An activated carbon (AC) with a high surface area of 4320.7 m²/g was synthesized via the chemical and thermal processing of walnut residues. The resulting activated charcoal was characterized by various techniques, including Brunauer–Emmett–Teller (BET) surface area analysis, scanning electron microscopy (SEM), and IR spectroscopy. The prepared activated carbon was studied for its capacity to adsorb CO₂ gas. When exposed to CO₂ for 60 min in a closed chamber at atmospheric pressure at 25 °C, the adsorption of a notable 301.1 mmol CO₂ (13.25 g CO₂) per gram of activated carbon was observed.

The ionic liquid (IL) (1-methyl-4-ethyl pyridine-1-ium iodide) [MEPy]I in this work was created through a direct reaction between 4-ethyl pyridine and methyl iodide. Subsequently, complex salts were prepared using Lewis acids (ferrous chloride and copper chloride) in molar ratios of 1:1 and 1:2, ionic liquid: metal chloride. Nuclear magnetic resonance spectroscopy 1H-NMR, elemental analysis (CHN), infrared spectra FT-IR, and other methods were used to identify the prepared compounds. Moreover, the study of the thermal stability of the prepared compounds. These compounds were tested in the extractive desulfurization process (EDS). Using a model oil sample containing dibenzothiophene (DBT) as an aromatic organosulfur compound dissolved in solvent (n-decan) at a concentration of 1500 ppm. The sulfur percentage was estimated before and after treatment by gas chromatography technique GC-FID, and the conditions were determined (time and concentration of the extracted substance), as it was found that ionic liquids of pyridine base and its complex salts with ferrous and copper chlorides have good efficiency in the process of removing sulfur (EDS).

Two new ligands, methyl 4-amino antipyrinyl dithiocarbamates (MAC) and benzyl 4-amino antipyrinyl dithiocarbamates (BAC), were synthesized from 4-amino antipyrine and corresponding methyl or benzyl halides with potassium hydroxide in dimethylformamide. Then they were coordinated with five divalent transition metals: M = Mn, Co, Ni, Zn, and Cu(II) to produce ten novel complexes, [M(MAC)2]Cl2 I(a-e) and [M(BAC)2]Cl2 II(a-e), which were characterized by some physical properties and spectral methods, elemental analyses, molar conductance, and magnetic susceptibility, in addition to 1H NMR, FT-IR and UV-Vis. Spectroscopy proved that all metal complexes I(a-d) and II(a-d) have octahedral geometries, except those of copper complexes (Ie) and (IIe), which have square planer geometry (D4h). Following screening for biological activity against Gram-positive bacteria (Streptococcus pyogenes) and Gram-negative bacteria (Pseudomonas aeruginosa), the results of these novel complexes' investigations showed no effect except the complexes of [Zn(BAC)2]Cl2 II(a), [Zn(MAC)2]Cl2, I(a), [Mn(MAC)2]Cl2, I(b) and the ligand (MAC) are given promising data. KEY WORDS: 4-Amino antipyrine, Dithiocarbamates, Dithiocarbamate complexes, Biological activity Bull. Chem. Soc. Ethiop. 2025, 39(3), 447-457. DOI: https://dx.doi.org/10.4314/bcse.v39i3.5

The thermodynamic constants and thermal stability of recently synthesized alkyl imidazolium iodide ionic liquids (ILs) and their complex salts with transition metal Lewis acids are examined in the present study. Using NMR, UV-Vis spectroscopy, and conductivity measurements, the ILs—more especially, 1,3-diallyl imidazolium iodide [AAIm]I (S1) and 1-allyl-3-methyl imidazolium iodide [AMeIm]I (S2) were produced and characterized. These ILs were reacted in a 2:1 ratio with transition metal chlorides (Mn(II), Fe(II), Co(II), Ni(II), and Cu(II)) to form their complex salts. Thermal analysis shows that each substance is stable underneath 100 °C and that decomposition occurs across phases. Activation energy, enthalpy, entropy, and Gibbs free energy were among the thermodynamic parameters calculated using the ASTM 1641 standard and the Coats and Redfern model. KEY WORDS: Ionic salts, Thermodynamic kinetic models, Complex salt decomposition, Thermodynamics parameters Bull. Chem. Soc. Ethiop. 2025, 39(12), 2447-2457. DOI: https://dx.doi.org/10.4314/bcse.v39i12.6