Calibration and testing of an isoperibolic micro-combustion calorimeter developed to measure the enthalpy of combustion of organic compounds containing C, H, O and N

Abstract

In order to obtain reliable data of the standard enthalpy of combustion of compounds containing carbon, hydrogen, oxygen, and nitrogen atoms, an isoperibolic micro-combustion calorimeter has been developed from a 22cm3 1109A Parr semi-micro oxygen bomb. The calorimeter was calibrated with standard benzoic acid and the resulting energy equivalent was ε(calor)=(1497.39±0.37)J·K−1, which means an uncertainty of 0.027%. Combustion measurements using salicylic acid and 1,2,4-triazole were made in order to verify the accuracy of the device. The values of −Δcu° at T=298.15K for the compounds were (21877.2±4.6)J·g−1, and (19217.7±1.9)J·g−1, respectively, in agreement with the literature values.