_____________________________________________________________________________________________________ *Corresponding author: E-mail: kumarajoy.cu@gmail.com; Asian Journal of Physical and Chemical Sciences 5(1): 1-9, 2018; Article no.AJOPACS.39148 ISSN: 2456-7779 Synthesis and Characterization of Ammonium Benzoate and Its Derivative Based Ionic Liquids and Their Antimicrobial Studies Md. Ismail Hossain 1 , Ajoy Kumer 1* and Sayeda Halima Begum 1 1 Ionic Liquid Research Laboratory (ILRL), Department of Chemistry, University of Chittagong, Chittagong 4331, Bangladesh. Authors’ contributions This work was carried out in collaboration between all authors. Authors MIH and SHB designed the study, performed the statistical analysis, wrote the protocol. Author AK wrote the first draft of the manuscript, managed the analyses of the study and the literature searches. All authors read and approved the final manuscript. Article Information DOI: 10.9734/AJOPACS/2018/39148 Editor(s): (1) Luigi Casella, Professor, Department of Chemistry, University of Pavia, Pavia, Italy. Reviewers: (1) Sarbani Pal, MNR Degree and PG College, India. (2) Rohit L. Vekariya, Ton Duc Thang University, Vietnam. Complete Peer review History: http://www.sciencedomain.org/review-history/23203 Received 1 st December 2017 Accepted 9 th February 2018 Published 15 th February 2018 ABSTRACT Nowadays, Ionic Liquids (ILs) have been developed as a cleaner, safer and environmentally friendly chemicals that are widely used in both academia and industries. The ammonium benzoate and its derivative ILs were synthesized in the neutralization reaction of different cations of diethylamine with benzoic acid, 3-chlorobenzoic acid, 3-methylbenzoic acid and 3-nitrobenzoic acid. The reaction was monitored by thin layer chromatography. The synthesized compounds were purified. Then the synthesized ILs was characterized by FT-IR Spectroscopy and 1H Nuclear Magnetic Resonance (NMR) Spectroscopy. Antibacterial screening of the test 20% ILs was carried out with six human pathogenic bacteria, such as Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeroginosa and Shigella dysenteriae using the well-diffusion technique for 50 µL each well and show good antimicrobial activity. To establish the relative study of antimicrobial activity of ILs, 20 µL of sample solution of the concentrations 1000 mmol/L, 500 mmol/L and 100 mmol/L respectively were added to each well of the petri plate. The ILs showed the maximum zone Original Research Article