Benzoic acid and concentrated ammonia were chosen as reactants and a compound ammonium benzoate was synthesized using the method of liquid phase reaction. FTIR, elemental analysis and X-ray powder diffraction technique were applied to characterize the structure and composition of the compound. Low temperature heat capacities of the solid compound were measured by a precision automated adiabatic calorimeter over the * Manuscript Click here to view linked References 2 temperature range from 80 to 399 K. A polynomial equation of the heat capacities was fitted by the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the interval of 5 K. In accordance with Hess' law, a thermochemical cycle was designed, the enthalpy change of the reaction of benzoic acid with ammonium acetate was determined as (15.585 +- 0.504) kJ amol-1, and the standard molar enthalpy of formation of the compound was calculated as -(501.835 +- 0.621) kJ amol-1 by an isoperibol solution-reaction calorimeter.
Compounds
#
Formula
Name
1
C2H4O2
acetic acid
2
C7H6O2
benzoic acid
3
C2H7NO2
ammonium acetate
4
C7H9NO2
ammonium benzoate
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
Constraint
Phase
Method
#Points
POMD
4
Molar heat capacity at constant pressure, J/K/mol ; Crystal