The design, construction and testing of a microcombustion calorimeter suitable for organic compounds containing C, H and O

To obtain reliable standard energies of combustion with small amounts of C, H, O compounds, a new microcombustion calorimetry system has been set up. The design, construction, calibration and measurement experiments are descr ibed. The system includes a commercial combustion bomb with an internal vol ume of 22 cm(3). Samples of around 80 mg are suitable if one wants to retai n the same levels of accuracy and reproducibility as those in macrocombusti on experiments. Calibration of the calorimeter was performed using benzoic acid. epsilon>(*) over bar * (calorimeter) = 2083.74 +/- 0.48 J K-1 was obt ained. Combustion measurements using m-methoxybenzoic acid were made in ord er to verify the chemistry of the combustion process involved in the corres ponding analysis of results and the accuracy of the measurement of combusti on energy. The uncertainty of the results shows that the instrument describ ed and the experimental procedure used for the determination of enthalpies of formation of compounds containing C, H and O provide a high reliability.