Synthesis, Characterization and Properties of New Lauryl Amidopropyl Trimethyl Ammoniums

A new lauryl amidopropyl trimethyl ammonium methyl carbonate with the formula CH 3 (CH 2 ) 10 CONH(CH 2 ) 3 N + (CH 3 ) 3 CH 3 CO 3 − was synthesized via a high pressure process with tertiary amines and dimethyl carbonate, and its chemical structure was confirmed using 1 H-NMR spectra, mass spectral fragmentation, and FTIR spectroscopic analysis. In addition, several quaternary ammonium salts with new counterions X − (X − =HCO 3 − , HCOO − , CH 3 COO − , CH 3 CH(OH)COO − ) were also synthesized by the ion exchange reaction of methyl carbonate quaternary ammoniums with corresponding acids. The surface activities of these compounds were measured, including surface tension (γ), critical micelle concentration and minimum surface area ( A min ) at 25 °C. Adsorption and micellization free energies of these quaternary ammonium salts in their solutions showed a good tendency towards adsorption at interfaces. The antimicrobial activities are reported for the first time against representative bacteria and fungi for lauryl amidopropyl trimethyl ammoniums. It was found that the antimicrobial potency was Gram-positive bacteria > fungi > Gram-negative bacteria.