Synthesis, physicochemical and antimicrobial properties of novel imidazolium based ionic liquids

Abstract

Most of the research groups are now focusing on deep eutectic solvents due to the lack of biodegradation of ionic liquids (ILs), these liquid salts first emerged as promising and alternative “green” solvents for volatile organic solvents. Ionic liquids have a wide variety of applications with interesting and appealing properties because of various cation and anion combinations that expand their application either as antimicrobial agents, lubricant, and additives. The essence and importance of ILs is continuously being evaluated especially for the industrial applications and some ILs have not yet been synthesized or metathesized, and with their properties not fully evaluated. Herein, a series of novel imidazolium based ILs were synthesized using the metathesis method and characterized to determine their acidity, moisture, and thermal stability. Their physicochemical properties showed that [1-allyl-3-methylimidazolium] [TFO] is the most thermally stable compound according to the DSC/TGA analysis, and Karl Fisher analysis was used to determine the content of water. The acidity levels of the ILs determined by using a Hammett’s Acidity function revealed Ho values in the range of 3.9861 to 4.2857. The photocatalytic degradation process revealed that 1-allyl-3-methylimidazolium salicylate [Amim] [SaL] was still present after 72 hours. Microbial susceptibility testing of the ILs against selected Gram-positive and Gram-negative bacteria using agar well diffusion method revealed diverse degrees of susceptibility of the test organisms, with Pseudomonas aeruginosa ATCC BAA 1744 and Escherichia coli ATCC 11775 being the least and most sensitive to all the treatments, respectively.