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Combustion calorimetry of organic fluorine compounds by a rotating-bomb method

Journal Article · · J. Phys. Chem.; (United States)
DOI:https://doi.org/10.1021/j150542a014· OSTI ID:7305384

A rotating-bomb method was developed for the combustion calorimetry of organic fluorine compounds. Conventional methods of handling volatile samples could not be used, and a special technique with sealed, fused-quartz ampoules was devised. Some auxiliary data necessary for reduction of the calorimetric results to standard states were lacking: this difficulty was circumvented by use of suitable comparison or ''blank'' experiments. The following values, in kcal. mole/sup -1/, are reported for the standard heats of formation, ..delta..Hf/sup 0//sub 298.16/, of some organic fluorine compounds from graphite and gaseous hydrogen, oxygen and fluorine: o-fluorobenzoic acid (c), -134.3/sub 8/; m-fluorobenzoic acid(c), -137.8/sub 4/; p-fluorobenzoic acid (e), -138.9/sub 5/; fluorobenzene (liq.), -34.7/sub 5/; benzotrifluoride (liq.), -147.8/sub 5/ and polytetrafluoroethylene (granular, no heat treatment), -193./sub 5/. The samples of fluorobenzoic acids were purified by zone melting. p-Fluorobenzoic acid is proposed as a reference substance for intercomparison of bomb-calorimetric data for fluorine compounds among different laboratories.

Research Organization:
Bureau of Mines, Bartlesville, OK
OSTI ID:
7305384
Journal Information:
J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 60:8; ISSN JPCHA
Country of Publication:
United States
Language:
English