Synthesis, characterization and thermal properties of nine quaternary dialkyldiaralkylammonium chlorides

Nine R2R2′N+Cl− (R=benzyl, 2-methylbenzyl, 3-methylbenzyl, 4-methylbenzyl, 2-phenylethyl or 3-phenylpropyl; R′=ethyl or methyl) quaternary dialkyldiaralkylammonium chlorides were synthesized by treating dimethylformamide or diethylformamide with non-substituted or substituted arylalkyl (aralkyl) halide in the presence of sodium carbonate. The 1H NMR, 13C NMR spectroscopy, mass spectroscopy and elemental analysis were used to characterize the synthesized products. The crystal structures of six compounds were determined by X-ray single crystal diffraction. Four of the compounds crystallized in monoclinic space groups C2/c and P21/c (or P21/n), one in triclinic space group P−1 and one in orthorhombic space group Pbca. The powder diffraction method was used to compare the structural similarities between the single crystal and the microcrystalline bulk composition. Thermal properties of the new compounds were studied using TG/DTA and DSC methods. The decomposition of the compounds started generally between 130–185 °C and occurred without identifiable cleavages. The synthesized compounds do not seem to be suitable for ionic liquid applications because no melting point was observed for most of them. However, the good thermal stability of these compounds enables their potential use for example as phase-transfer catalysts and electrolytes.