Mass spectrometric study of C60 and C60-NiF2 fluorination with molecular fluorine

Fluorination of [60]fullerene and [60]fullerene-NiF2(s) has been studied in situ by Knudsen cell mass spectrometry with admission of molecular fluorine. The fluorination processes were controlled in the temperature range 500 - 800 K at molecular fluorine pressure 10(-4) - 10(-5) atm. Temperature, time of fluorination and fluorine pressure were varied during the investigation. It was found that variation of these parameters did not lead to the selective fluorination. It was shown that NiF2(s) significantly influences the composition of the product mixture: a large amount of nickel difluoride in the system suppresses the fluorination reaction while the presence of a small amount promotes the selective fluorination. C60F18 (50% in the gas phase) was produced in our experiments under the following conditions: 20 h, 720 K, P(F-2) = 2 . 10(-4) atm in the prefluorinated (inner surface covered with NiF2(s) layer) Ni-reactor. An important point of the study was verification of the thermodynamic equilibrium in the system. It was concluded that the equilibrium is not established in the system under study, and the fluorination is governed by kinetic factors.