Perfluoroalkylethyl iodides

One new method for converting 2-perfluoroalkylethyl iodides to the alcohols involves treatmentwith amides that nun irmzedehydroiodination. Wet dimethyltormamide with a water content of 1 2% favors formation of the alcohol [5(7] (equation 50)... 

Hydrolysis of 2-perfluoroalkylethyl iodides in the presence of nitrites also gives 2-perfluoroalkylethanols [5/] (equation 51). A variety of solvents can be used, but acetonitrile appears the most effective. Solvents can be avoided by using a betaine surfactant as a phase-transfer catalyst. 

Hydrogen iodide is easily eliminated by strong bases from perfluoroalkylethyl iodides to give terminal alkenes With perfluoroalkylpropyl iodides, however, replacement of iodine by nucleophiles predominates over the elimination reaction [71 (equation 1)... 

The resulting perfluoroalkyl iodides do not react with nucleophiles, such as OH, to be directly converted into FTOHs or PFCAs [4], As such, perfluoroalkyl iodides are reacted with ethylene to form perfluoroalkylethyl iodides ... 

Perfluoroalkylethyl iodides can then be readily converted to the corresponding FTOHs and PFCAs by hydrolysis [4],... 

The addition of solubilising groups has often much specificity for fluorinated surfactants. Thus, perfluoroalkylethyl iodides obtained by a telomerisation process (see above) can be converted into intermediates and surfactants described in a great number of patents and scientific literature. Some examples are shown schematically in Fig. 1.5. 

Figure 1.5 Some opportunities of fluorosurfactant synthesis from perfluoroalkylethyl iodides HO(CH2CH20)nCH3—CgF,50(CH2CH20)nCH3...

The perfluoroalkylethyl iodides can be readily converted to the corresponding alcohols, thiols, and sulfonyl chlorides used as intermediates for fluorinated surfactants (Fig. 2.6). 

A Hoechst process hydrolyzes 2-perfluoroalkylethyl iodides in N-methylpyrrolidone and water by heating at 150°C for 13 h [82]. An Asahi process... 

Fig. 2.6 Fluorinated surfactants derived from perfluoroalkylethyl iodides.

The hydrolysis of the perfluoroalkylethyl iodides is catalyzed by certain metals. Copper salts (e.g., cupric sulfate) catalyze the hydrolysis of perfluoroalkylethyl iodides in aqueous acetonitrile heated at 160°C for 12 h, followed by heating in 10% NaOH at 70°C for 2 h [85]. A Hoechst patent [86] describes a process for preparing 2-perfluoroalkylethanol by a reaction of the iodide in water containing a metal and a phase transfer agent in an acid medium (pH 1-6). Another Hoechst patent [87] discloses a reaction of 2-perfluoroalkylethyl iodide with a peracid to yield 2-perfluoroalkylethanol. 

Perfluoroalkyl iodides are converted with ethylene to perfluoroalkylethyl iodides, which can be oxidized more readily than the parent perfluoroalkyl iodides. Oxidation with chromic acid yields a perfluoroalkanoic acid and a fluorinated alkanoic acid with an a-methylene group [93,117] ... 

Perfluoroalkyl ethylene, CF3(CF2CF2) CH=CH2, obtained by dehalogena-tion of perfluoroalkylethyl iodide, is treated with ozone to give ozonides. Oxidative cleavage of the ozonides with hydrogen peroxide yields perfluoroalkanoic acids [132]. 

Perfluoroalkylethyl iodides can be converted to sulfonic acids utilizing a thiol as an intermediate. The thiol formed with thiourea [92-94] is dispersed in acidified water and oxidized with chlorine ... 

A fluorinated surfactant CF3(CF2) CH2CH2SOi"NH4 (NH4 or H ) is obtained by a reaction of the perfluoroalkylethyl iodide with KSCN. The thiocyanate formed is oxidized with a peroxycarboxylic acid (e.g., peracetic acid) [140] ... 

Ruorinated Bunte salts, featuring an —S2O3M group, are prepared by reacting sodium thiosulfate with perfluoroalkylethyl iodide [155,156] ... 

In a similar fashion, cationic fluorinated surfactants are prepared from telomer iodides by converting perfluoroalkylethyl iodides to sulfonyl chlorides and reacting these with A, A -dimethyl-l,3-diaminopropane [161]. 

The preparation of nonionic fluorinated surfactants from fluorinated alcohols is straightforward [218-230]. Perfluoroalkylethanol (see Section 2.3), obtained from telomer perfluoroalkylethyl iodides, is oxyethylated in the presence of a catalyst, for example, BF3 ... 

The toxicity of intermediates used for synthesizing fluorinated surfactants also has to be considered. The toxicity of perfluoroalkylethyl iodides depends on... 

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