Perfluorocarbons also

For pure nonhydrocarbon organics, the most accurate method for predic tion of critical temperature for all compound groups is also the Ambrose" method. Equation (2-1) applies to all nonhydrocarbon compounds except perfluorocarbons, where the constant 1.242 is replaced by 1.570. For compounds containing any of C, H, O, N, S, or halogens up to C13 and ranging in critical temperature from 228-790 K, the average error is about 6 K. 

Attention should also be directed to the growing number of perfluorocarbon-sulfur species which feature single, double or even triple C-S bonds, e.g. ... 

A set of aryl halides was reacted with carbonyl hydrazides and molybdenum hexacar-bonyl [Mo(CO)6] as a source of carbon monoxide, employing fluorous triphenylphos-phine (F-TPP) as ligand and the perfluorocarbon liquid FC-84 as a perfluorinated solvent (Scheme 7.87 see also Scheme 6.46c). 

A liquid perfluorocarbon was being used as solvent in an oxidation by oxygen under pressure more energy was released than expected [1], It is cautioned that fluorocarbons are not inert to oxidation, presumably to carbonyl fluoride. An explosion has been experienced with perfluorotoluene in like circumstances [2], A correspondent reports that perfluorotoluene is flammable in air, more saturated perfluorocarbons in pure oxygen [3], Another detailed the combustion performance of polytetrafluoroethylene 148 kcal/mole ignition temperature not below 465°C at 7000 psi of oxygen [4], the product is mostly carbonyl fluoride. Other oxidants may also present a risk in extreme circumstances. 

For the use of perfluorocarbon molecules for ophthalmologic applications, see also in this volume the chapter by D. Menz and J.H. Dresp. 

Replacing some of the fluorine atoms by hydrogen atoms increases the polarity. Hydrofluorocarbons are more polar than the corresponding perfluorocarbons. They can also be even more polar than their hydrocarbon analogues. ... 

The thermal decomposition of straight-chain perfluorocarbons and PTFE is also believed to take place via difluorocarbene. The pyrolysis of PTFE at about 500 C in vacuo gives exclusively the monomer. 

Electrochemical fluorination (ECF) is described in Section 6.4.7. for the manufacture of surface-active agents. Coproducts from the ECF of octylsulfonyl fluoride are linear perfluoro-carbons containing from three to eight carbon atoms, while octanoyl fluoride yields a mixture of perfluorocyclic ethers containing mainly perfluoro(2-butyltetrahydrofuran) and perfluoro(2-propylpyran). ECF is also used for the manufacture of specific perfluorocarbon fluids, notably perfluoro(tripropylamine) and perfluoro(tripentylamine), from the corresponding hydrocarbon analogs. 

Under appropriate conditions, the perfluorocarbon (CF3)3CCF2CF2-C(CF3)3is obtained in 89%yield (70b). As may be seen from the reaction scheme, a number of partially fluorinated products are also isolable and it is clear that the protons are readily accessible to fluorine. The physical properties of highly branched fluorocarbons (see Table IX) are most unusual. 

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