Wetting, foaming, and emulsification properties of novel methyltriphenylphosphonium carboxylate ionic liquid surfactants

Abstract

Novel methyltriphenylphosphonium carboxylate ionic liquid (IL) surfactants [Ph₃PCH₃][CH₃(CH₂)₆COO] (MTPP-O), [Ph₃PCH₃][CH₃(CH₂)₈COO] (MTPP-D), [Ph₃PCH₃][CH₃(CH₂)₁₀COO] (MTPP-L), [Ph₃PCH₃][CH₃(CH₂)₁₂COO] (MTPP-M), [Ph₃PCH₃][CH₃(CH₂)₁₄COO] (MTPP-P), [Ph₃PCH₃][CH₃(CH₂)₁₆COO] (MTPP-S) were synthesized via quaternization triphenylphosphine with dimethyl carbonate and anion exchange with different carboxylic acids successively. The structures of these IL surfactants were confirmed by FT-IR and ¹H-NMR. Meanwhile, the wetting, foaming, and emulsification properties of these IL surfactants were studied in this paper. The results revealed that methyltriphenylphosphonium carboxylate IL surfactants have lower foaming properties than quaternary ammonium salts with the same anionic units. And, these IL surfactants show better emulsification ability to soybean oil than that of liquid paraffin. Furthermore, contact angle results indicated that these IL surfactants have different wettability for parafilm and the contact angle increases at a higher concentration for MTPP-L, MTPP-M, and MTPP-P.

Graphical Abstract

Keywords:

• Methyltriphenylphosphonium carboxylate
• ionic liquid surfactants
• foaming properties
• emulsification
• wettability

Additional information

Funding

This work was financially supported by the National Key R&D Program of China (2017YFB0308900) and the Natural Science Foundation of Shanxi Province (201601D102023). And, this work also supported by JALA Research Funds (JALA 2016).