ABSTRACT

The Knudsen mass-loss effusion technique was used to measure the vapor pressures at different temperatures of the following aminomethoxybenzoic acids: 2-amino-3-methoxybenzoic acid, between (349.12 and 369.18) K; 2-amino-5-methoxybenzoic acid, between (353.13 and 375.17) K; 3-amino-4-methoxybenzoic acid, between (379.67 and 399.18) K; 3-amino-5-methoxybenzoic acid, between (380.16 and 400.18) K; and 4-amino-3-methoxybenzoic acid, between (373.14 and 395.17) K. From the temperature dependences of the vapor pressure of the crystalline compounds, the standard (po = 105 Pa) molar enthalpies and Gibbs energies of sublimation, at T = 298.15 K, were derived. The results allowed the estimation of these two thermodynamic properties for two isomers not studied in this work 2-amino-6-methoxybenzoic acid and 3-amino-2-methoxybenzoic acid. Differential scanning calorimetry was used to measure the temperature and molar enthalpy of fusion of the studied isomers.

Compounds

#	Formula	Name
1	C8H9NO3	2-amino-3-methoxybenzoic acid
2	C8H9NO3	2-amino-5-methoxybenzoic acid
3	C8H9NO3	3-amino-4-methoxybenzoic acid
4	C8H9NO3	3-amino-5-methoxybenzoic acid
5	C8H9NO3	4-amino-3-methoxybenzoic acid

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 1		Crystal 1 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 ; Liquid	Temperature, K; Liquid	Liquid Gas	Calculated from knudsen effusion weight loss	33
POMD	2	Molar enthalpy of transition or fusion, kJ/mol ; Crystal 1		Crystal 1 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 ; Liquid	Temperature, K; Liquid	Liquid Gas	Calculated from knudsen effusion weight loss	34
POMD	3	Molar enthalpy of transition or fusion, kJ/mol ; Crystal 1		Crystal 1 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 ; Liquid	Temperature, K; Liquid	Liquid Gas	Calculated from knudsen effusion weight loss	29
POMD	4	Molar enthalpy of transition or fusion, kJ/mol ; Crystal 1		Crystal 1 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 ; Liquid	Temperature, K; Liquid	Liquid Gas	Calculated from knudsen effusion weight loss	30
POMD	5	Molar enthalpy of transition or fusion, kJ/mol ; Crystal 1		Crystal 1 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 ; Liquid	Temperature, K; Liquid	Liquid Gas	Calculated from knudsen effusion weight loss	34

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

Thermodynamic Study on the Sublimation of Five Aminomethoxybenzoic Acids

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

ABSTRACT