Fluorinated pyridinium and ammonium cationic surfactants

• Partially fluorinated pyridinium and ammonium cationic surfactants are described.
• The fluorinated chains are interrupted by CH2 or O groups.
• Aqueous surface tension and foaming of select candidates are comparable to commercial benchmarks.

New classes of partially fluorinated cationic surfactants, including pyridinium sulfonates and ammonium hydrochlorides have been prepared in which a fluoroalkyl chain is interrupted either by ether oxygen (O), or by methylene (CH2) units. These surfactants are obtained from multi-step syntheses via intermediate fluoroalkyl ethylene iodides (RfO(CF2CF2)nCH2CH2I, Rf = C3F7, C2F5,n = 1–3 or Rf(CH2CF2)m(CH2CH2)n, Rf = C4F9, C6F13m = 0–2, n = 1–2) or fluoroalkyl iodides (RfI, Rf = C3F7O(CF2CF2)3I, C6F13). The surface activities of these fluorinated cationic surfactants were examined and compared to commercially available fluorinated cationic surfactants used as additives in oil field applications. Some examples demonstrated good performance relative to controls yet are more fluorine efficient because they have lower fluorine content than their perfluoroalkyl analogues. For the ammonium hydrochlorides, the effect of different spacer groups between the cation and the fluorinated chain including ethylene, butylene and isopropylidene on surface activity was also examined.

Syntheses of partially fluorinated pyridinium and ammonium cationic surfactants containing methylene (CH2) or ether (O) groups are reported. The aqueous surface tension reduction and foaming properties of these surfactants are also described.Figure optionsDownload as PowerPoint slide