Construction, calibration and testing of a micro-combustion calorimeter

An isoperibolic micro-combustion calorimeter was designed, built and set up in our laboratory, taking as base a 1107 Parr combustion bomb of 22 cm3 of volume. Taken into account the geometrical form of the bomb, it was designed and constructed a vessel and a submarine chamber in brass. All of the pieces of the calorimeter were chromium-plated to reduce heat loss by radiation. The calorimeter was calibrated by using pellets of standard benzoic acid (mass approximate of 40 mg) leading to the energy equivalent of ε(calor) = (1283.8 ± 0.6) J · K−1. In order to test the calorimeter, combustion experiments of salicylic acid were performed leading to a value of combustion energy of Δcu∘ = −(21,888.8 ± 10.9) J · g−1, which agrees with the reported literature values. The combustion of piperonylic acid was carried out as a further test leading to a value of combustion energy of Δcu∘ = −(20,215.9 ± 10.4) J · g−1 in accordance with the reported literature value. The uncertainty of the calibration and the combustion of salicylic acid and piperonylic acid was 0.05%.