Perfluorocarboxylic esters, from

A novel procedure, illustrated in Scheme 11, involves the interaction between a metal dialkyl phosphite and the phosphonium perfluorocarboxylate formed from a Wittig reagent and a perfluorocarboxylic anhydride (Rf = CF3 or C2F5). Although alkenylphos-phonic diesters are important coproducts in yields which approach 50%, useful yields of the (l,2-epoxyalkyl)phosphonic diester 128 (also up to 50%) are obtainable when both R and R are Me, but the formation of epoxyalkylphosphonic esters fails completely when R R = (CH2)4 ... 

If esters arc perfluorinated the main products are perfluoroalkanes or perfluoroacyl fluorides byproducts are carbon dioxide and oxygen difluoride. The acyl and the alkyl groups in the ester give perfluorocarboxylic acids.41 A comparison of the results obtained from butyl acetate and ethyl butyrate, and from butyl propionate and propyl butyrate, indicates that perfluoro-butanoic acid is obtained in better yield from ethyl and propyl butyrate than from butyl acetate and butyl propionate. Thus, perfluorocarboxylic acids are formed more readily from the acyl than from the alkyl group of the ester. 

Simply changing the solvent in the Pd-based catalytic system from water to a mixture of water and a perfluorocarboxylic acid (some water is necessary for the reaction see Scheme 6) had no significant effect on product composition formic acid was still the principal product from methane. However, the addition of Cu or Cu chloride to the reaction mixture had a dramatic effect. Methanol and its ester now became the preferred products, with virtually no acetic and little formic acid being formed [40 b]. The activation parameters for the overall reaction determined under the condition when the rate was first order in both methane and carbon monoxide were A = 2 X [O sfa = 15.3 kcal mol . Since methyl trifluoro-acetate is both volatile and easily hydrolyzed back to the acid and methanol, it should be possible to design a system where the acid is recycled and methanol is the end product. Lee and co-workers have recently reported on the further characterization of the catalyst in this bimetallic Pd/Cu system [41]. 

Perfluorocarboxylate polymers in the carboxylic methyl ester, potassium salt and carboxylic acid forms were analysed by FTIR transmission and ATR spectroscopies. Band assignments were made for most of the dominant peaks. An absorbance band ratio, comparing the 555/cm C-F band to the 982/cm C-O-C ether band, was found to be a direct measure of the equivalent weight of the polymers. In addition, the transition from the methyl ester form to the acid form was determined by examining the 2969/cm methyl ester band versus the broad 3200/cm band. Quantitative expressions were presented for use in the computation of equivalent weight and acid content based on the FTIR thin film absorbance measurements. The technique used provided a direct measure of the trade-off... 

Poly(l,l-dihydroperfluoroalkyl acrylates) are obtained in the following manner Aliphatic carboxylic acids are fluorinated electrochemically. The resulting perfluorocarboxylic acids, CF3(Cp2)jcCOOH, are hydrogenated in the form of their acyl chlorides or esters, and the resulting 1,1-dihydroper-fluoroalcohols are esterified with acrylyl chloride. The monomers are polymerized with K2S2O8 in aqueous emulsion. Oil-resistant elastomers result from vulcanization of these polymers with sulfur/triethylene tetramine. Poly(l,l-dihydroperfluorobutyl acrylate) and poly(3-perfluoromethoxy-l,l-dihydroperfluoropropyl acrylate) are commercially available. 

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