determined using d.s.c. The experimental results enabled the estimation of the enthalpy of the intermolecular N-H...N bonds in the imidazoles studied.

Compounds

#	Formula	Name
1	C3H4N2	1H-imidazole
2	C4H6N2	1-methylimidazole
3	C4H4Cl2N2	4,5-dichloro-1-methyl-1H-imidazole
4	C6H4N4	1-methyl-1H-imidazole-4,5-dicarbonitrile
5	C3H2Cl2N2	4,5-dichloroimidazole
6	C5H2N4	4,5-dicyanoimidazole

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	1	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	1	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	1	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Closed cell (Static) method	19
POMD	1	Vapor or sublimation pressure, kPa ; Metastable liquid	Temperature, K; Metastable liquid	Metastable liquid Gas	Closed cell (Static) method	18
POMD	2	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	2	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	2	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Closed cell (Static) method	11
POMD	2	Vapor or sublimation pressure, kPa ; Metastable liquid	Temperature, K; Metastable liquid	Metastable liquid Gas	Closed cell (Static) method	27
POMD	3	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	3	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	3	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Closed cell (Static) method	20
POMD	3	Vapor or sublimation pressure, kPa ; Metastable liquid	Temperature, K; Metastable liquid	Metastable liquid Gas	Closed cell (Static) method	11
POMD	4	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	4	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	4	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Closed cell (Static) method	15
POMD	4	Vapor or sublimation pressure, kPa ; Metastable liquid	Temperature, K; Metastable liquid	Metastable liquid Gas	Closed cell (Static) method	27
POMD	5	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	5	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	5	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Closed cell (Static) method	32
POMD	6	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	6	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	6	Vapor or sublimation pressure, kPa ; Crystal	Temperature, K; Crystal	Crystal Gas	Calculated from knudsen effusion weight loss	28

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

Thermodynamic study of phase transitions of imidazoles and 1-methylimidazoles

Almeida, A. R. R. P.[Ana R.R.P.], Monte, M. J. S.[Manuel J. S.]

ABSTRACT