For fluorocarbons

In a search for fluorocarbons having anesthetic properties 1 2 dichloro 1 1 difluoropropane was subjected to photochemical chlorination Two isomeric products were obtained one of which was identified as 1 2 3 tnchloro 1 1 difluoropropane What is the structure of the second com pound" ... 

As an excellent barrier resin, PTEE is widely used in the chemical industry. However, it is a poor barrier for fluorocarbon oils because similarity in the chemical composition of a barrier and a permeant increases permeation. Most Hquids and gases (other than fluorocarbons) do not permeate highly crystalline PTFE. Permeabilities at 30deg C (in mol/(m-s-Pa) X 10 ) are as follows CO2, 0.93 N2, 0.18 He, 2.47 anhydrous HCl, <0.01 (89). 

Surface Protection. The surface properties of fluorosihcones have been studied over a number of years. The CF group has the lowest known intermolecular force of polymer substituents. A study (6) of liquid and solid forms of fluorosihcones has included a comparison to fluorocarbon polymers. The low surface tensions for poly(3,3,3-trifluoropropyl)methylsiloxane and poly(3,3,4,4,5,5,6,6,6-nonafluorohexyl)methylsiloxane both resemble some of the lowest tensions for fluorocarbon polymers, eg, polytetrafluoroethylene. 

Diamine curatives were the first cross-linking agents for fluorocarbon mbbers. They are corrosive to mild steel molds and have been replaced in many appHcations by the bisphenol or other more recent cure systems. Nevertheless, some diamines are stiU used for food-contact appHcations of fluorocarbon mbbers and in zinc-free cures of halobutyl mbbers for pharmaceutical stoppers. Methylene dianiline and triethylene tetramine are cross-linking agents for ethylene—acryflc elastomers. 

Fig. 2. Tensile strength retention, continuous service, for fluorocarbon elastomers. Compound I (see Table 4).

Teflon is a registered trademark of E.I. DuPont de Nemours and Company for fluorocarbon resin. 

Szentirmay et al. studied the microchemical environments of Nafion 117 in the acid and Na+ forms using Py and Ru(bpy)32+ probes in fully hydrated ( 40%) samples in various cation forms.Ru(bpy)32+ emission spectra cannot be interpreted in terms of environmental polarity in as straightforward a fashion as in the case of Py, but blue shifts can reflect this aspect. One of the results of this study was that the microenvironment polarities were such that Lj//i values for Py are between those for fluorocarbon and aqueous environments, and this conclusion was strengthened by the results of Ru(bpy)3 + probe studies, as well as the similar conclusion of Lee and Meisel. Another conclusion that was reached was that the SOa" clusters are chemically heterogeneous, an idea that was in line with the view of Yeager and Steck, who spoke of mixed interfacial regions. ... 

Uses. Fluorinating agent incendiary igniter and propellant for rockets in nuclear reactor fuel processing pyrolysis inhibitor for fluorocarbon polymers... 

Uses are for fluorocarbons (66%), alumina (14%), petroleum alkylation catalysis (4%), stainless steel pickling (4%), and uranium chemical production (2%). 

It is also important to recognize that unique differences should be anticipated in the plasma chemistry of fluorocarbons from that of hydrocarbons. This can be attributed in part to the strong C—F bond and relatively weak F—F bond. Thus, while elimination of and HF is a favorable process in the case of hydrocarbons and fluorohydrocarbons, for fluorocarbons C—C bond cleavage is mere likely. For example ... 

Kelly, N. A K. L. Olson, and C. A. Wong, Tests for Fluorocarbon and Other Organic Vapor Release by Fluorocarbon Film Bags, Environ. Sci. Technol., 19, 361-364 (1985). 

Kay and Fust postulated the use of epoxy resin for inhibition of composite propellants [335] and as a consequence, epoxy resins were tried for the first time for the inhibition of HTPB-based composite propellants at Thiokol Corporation, USA. Subsequently, use of the amido-amine hardened modified bisphenol-A-based epoxy resin was reported as inhibitor for fluorocarbon-based composite propellants [336]. Epoxy resins are the most versatile resins for bonding applications for a variety of substrates. This is because of the following characteristics. 

Fig. 19. Correlation between DFs for fluorocarbonate polymers determined by ESCA, NMR and VPO...

Continuing dissatisfaction amongst fluorine chemists with the cumbersome alphanumeric ASHRAE ( Freon ) codes for fluorocarbons (which contain no provision for branched-chain compounds) has led to interesting proposals recently concerning alternative codes for HFCs and HFEs.10 To be fair to ASHRAE. when its predecessor, ASRE, standardized the so-called Du Pont code in the late 1950s, no one could have foreseen the proliferation of lists of volatile fluorocarbons (and hence coded designations) arising from the impressive commercial drive to locate environmentally acceptable in-kind replacements for C.FCs and Halons.8... 

Chain-transfer agents -m emulsion polymerization [LATEX TECITNOLOGY] (Vol 15) -for fluorocarbon elastomers [ELASTOMERS, SYNTHETIC - FLUOROCARBONELASTOMERS] (Vol 8)... 

Initiators -for acrylamide [ACRYLAMIDE POLYMERS] (Vol 1) -anionic initiators [INITIATORS - ANIONIC INITIATORS] (Voll4) -cationic initiators [INITIATORS - CATIONIC INITIATORS] (Vol 14) -in emulsion polymerization [LATEX TECHNOLOGY] (Vol 15) -for fluorocarbon elastomers [ELASTOMERS, SYNTHETIC - FLUOROCARBON ELASTOMERS] (Vol 8) -Free-radical initiators [INITIATORS - FREE-RADICAL INITIATORS] (Voll4) -organohthium compounds as [LITHIUM AND LITHIUM COMPOUNDS] (Vol 15) -peroxides as [PEROXIDES AND PEROXIDE COMPOUNDS - INORGANIC PEROXIDES] (Vol 18) -for propylene oxide [PROPYLENE OXIDE] (Vol 20) -for PUR polyols [POLYETHERS - PROPYLENE OXIDE POLYMERS] (Vol 19) -of suspension polymerization [ACRYLIC ESTER POLYMERS - SURVEY] (Vol 1)... 

Among esters of sucrose, some derivatives of fluorinated fatty acids have been prepared for evaluation as surfactants specifically designed for fluorocarbons containing emulsions used for biomedical applications, notably as blood substitutes.98,402 Some sucrose aspartate surfactants have been described.403... 

Some of the inherent limitations in this method of forming trifluoromethyl compounds can presumably be overcome. One approach would be to examine catalytic decarbonylations, a type of reaction that has been observed for hydrocarbon acyl derivatives but not, as yet, for fluorocarbon acyl compounds (39). In one reaction that is at least formally related, the preparation of (CF3)2Hg by the decarboxylation of (CF3C02)2Hg, the loss of C02 occurs readily only in the presence of added K2C03 (40). 

The hot, gaseous hydrogen fluoride is either absorbed in water or liquefied refrigeration is employed to obtain the anhydrous product needed for fluorocarbon manufacture and other uses. Although hydrofluoric acid is corrosive, concentrations of 60% and above can be handled in steel at lower temperatures lead, carbon, and special alloys are also used in the process equipment. 

The terminal -CF3 group 20% larger than the -CH3 group and the same rationale applies for the -CF2- group versus the -CH2- group. This means that intermolecular forces/unit volume for fluorocarbons are less than that for hydrocarbons of similar structure. 

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