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Ammonium dinitramide (ADN) is one of the potential oxidants in solid propellant formulations because it is environmentally friendly, has a high specific impulse, and has minimum signature exhaust gases. ADN was synthesized through the nitration reaction of potassium sulfamate salt with a mixture of sulfuric acid and nitric acid. The optimal conditions for the synthesis were studied, such as the ratio of components, reaction temperature, and reaction time. Specifically, the nitration reaction temperature was -40 oC, the ntration reaction time was 30 minutes, the molar ratio of potassium sulfamate, sulfuric acid, and nitric acid was 1, 2.5, and 9, respectively, and the molar ratio of potassium dinitramide to ammonium sulfate of 1: 1.1.

Multi-drug resistance to antibiotics represents a growing challenge in treating infectious diseases. Outside the hospital, bacteria with the multi-drug resistance (MDR) phenotype have an increased prevalence in anthropized environments, thus implying that chemical stresses, such as metals, hydrocarbons, organic compounds, etc., are the source of such resistance. There is a developing hypothesis regarding the role of metal contamination in terrestrial and aquatic environments as a selective agent in the proliferation of antibiotic resistance caused by the co-selection of antibiotic and metal resistance genes carried by transmissible plasmids and/or associated with transposons. Efflux pumps are also known to be involved in either antibiotic or metal resistance. In order to deal with these situations, microorganisms use an effective strategy that includes a range of expressions based on biochemical and genetic mechanisms. The data from numerous studies suggest that heavy metal contamination could affect the dissemination of antibiotic-resistant genes. Environmental pollution caused by anthropogenic activities could lead to mutagenesis based on the synergy between antibiotic efficacy and the acquired resistance mechanism under stressors. Moreover, the acquired resistance includes plasmid-encoded specific efflux pumps. Soil microbiomes have been reported as reservoirs of resistance genes that are available for exchange with pathogenic bacteria. Importantly, metal-contaminated soil is a selective agent that proliferates antibiotic resistance through efflux pumps. Thus, the use of multi-drug efflux pump inhibitors (EPIs) originating from natural plants or synthetic compounds is a promising approach for restoring the efficacy of existing antibiotics, even though they face a lot of challenges.

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