Chemistry Journal of Moldova

https://doi.org/10.19261/cjm.2022.927   

 

Abstract (PDF)
Graphical Abstract: The paper presents original results on the of nitric acid concentrations effect on structure, morphology, protolytic properties and the activity of low-temperature carbon monoxide oxidation catalysts based on acid-modified phlogopite (Н-Phl-1) and K2PdCl4, Cu(NO3)2, KBr base components. The obtained samples were characterized by XRD, SEM, FT-IR spectroscopy and pH metric method. The obtained catalyst Pd(II)-Cu(II)/8H-Phl-1 can be recommended for use in respiratory devices. 

https://doi.org/10.19261/cjm.2021.912   

 

Abstract (PDF)
Graphical Abstract: The effect of halide ions (X= Cl⁻, Br⁻, I−) on the kinetics of ozone decomposition by compositions supported on the natural bentonite of the Dashukovske deposit in Ukraine (N-Bent(D)) has been studied. The obtained results have shown that the activity of the KX/N-Bent(D) composition in the ozone decomposition reaction increases in the row KCl << KBr < KI, which correlates with an increase in their reducing properties (the redox potential of the Х₂/2Х⁻ pair decreases). Such catalyst compositions can be recommended for applying in personal protective equipment for the respiratory system.


 

https://doi.org/10.19261/cjm.2022.895   

 

Abstract (PDF)
Graphical Abstract: A facile, one-pot, and solvent-free synthesis was developed to obtain a thermally stable chitosan biopolymer. The bifunctional isocyanate by interaction with chitosan formed urea and urethane bonds between chitosan chains. Subsequently, the designed chemistry facilitated the formation of carbodiimide bonds between chitosan chains via dehydration of the urea bond. The modified chitosan was proved to be superior in thermal properties and could be used as a thermally stable bio-filler. This synthetic methodology is a facile route to achieve improved thermal stability in biopolymers.

 

https://doi.org/10.19261/cjm.2021.902   

 

Abstract (PDF)
Graphical Abstract: An environmentally friendly method for phosphogypsum processing into N,Ca,S,P-fertilizers is proposed. Thus, was obtained a complex liquid N,Ca,S,P-fertilizer with the content of nutrients (% wt.) N:Ca:S:P = 56:26:12:6 in the dry product, and 16.8:3.6:7.8:1.8 in the liquid phase. The obtained fertilizer increased the yield of radish by 7.16% compared to the control. The advantage of the proposed method is reducing the cost of the fertilizer, increasing its nutritional value, and obtaining useful products from the waste.


 

DOI: https://dx.doi.org/10.19261/cjm.2021.859   

 

Abstract (PDF)
Graphical Abstract: On the basis of a new model of chemical dissolution, an analysis of the kinetic parameters obtained using the modified V.V. Dolivo-Dobrovolsky equation was carried out. It shows that the change in parameters during the transition from one mineral to another is subject to a compensation effect. Additionally, calculations based on the new dissolution model made it possible to distinguish between the systemic and individual properties of minerals of the same nature in the process of dissolution. These minerals differ from each other by the concentration of ac tive surface complexes, and are combined into a system by a single transmission coefficient and the same value of the lifetime of the active complex.
  

https://doi.org/10.19261/cjm.2022.928   

 

Abstract (PDF)
Graphical Abstract: Four new {Cr₈} rings have been synthesized and characterized; they are all based on the classic [CrF(O₂CtBu)₂]₈ ring 1. Three routes have been studied. The first is direct synthesis, by reacting hydrated chromium(III) fluorides with the acid; this has been used to produce  [CrF(O₂CEt)₂]₈ 3. The second route uses 3 as a precursor and substitute with an incoming carboxylate. This has been used to make [CrF(O₂CCCl₃)₂]₈ 4 and [CrF(O₂CC₆F₅)₂]₈ 5. The third route uses 
N-ethyl-D-glucamine (H₅Etglu) as a template and produces chiral rings [Cr₈F₄(Etglu)(O₂CtBu)₁₅] 6. The single crystal X-ray structures of these new compounds are reported.


 

https://doi.org/10.19261/cjm.2021.864   

 

Abstract (PDF)
Graphical Abstract: In this work, the stereospecific synthesis of optically active cis β-lactams under diverse microwave-induced conditions using diverse solvents was reported. The effects of low tanδ values of the solvents are found to be more crucial than solvents with high dipole moments and dielectric constants. The results indicated that for the synthesis of β-lactams solvents with low tanδ and high dipole moment and high dielectric constant are necessary. Best of the knowledge this is the first report that examined the importance of tanδ values of the solvents in β-lactams synthesis.

 

Abstract (PDF)
Graphical Abstract: The detailed mechanism of the interaction of the radical cation ABTS^•+ with a number of food acids (gallic, ferulic, caffeic, vanillic, cinnamic, syringic, p-coumaric) is revealed by means of the DFT calculations. It is shown that the interaction between the neutral molecules of the studied food acids and ABTS^•+ does not lead to any charge transfer from these molecules onto ABTS^•+. The almost complete conversion of the ABTS radical cation into its diamagnetic derivative occurs due to the interaction of one of the sulphonic groups of ABTS^•+ with the acid anions through the formation of the corresponding intermolecular hydrogen bond.