Chemical Papers最新文献

Polycyclic aromatic hydrocarbons are one among the strenuous problems of indemnity of hydrosphere brought on by the unintended release of refractory chemicals into the environment. Naphthalene has been removed from aqueous solution using various adsorbents, such as activated carbon, graphene oxide, etc in yesteryears. This study describes the synthesis of nanocellulose from rice husk and its application for the removal of naphthalene from simulated wastewater. To characterize the synthesized nanocellulose, SEM, TEM, BET, FTIR, XRD, zeta potential, AFM, TGA, DSC, and EDX techniques were used. The nanocellulose surface area was 1.152 m² g⁻¹. The experiments were conducted in batch mode to investigate the impact of various operating conditions on naphthalene adsorption. Maximum removal of naphthalene was at pH 2 within 150 min. The experimental data were subjected to various models, viz., thermodynamic, kinetic, and isotherm models. Error analysis confirmed that the pseudo second-order equation and Langmuir model fitted well to the experimental data. The maximum removal of the naphthalene was ~80%. The desorption and reusability efficiency of nanocellulose was also evaluated. According to this study, nanocellulose has a higher potential for naphthalene removal due to the presence of active sites.

A series of symmetric methylenebisphenols based on sesamol (1), 2-methoxybenzene-1,4-diol (2), eugenol (3), carvacrol (4), and thymol (5) was synthesized using the condensation reaction between these phenols and paraformaldehyde. We carried out a comparative evaluation of the antioxidant properties of both parent compounds 1–5 and the products derived from them. The conversion of sesamol (1), eugenol (3), and thymol (5) to the corresponding methylenebisphenols is associated with a significant increase in the antioxidant activity (AOA) of the synthesized compounds, measured by the degree of inhibition of Fe²⁺/ascorbate-induced fatty acid oxidation of mouse brain lipids. The derivatives are superior to the original natural phenols in terms of their ability to improve the survival of red blood cells (RBCs) of lab mice and protect their hemoglobin from oxidation under the conditions of hemolysis induced by 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) or hydrogen peroxide. In terms of several parameters, the activity of the synthesized products exceeded that of the synthetic antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT).

Graphical abstract

In this investigation, the new organic dyes (TDBR1–TDBR6) have been designed from a moiety, namely thienobenzodithiophene (TDB), using the density functional theory (DFT) approach. The dyes were analyzed to predict their absorption spectra (λ_max), optimized geometries, optical features, density of states, electrostatic potential surfaces with solar cell parameters. It was determined that how electron-donating and electron-withdrawing groups could be affixed with molecules to affect their charge transfer (CT) as a Pull–Push phenomenon. All the new dyes demonstrated a significant Pull–Push effect having maximum absorbance (λ_max) 677–691 nm. Furthermore, the analysis of their bond lengths with respect to their planarity patterns indicated a facile CT patterns. All the new dyes also possessed higher LUMO energies (E_LUMO) than TiO₂ oxide conduction band while they have binding energy (E_b) range of 0.20–0.54 eV. The linear polarizability (< α >) values for all the designed dyes were recorded to be 0.77–1.87 × 10^–21 e.s.u, while their first-order polarizability (β_tot) and second-order hyperpolarizability (γ_tot) were ranged to be 2.21–3.81 × 10^–25 and 13.8–29.3 × 10^–30 esu. Also their computed dipole moments (µ_tot) were in accordance with their NLO responses having their ranges (0.14–7.65 D). The global reactivity parameters had a direct relationship with NLO qualities. They showed their ionization potential values to 0.63–1.87 eV while their softness values (σ) 0.18–1.08 eV. The higher NLO parameters were seen with a reduction in HOMO–LUMO gaps (HLG) which stated that a dye molecule with a lower HLG value might supposed their global reactivity to be softer, less stable, and much more reactive. Their light harvesting efficiency (LHE), with TDB as donor material, was also very promising (−2.8–1.24) having an ON state for dyes TDBR3–TDBR6. Finally, before synthesis, determining material characteristics using DFT will aid in understanding their projected behavior for their applications like NLO and/or as organic dyes.

The study focuses on laboratory testing of carbon-dioxide adsorption. It compares three methods used to determine the capacity of the adsorbents proposed for CO₂ capture. The tests have been performed on two samples, namely natural clinoptilolite and a 13X molecular sieve. Two methods were dynamic and one was static. The first dynamic method evaluated the capacity based on the change in CO₂ volume fraction before and after a fixed-bed adsorber. For the same purpose, the second dynamic method used a gravimetric procedure. The static method detected a change in pressure during CO₂ adsorption. The capacities determined for carbon-dioxide mole fractions of 5, 10, 13 and 20% at temperatures of 30 and 40 °C at atmospheric pressure were compared. The apparatus with a fixed-bed adsorber made it possible to perform tests also for overpressures of 2 and 5 bar and lower temperatures. The capacity obtained on the three apparatuses showed good agreement. The maximum capacity (3.32 mmol g⁻¹) was determined for the 13X sample at 10 °C and a partial CO₂ pressure of 120 kPa and, conversely, the lowest (0.12 mmol g⁻¹) for clinoptilolite at 40 °C and a partial CO₂ pressure of 5 kPa. There was no significant difference in capacity standard deviations between the apparatus (0.014–0.036 mmol g⁻¹). The fixed-bed apparatus required one to three orders of magnitude more gas for the experiment and was more challenging to operate and evaluate the data.

Economically speaking, rodents possess a serious threat to the agriculture sector. One of these organisms that directly threaten agriculture, stocks, and others is the Norway rat, Rattus norvegicus (R. norvegicus). The 2-cyano-N-(1H-1,2,4-triazol-3-yl) acetamide (1) was used as a precursor to give 2-cyano-3-(dimethylamino)-N-(1H-1,2,4-triazol-3-yl) acrylamide (2) and ethyl 2-amino-5-cyano-1,6-dihydro-6-oxo-1-(1H-1,2,4-triazol-3-yl) pyridine-3-carboxylate (3). Infra-red, ¹H-NMR, ¹³C-NMR, MS, and elemental analysis were done for the precise structure elucidation of the applied synthons. The prepared compounds were tested as potential rodenticides against the Norway rat, Rattus norvegicus. Toxicity analysis using four serial doses of both prepared compounds revealed that the LD₅₀ values were 160.6 and 391.7 mg/kg body weight, for ethyl 2-amino-5-cyano-1,6-dihydro-6-oxo-1-(1H-1,2,4-triazol-3-yl) pyridine-3-carboxylate (3) and 2-cyano-N-(1H-1,2,4-triazol-3-yl) acetamide (1), respectively. Several biological variables, such as alanine transaminase (ALT), aspartate transaminase (AST), serum urea, creatinine, and total protein, have been assessed and evaluated as biological response indicators. Analysis revealed a highly significant increase in both AST, ALT, urea, and creatinine levels, while the total protein level showed a considerable reduction in treated rats exposed to 2-cyano-N-(1H-1,2,4-triazol-3-yl) acetamide (1) and ethyl 2-amino-5-cyano-1,6-dihydro-6-oxo-1-(1H-1,2,4-triazol-3-yl) pyridine-3-carboxylate (3) when compared to the control treatment. Liver histological examination showed structural changes in the form of congestion in the central vein, necrosis in some hepatic regions, and pyknotic nuclei, while kidney histological examination showed vacuolar degeneration of the epithelial cells of some convoluted tubules and the disappearance of some glomeruli and other marked atrophies. Necrosis in some areas was noticed. Field application through bait consumption took place with a satisfactory reduction of 68.4% for ethyl 2-amino-5-cyano-1,6-dihydro-6-oxo-1-(1H-1,2,4-triazol-3-yl) pyridine-3-carboxylate (3), while it was 61.9% for 2-cyano-N-(1H-1,2,4-triazol-3-yl) acetamide (1) when compared to the recommended Zinc phosphide commercial rodenticide that poses an 81% reduction.

Graphic abstract

Acer Truncatum Bunge is a woody plant of the maple family unique to China that produces oil containing 5‒7% nervonic acid, which has various uses in medicine. This work demonstrates the extraction of nervonic acid ethyl ester from the oil of this plant using urea inclusion. In the case of the urea inclusion solid, there is no new peaks found in SEM image and just a superposition of those expected peaks representing urea and fatty acid ethyl esters can be observed, indicating that the interaction force between urea and fatty acid ethyl esters was just intermolecular forces rather than chemical reaction. A 95% ethanol solution was determined to be the optimum solvent for this process. Urea inclusion was found to separate various fatty acid esters with decreasing efficiency in the order of lignoceric acid > behenic acid > arachidic acid > stearic acid > nervonic acid > palmitic acid > erucic acid > cis-11-eicosenoicacid > oleic acid > linoleic acid > linolenic acid. In the optimized process, ethyl esters of cis-11-eicosenoicacid, oleic acid, linoleic acid and linolenic acid were removed from the oil via a two-stage urea inclusion mechanism that also removed sterols and other substances. Ethyl esters of arachidic acid, behenic acid and lignoceric acid were subsequently separated through a third-stage urea inclusion step. After six extractions, the product contained erucic acid and nervonic acid ethyl esters with a nervonic acid ethyl ester proportion of 52.4%. Characterization by infrared spectroscopy confirmed that the product was free of residual urea.

Coordination compounds of Co(II), Ni(II), Cu(II) and Zn(II) ions were synthesized from the ligands (E)-2-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)thiosemicarbazone(HL¹)/(E)-2-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)-4-methylthiosemicarbazone(HL²)/(E)-2-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)-N-(4-ethylphenyl)thiosemicarbazone(HL³)/(E)-2-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)-N-(3-fluorophenyl)thiosemicarbazone(HL⁴) which were derived by condensing 1,3-diphenyl-1H-pyrazole-4-carboxaldehyde with derivatives of thiosemicarbazide. The characterization of synthesized compounds was carried out by numerous analytical and spectral techniques, i.e., FT-IR, ¹H NMR, ¹³C NMR, mass spectrometry, UV–Vis, SEM, ESR, powder XRD. Spectral studies illustrated that thiosemicarbazones are bonded through (NS) atoms with central metal ions conforming octahedral geometry of the complexes. The endothermic and non-spontaneous degradation pathways of the compounds were illustrated by TG–DTA studies. The in vitro antioxidant and anti-inflammatory activities were performed by DPPH and BSA assay, respectively, and the results suggested that the complexes 13, 14 having IC₅₀ values 2.08–2.01 μM and exhibited good radical scavenging power and complexes 13, 14, 16 showed good inflammation inhibition power with IC₅₀ values 8.88–10.85 μM. The in vitro antimicrobial activity was screened against S. aureus, B. subtilis, E. coli, P. aeruginosa, C. albicans, R. oryzae microbial strains, and the complexes 13, 14, 20 showed more efficiency with MIC values ranging from 0.0066 to 0.0067 μmol/mL. The overall biological activities advocate complexes 13 and 14 as compelling drugs for infectious ailments. Additionally, the recommended structure of the compounds (HL³) (3) and [Ni(L³)₂(H₂O)₂] (14) have been used to examine the most favored mode of interaction between protein and compounds via molecular docking study with Chromosome partition protein Smc (PDB ID:5H67). The main aim of this research work is to invent multifunctional medicinal drugs that include investigating the roles of pyrazole, thiosemicarbazides and transition metal complexes.

Graphical abstract

In this study, the corrosion efficacy of microwave-assisted Soxhlet extract of pomegranate (Punica granatum L.) peels as a corrosion inhibitor of mild steel S240 in a 3.5% NaCl solution was explored. The inhibition of corrosion was comprehensively evaluated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and mass loss measurements. The results demonstrated that the extract achieved a maximum inhibition efficiency of 93.34% at a mass concentration of 800 ppm. The formation of a protective layer on the metal surface was provided through the use of EIS, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The molecular characterization of the adsorbed species was carried out by high-performance liquid chromatography (HPLC) in combination with electrospray ionization mass spectrometry (ESI-MS). To gain insights into the mechanism of action and the nature of the adsorption sites, the experimental findings were compared with theoretical predictions obtained through density functional theory (DFT) and Monte Carlo simulations.