Nylon trifluoroacetylation

N,N -Bis-(trichloroacetyl)-nylon 6,6 and N,N-bis-(trifluoroacetyl)-nylon 6,6 are prepared by the reaction of the corresponding substituted acetic anhydride with nylon 6,6 These trihalogenoacetyl polyamides are readily soluble in chlorinated hydrocarbon solvents, dioxane, tetrahydrofuran and DMSO. 

N J -Bis(trifluoroacetyl)-nylon 6,6 has been used for the trifluoroacetylation of amines and alcohols The reactions have been carried out in acetonitrile. In the course of the reaction, nylon 6,6 prec itates and can be separated by filtration. The correqjonding trifluoroacetylamides ate isolated in 41-96% 3delds. Trifluoroacetylation of alcohols proceeds in good yields The selectivity of this trifluoroacetylating agents to various substituted anilines and against structurally isomeric secondary amines has been studied in detail by kinetic measurenents. 

Also, when Nylon 6,6 is reacted with trifluoroacetic anhydride, trifluoroacetyl nylon forms ... 

Size exclusion chromatography (SEC) of semicrystalline polyamides, polyesters with high melting point, and certain fluoropolymers is reviewed in this chapter. Because of their semicrystalline nature, polyamides are hard to dissolve in common chromatographic solvents. The SEC of nylons, or different types of polyamides with strong intermolecular H bonding, is reviewed based on the types of solvents in which they are soluble. These solvents are high-temperature m-cresol (neat or blended with other solvents), certain common solvents after trifluoroacetylation of the polymers, and fluorocarbon solvents, such as trifluoroethanol and hexafluoroisopropanol. The merits and limitations of each solvent systems are discussed here. 

For the molecular weight measurement of any polymers by SEC, the first requirement is that the polymers or its derivatives be soluble in a chromatographic solvent. Of the different types of nylons, only a few noncrystalline aliphatic polyamides are soluble in common solvents. The majorities of aliphatic polyamides, however, are soluble in common solvent only after trifluoroacetylation (2). A literature search did not find any work related to aromatic polyamides, and therefore they are not included here. 

Most recent work has concentrated on developing low-temperature procedures and solvents. These include, in particular, hexafluoroisopropanol (HFIP) as a room-temperature solvent, as well as trifluoroacetylation of the nylon to assist its dissolution [63].-... 

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