Chemical Methodologies

Abstract In this study, a novel benzimidazole-based Brönsted acidic ionic salt, benzimidazolium dihydrogen phosphate, was synthesized and characterized using Mass spectrometry, FT-IR and NMR spectroscopy, as well as ICP analysis. The salt demonstrated efficient catalytic properties and reusability in the production of pyrano[2,3-d]pyrimidine and pyrano[3,2-c]chromene derivatives. Noteworthy advantages of this approach include the minimal catalyst requirement, straightforward work-up process, brief reaction duration, high yields, and catalyst reusability for four consecutive uses without a significant decrease in efficiency.

Abstract A new series of 1,3,4-oxadizole-containing azo derivatives were synthesized in this research. The structural properties of the newly-synthesized compounds were assessed by IR and ¹H- and ¹³C-NMR spectroscopic techniques. The antibacterial properties of the synthesized azo compounds were evaluated against Gram-negative and Gram-positive bacteria in vitro, revealing broader antibacterial spectrum on both bacteria groups for derivatives containing indole ring. In particular, most compounds had antibacterial effects on Staphylococcus aureus (ATCC 25923), while Pseudomonas aeruginosa (ATCC 27853) exhibited resistance against all azo compounds.

Abstract CO₂ emission resulting from rapid urbanization and industrialization is a significant contributor to global climate change, resulting from the burning of fossil fuels such as coal, oil, and natural gas. Approximately two billion tons of CO2 are released annually by all of the coal-fired power plants that are still in operation today. Various strategies that have been implemented to reduce CO₂ emissions includes energy efficiency, renewable energy, carbon capture and storage. Membrane technology has emerged as a promising solution for CO₂ capture and is currently being investigated for CO₂ capture from power plant emissions due to their fundamental engineering and cost effectiveness over competing separation technologies. This technology involves the use of selective membranes that allow the separation of CO₂ from gas mixtures such as flue gas, natural gas, and biogas. The performance of the membranes can be enhanced through the use of advanced materials, surface modification, and process optimization. The aim of this study is to review the literature on the recent advancements made in Membrane technology and its application in reducing CO₂ emissions from the past few years.

Abstract Representatives of the genus Scutellaria are perennial plants, which root extracts are widely used in oriental medicine, as they have a wide range of pharmacological effects on living organisms due to the presence of five flavones: chrysin, glucuronides – baicalein, wogonoside, and their aglycones – baicalein and wogonin. Scutellaria przewalskii Juz. is a poorly studied species of the Scutellaria family, a Tien Shan endemic. Reactive oxygen species (ROS) are produced under conditions of both biotic and abiotic stresses, which cause damage to cell structures. The aim of the present study was to examine the effect of ROS on the content of flavones, which may help uncover their role in protecting the root from damage. We used hairy roots of Scutellaria przewalskii. Hydrogen peroxide of two concentrations 1 and 10 mM was used as an inducer of oxidative stress. The highest flavones content was observed on the 1^st and the 7^th day of cultivation at 10 mM concentration of hydrogen peroxide. It was equal to 49.3 and 50.8 mg/g of dry weight respectively which was 1.9-3.0 times higher than the control sample. The change was caused by an increase in the content of glucuronides, primarily baicalin, suggesting its essential role in root adaptation to oxidative stress.