Trifluoroacetic anhydride functionalizing alcohol groups

A recent study has further proven the applicability of gas-phase reactions to functional groups at the monolayer surface. Alcohol terminal groups were quantitatively converted to trifluoroacetates by exposure to the vapours of trifluoroacetic anhydride (equation 7). Reaction with perfluoropropionic and perfluorobutyric anhydrides proceeded similarly, but with ca 80% yield (XPS). Very high contact angles (>120°) of perfluoro-terminated layers proved the formation of esters333. 

Three methods that were used to measure the chemical changes associated with oxidative degradation of polymeric materials are presented. The first method is based on the nuclear activation of lsO in an elastomer that was thermally aged in an, 802 atmosphere. Second, the alcohol groups in a thermally aged elastomer were derivatized with trifluoroacetic anhydride and their concentration measured via 19F NMR spectroscopy. Finally, a respirometer was used to directly measure the oxidative rates of a polyurethane foam as a function of aging temperature. The measurement of the oxidation rates enabled acceleration factors for oxidative degradation of these materials to be calculated. 

Alcoholic functional groups in HFAs can be derivati-zed using a trifluoroacetic acid anhydride (TFAA)-pyridine mixture after esterification of the carboxylic function. Methyl iodide (CH3I) can be used for preparation of the methyl esters of HFAs. 

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