Betaine and l-carnitine ester bromides: Synthesis and comparative study of their thermal behaviour and surface activity

Six esters of both betaine and l-carnitine bromides, featuring alkyl groups ranging from C8 to C18 in length, have been synthesized. The thermal behaviour of these twelve bio-based salts has been analyzed and compared by thermal gravimetric analysis and differential scanning calorimetry. The l-carnitine alkyl ester bromides melted below 100 °C and can hence be considered ionic liquids (ILs) with full rights. Conversely, the betaine alkyl ester...