ABSTRACT

The Knudsen mass-loss effusion technique was used to measure the vapor pressures, between 0.1 Pa and 1 Pa, of the three monomethyl benzenedicarboxylates over the following temperature intervals: monomethyl phthalate, between 335.28 K and 355.28 K; monomethyl isophthalate, between 359.26 K and 379.12 K; monomethyl terephthalate, between 363.16 K and 381.51 K. From the variation of the vapor pressures with temperature, the standard molar enthalpies, entropies, and Gibbs energies of sublimation at T ) 298.15 K were calculated. The volatility of the studied compounds is compared with the volatilities of the benzene dicarboxylic acids and of the dimethyl benzenedicarboxylates.

Compounds

#	Formula	Name
1	C9H8O4	phthalic acid, monomethyl ester
2	C9H8O4	1,3-benzenedicarboxylic acid, monomethyl ester
3	C9H8O4	1,4-benzenedicarboxylic acid, monomethyl ester

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	Calculated from knudsen effusion weight loss	33
POMD	2	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC:FP	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	Calculated from knudsen effusion weight loss	31
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	Calculated from knudsen effusion weight loss	26

Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

Vapor Pressures and Phase Changes Enthalpy and Gibbs Energy of Three Crystalline Monomethyl Benzenedicarboxylates

Monte, M. J. S.[Manuel J. S.], Sousa, C. A. D.[Carlos A. D.]

ABSTRACT