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

• Published in: Measurement science & technology Vol. 11; no. 10; pp. 1421 - 1425
• Main Authors: Dávalos, Juan Z, Roux, M Victoria
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.10.2000; Institute of Physics
• Subjects: Calorimetry; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; Thermal instruments, apparatus and techniques; Design; Formation free enthalpy; Microcalorimeter; Construction; Enthalpy; Combustion products; Experimental study; Combustion gas analysis; Organic compounds; Testing
• ISSN: 0957-0233; 1361-6501
• DOI: 10.1088/0957-0233/11/10/301

To obtain reliable standard energies of combustion with small amounts of C, H, O compounds, a new microcombustion colorimetry system has been set up. The design, construction, calibration and measurement experiments are described. The system includes a commercial combustion bomb with an internal volume of 22 cm exp 3 . Samples of around 80 mg are suitable if one wants to retain the same levels of accuracy and reproducibility as those in macrocombustion experiments. Calibration of the calorimeter was performed using benzoic acid. epsilon (calorimeter) = 2083.74 plus /minus 0.48 J K exp -1 was obtained. Combustion measurements using m-methoxybenzoic acid were made in order to verify the chemistry of the combustion process involved in the corresponding analysis of results and the accuracy of the measurement of combustion energy. The uncertainty of the results shows that the instrument described and the experimental procedure used for the determination of enthalpies of formation of compounds containing C, H and O provide a high reliability.