Reaction with tetrafluoromethane and other fluoromethanes

The reversibility of the dismutation equilibrium. Equation (13.3) cf. Section 8.2, has been proven at high temperatures over a platinum catalyst (see Section 13.13) [1755]. However, when mixtures of COj and CF were heated to 1036 K or 1173 K, no reaction was apparent, even after 3 weeks. The formation of COF j from CO j and CF is thermodynamically favoured at low temperatures, although the time taken to reach equilibrium may be excessively long. 

At temperatures around 900 C, CCljFj reacts with carbon dioxide according to 

The reaction proceeds in the reverse direction at lower temperatures (see Section 13.13). 

Mixing of COj and NFj, at equal flow rates through a nickel tube at 825 C, gave a reaction consistent with the equation  

The COFj is produced with a yield of 80 %, but the contact times required for the reaction are excessively long ( 2000 min). Further reaction of the NOF with the CO, starting material gives rise to the reaction by-products CF, NO, and NO [770a]. 

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