Graphite fluoride

N. Watanabe, T. Nakajima, and H. Touhara, Studies in Inorganic Chemistry 8, Graphite Fluorides, Elsevier Science PubHshers, New York, 1988. 

Various other soft materials without the layer—lattice stmcture are used as soHd lubricants (58), eg, basic white lead or lead carbonate [598-63-0] used in thread compounds, lime [1305-78-8] as a carrier in wire drawing, talc [14807-96-6] and bentonite [1302-78-9] as fillers for grease for cable pulling, and zinc oxide [1314-13-2] in high load capacity greases. Graphite fluoride is effective as a thin-film lubricant up to 400°C and is especially useful with a suitable binder such as polyimide varnish (59). Boric acid has been shown to have promise as a self-replenishing soHd composite (60). 

Graphite fluoride continues to be of interest as a high temperature lubricant (6). Careful temperature control at 627 3° C results in the synthesis of poly(carbon monofluoride) [25136-85-0] (6). The compound remains stable in air to ca 600°C and is a superior lubricant under extreme conditions of high temperatures, heavy loads, and oxidising conditions (see Lubrication and lubricants). It can be used as an anode for high energy batteries (qv). 

Waranabe N Nakajima T Touhara, H Graphite Fluorides (Studies in Inorganic Chemistry, Vol 8) Elsevier Amsterdam New York ... 

Fluorinatton of graphite with fluorine gives graphite fluorides that have interesting properties, as recently reviewed [63]. Pyridine and its derivatives add elemental fluorine to form unstable N-fluoro adducts [14, 26, 64, 65]. These may decompose to 2-fluoropyndines [65] or be stabilized by treatment with inflate salts to form useful electrophilic fluonnating agents [64]... 

Watanabe, N, Nakajima, T, Touhaia, H Graphite Fluorides, Elsevier Amsterdam, Netherlands, 1988... 

Although the covalent compounds of graphite are thus important in their own right, they represent the extreme form of oxidative intercalation. The use of fluoride compounds to achieve highly conductive materials may ultimately lead to new forms of graphite fluoride SI). 

Infrared spectra and F-NMR spectroscopy showed the presence of IF5 and covalently bonded fluorine. Grafoil turns white upon intercalation with IF, this is reminiscent of graphite fluoride, CFi.ij (1,6). The IF, intercalate also evolves IF5 upon heating, but at much higher temperatures than C/IF5 this has been attributed to the lowered mobility of IF5 in the fluorinated matrix, which may no longer be planar. At 450°C, considerable amounts of fluorocarbons are evolved. 

Removal of higher fluorocarbons (above C4) from the circulating gas stream prevents explosive decomposition of the graphite fluoride [5],... 

Antimony dichloride trifluoride, 3 62t Antimony dioxide, 3 59 Antimony graphite fluoride, 3 63-64 Antimony halides, physical properties of, 3 61t... 

Mesophase pitch, consisting of a mixture of various aromatic hydrocarbons, reacts with fluorine between 50-130°C to give pitch fluorides [56] with the composition CFj 3 to CF159. These materials have a higher fluorine content than graphite fluoride (see Section 2.7), have very low surface energy and are soluble in some fluorinated solvents. 

Watanabe N, Nakajima T, Touhara H (1988) Graphite Fluorides. Elsevier, New York... 

In equation 5, C is amorphous carbon and CF2 changes to many perfluorocarbons, such as CF4, C2F6, etc., by secondary reactions. The surface coverage of graphite fluoride on the anode depends on the relative reaction rates of equations 4 and 5. Equation 6 has been introduced to analyze the wettability of the carbon surface with graphite fluoride formed on it.2 It shows the relationship between the fraction of effective surface for equation 3 per unit surface area of carbon (a) and the contact angle (0) of a fluorine gas bubble on the surface of the carbon electrode.2... 

The addition of lithium fluoride, due to its solubility in a fluorine bath, can suppress the occurrence of the anode effect.2 Nakajima and co-workers reported that the carbon/hydrogen fluoride/fluorine system formed the graphite fluoride intercalation compound C4F as a solid... 

Carbon fluoride [also known as carbon monofluoride, polycarbon monofluoride, graphite fluoride, or (CFx)n] is a solid, layered, non-stoichiometric fluorocarbon of empirical formula CFX, where 0 < x < 1.25, obtained by the action of elemental fluorine on carbon. Fluorine combines with carbon and yields three solid compounds CFX, C2FX, and C4FX as well as varying amounts of volatile fluorocarbons as byproducts. With appropriate selection of fluorination conditions nearly 100% conversion of carbon to carbon tetrafluoride can occur. 

Natural graphite is the most representative carbon with a high crystallinity. Upon fluorination, the graphite fluoride obtained also has a relatively high crystallinity. The reaction temperature range is from 350 to 600 °C. Figure 36 illustrates the reaction at various temperatures. 

Table 1. Synthesis of Graphite Fluorides and Carbon Fluorides...

An ideal kinetic study would be made under conditions where the product is only graphite fluoride or polycarbon monofluoride with no byproducts formed. In terms of reaction kinetics, one method to follow the reaction is to measure the weight change as a function of the reaction time. Using this method the reaction rate of fluorine with carbon can be evaluated. Various carbon structures have been employed with sufficient fluorination contact time provided at a particular temperature for the carbon to reach fluorine saturation. The weight increase vs the temperature can be monitored at atmospheric pressure. Figure 515 shows the carbon structure and the temperature dependency of the fluorination reaction of various graphites. 

Table 2. X-ray Diffraction Data of Graphite, Graphite Fluoride, and Carbon Fluoride...

Graphite Fluorides and Carbon Fluorine Compounds CRC Press Boca Raton, FL, 1991. 

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