Thermochemistry in fluoro-solvents.

Abstract

Liquid phase fluorination methods of reaction calorimetry have been established using (1) a bromine-bromine trifluoride mixture and (2) fluorosulphuric acid. The heat of formation of (1) was obtained by measuring the heats of reaction with molybdenum and potassium iodate, bromide, persulphate and sulphate. A consistent heat of formation of the mixture was obtained and this value used to determine unknown heats of formation, e.g. antimonic and stannic fluorides. The heat of formation of potassium fluorosulphate was required in the scheme to determine a value for the bromine-bromine trifluoride mixture. The value for potassium fluorosulphate was obtained by reaction calorimetry in fluorosulphuric acid. The work in this solvent was extended and the heats of formation of sodium, cupric, nitronium, nitrosonium fluorosulphates were obtained. The heats of formation of other fluorosulphates were predicted via heat cycles. The proximity of values for hydrogen and fluoro-sulphates was an important empirical observation. The heats of formation of fluoro and chloro-sulphuric acids were determined and the values obtained combined with free energy functions to calculate possible dissociations of the acids. The theoretical values were compared with experimental observations. The heats of formation of a series of acids and bases in bromine trifluoride were measured. From the heats of neutralisation of these acids and bases the heats of formation of several ternary complexes were obtained. In addition, values were obtained for heat of autoionisation of bromine trifluoride.

Date of Award	1968
Original language	English
Awarding Institution	University of Bath