Fluoroethers synthesis

Examples of successful fluorination syntheses accomplished in the solid state include the fluorination of polymers7 9, see Table 2 and formation of 2, 4 and 6, and the synthesis of per-fluoroethers and many other oxygen containing fluorocarbon compounds10-12 e.g. 7, 8, and 9 see also Figure 2. 

During the year 1970, several articles were published by Kim et al. [41-46] about the synthesis and the properties of fluorinated hybrid silicone homopolymers and copolymers. These polymers were obtained by hydrosilylation of a, (D-dienes with chlorohydrogenosilanes, and the obtained bis-chlorosilanes were then hydrolysed into bis-silanols and polymerized or copolycondensed (R = R or R or R or R, Z = alkyl, aUcyl ether, fluoroalkyl, fluoroether, etc.) (cf. Scheme 19). 

Although exactly what governs solubility in CO2 is not entirely clear, several classes of compounds have been identified as having high solubility in CO2, such as fluoroethers, fluoroacrylates, and silicones. These molecules have been used in the design and synthesis of surfactants for applications in CO2. 

Figure 6 Indicates attempts to build elastomeric properties Into a polymer by Incorporating a fluoroether chain Into a polylmlde system (. Line 1 shows an aryl diamine polymer Intermediate prepared In a lengthy series of synthesis steps from a perfluoroalkylene ether dlcarboxyllc acid. The polymer Is prepared from the reaction of the diamine with perfluoro-hexamethylene-bis(phthalic anhydride). As expected, the polymer had excellent thermal stability, but, again. Its low-temperature properties were deficient. For example, en X + y = 0, the Tg was 130 C when x + y = 1, the Tg was 110 C and when x + y = 3, the Tg was 80 C. With this system, we are unable to achieve requisite (lialn flexibility because of a preponderance of rigid aromatic groups that Inhibit elasticity and cause a raising of the T beyond practical limits for our Intended purpose as a sealant material. The fluoroether segment Is simply too short to yield a useful low-temperature elastomer.

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