Journal of the Iranian Chemical Society最新文献

This study investigates the combined effects of UV/TiO₂ and UV/H₂O₂ processes on the degradation of 1,2-dichlorobenzene in aqueous media, employing a recycled current photo-reactor equipped with a water jacket. Evaluation of various factors—initial pH, TiO₂ dosage, initial H₂O₂ concentration, pollutant concentration, and temperature—contributed to the optimization of degradation rates and operational costs for both processes. For the degradation of 50 mg/L of DCB, the optimal operating conditions were found to be for UV/TiO₂: pH = 3, [TiO₂] = 30 mg/L and T = 25 °C, and for UV/H₂O₂: pH = 3, [H₂O₂]₀ = 350 mg/L and T = 25 °C. After 60 min of irradiation time, the degradation efficiency, pseudo first order rate constant and operational cost value for the UV/TiO₂ and UV/H₂O₂ processes were as 98.9%, 0.0771 min⁻¹, 11.6 $/m³ and 96.3%, 0.0573 min⁻¹, 11.8 $/m³ respectively. Also, thermodynamic parameters of activation energy, enthalpy change, entropy change and standard Gibbs free energy were calculated as 21.78 (kJ/mol), 19.37 (kJ/mol), − 0.20 (kJ/mol K) and 73.34 (kJ/mol at 25 °C) for UV/TiO₂ process and 7.62 (kJ/mol), 5.18 (kJ/mol), − 0.25 (kJ/mol K) and 80.14 (kJ/mol at 25 °C) for UV/H₂O₂ process. The investigation also encompassed the exploration of 13 hybridization scenarios, including UV/TiO₂/H₂O₂ and UV/H₂O₂/TiO₂, revealing notable findings. Notably, a specific hybridization scenario, namely UV/TiO₂ (30 mg/L)/H₂O₂(250 mg/L), demonstrated a significant synergistic effect (29.5%). Evaluating pollutant mineralization unveiled compelling results, with approximately 85% mineralization achieved after 90 min for the UV/TiO₂(30 mg/L)/H₂O₂(250 mg/L) scenario, showcasing a remarkable synergism (44%) in the mineralization process.

Graphical abstract

Crystal structure analysis and DFT computational calculation of two symmetrical and unsymmetrical decahydroacridine-1,8-diones (DHACs) were carried out to elucidate the effect of the aryl-substituted heterocyclic core in these compounds on the comparative bond lengths, bond, and dihedral angles. According to these findings, the central heterocyclic ring in these compounds is exhibited in the pseudo-boat conformation, in which the aryl substitution occupies the pseudo-axial position. Moreover, the fused outer rings were in the twisted half-chair conformation. The weak and strong inter- and intramolecular interactions between the suitable donor–acceptor positions (N‒H···O, C‒H···O, H‒N···H and C‒H···π of the C=C double bond) in symmetrical and enantiomeric pairs of unsymmetrical DHACs affect the orientation of the molecules in the crystal packing. The relative contributions of various intermolecular interactions in these compounds are evaluated using Hirshfeld surface analysis. The DFT calculations were performed to outline the optimized structure, molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs), natural bond orbital (NBO) and to elucidate the effect of the space orientation of the attached aryl ring toward the heterocyclic ring on the total energy content of DHAC 2. Additionally, MEP analysis in DHAC 2 revealed that the negative electrostatic potential is more concentrated around the O₁-atom of the C₁=O₁ double bond than the O₂-atom of the C₁₃=O₂ double bond. The results of the NBO analysis demonstrated that in the crystal packing of compounds 1 and 2 the strongest intermolecular interaction occurs from the LP(2)O₂ to σ*(N₁–H) and LP(1)O₁ to σ*(N₁‒H), respectively.

3-Methyl indanones are key synthetic building blocks for a variety of natural and useful synthetic compounds. Their synthesis is exceedingly difficult. Herein, we described a palladium (II) mediated intramolecular one-pot redox-relay cyclization of aromatic homoallylic alcohols to cyclic keto compounds. This catalytic system enabled direct conversion of homoallylic alcohols to corresponding indanones (3-methyl-1-indanones). Homoallylic alcohols were synthesized by reacting allyl magnesium bromide with corresponding aromatic aldehydes. The optimized reaction yielded up to 88% 3-methylindanones. Our findings enabled us to device a plausible mechanism for this one pot reaction.

Graphical Abstract

Fluorescent tiny molecules that are resistant to acid have long been the center of interest. The nitrogen atoms on benzyl cyanide were sp hybridized, while the two nitrogen atoms at pyrimidine were sp² hybridized in the primary structure that we constructed. With the addition of a protonic acid (H₂SO₄, CH₃SO₃H, and HF), the nitrogen atoms at acridine underwent sp³ hybridization, which caused the hydrogen protons to interact with the three types of nitrogen atoms to varying degrees. This distribution of the electron cloud density led to a decrease in fluorescence emission. Furthermore, Gaussian 09 software and DFT calculations were used to model its orbital conformation, which is the highest occupied molecular orbital—lowest unoccupied molecular orbital (HOMO–LUMO). Furthermore, its crystal structure was assigned to the orthorhombic system with stronger non-homogeneity (a = 8.9160 (4) Å, b = 44.289 (3) Å, c = 9.6131 (7) Å, α = 90°, β = 90°, γ = 90°, V = 3796.0 (4) ų, z = 4, Dc = 1.244 g/cm³).

Graphical abstract

In the photo-oxidation processes, the oxidants play a vital role in removing color. However, a comprehensive comparison of the three common oxidants’ performance for color removal from textile wastewater has not been conducted. Also, the effect of periodate in the presence of ferrous for color removal has not been investigated extensively. The object of this study was to evaluate and compare the effect of three common oxidants on the removal of color. Central composite design was employed to design the experiments and evaluate the interaction between parameters and their impact on color removal. The photo-oxidation processes were carried out under UV light irradiation (60 W) in the presence of ferrous (Fe²⁺) and three oxidants, namely hydrogen peroxide (H₂O₂), sodium persulfate (SPS), and sodium periodate (SPI). The four main variables were the reaction time, the pH value, the concentration of oxidants, and the concentration of ferrous. Finally, the optimal values for all parameters were shown and these three processes were compared with each other. Although the UV/SPI/Fe²⁺ process had the highest color removal (96%), by considering all parameters, the UV/SPS/Fe²⁺ was a better choice because of its high efficiency, low reaction time, and low oxidant concentration. The results suggested that the photo-Fenton process could not be a good option among these processes, as it required the longest reaction time and highest oxidant concentration while achieving the lowest removal efficiency (82%). The results of this study can help with the decision-making process to select a better process for textile wastewater treatment.

The reaction of Ru₃(CO)₁₀(µ-Ph₂AsCH₂AsPh₂) and arsine ligand (AsPh₃) afforded a new triruthenium cluster derivative, Ru₃(CO)₉(µ-Ph₂AsCH₂AsPh₂)(AsPh₃) (1). 1 was synthesised and characterised by elemental analysis, Fourier transform infrared, ¹H nuclear magnetic resonance (NMR) and ¹³C{¹H} NMR spectroscopy. The molecular structure of 1 was confirmed by single crystal X-ray diffraction (SXRD) analysis. The compound features a bidentate ligand of Ph₂AsCH₂AsPh₂ and a monodentate ligand of AsPh₃ that occupy the equatorial positions at Ru atoms. The thermal decomposition of 1 investigated by the thermogravimetric-differential thermogravimetric (TG-DTG) technique involves three stages, with the final product being Ru atoms with a residual rate of 18.60% (calcd: 18.41%). Density functional theory (DFT) calculations were performed using the B3LYP hybrid exchange–correlation functional method, and the LanL2DZ pseudopotential on Ru with 6-31G basis was set for all other atoms. Assessment of bond lengths and angles between SXRD and DFT data demonstrated consistent values within expected ranges. Frontier molecular orbitals analysis and molecular electrostatic potential were also illustrated. The 2D fingerprint plot of Hirshfeld surface analysis reveals that H···H contact dominates the population with 38%. The interplay of intermolecular C–H···O hydrogen bond and C–H···π interactions were found to be effective in stabilizing the molecular structure.

The paper assesses batch system microcrystalline cellulose (MCC) adsorptive ability for copper and iron uptake from aquatic environment. Field emission scanning electron microscope (FESEM), point zero charge and Fourier transform infrared (FTIR) spectroscopy were used to examine the physicochemical and morphological features of MCC. The batch system of the sequestration progression for the elimination of Cu(II) and Fe(II) was used by varying the solution pH, MCC doses, initial copper and iron concentration, and resident time. The maximum removal percentage for Cu(II) and Fe(II) were 99.5% and 96.4%, respectively, at pH 7. The influence of MCC dosage showed the 1.0 g/L of adsorbents results the highest percentage of Cu(II) (99.8%) and Fe(II) (88.63%) correspondingly. Equilibrium data for both metals were well fitted with both Langmuir and Freundlich isotherms, representing monolayer and multilayer adsorption systems. The maximum sorption capacity of MCC was 534.61 mg/g and 845.75 mg/g, respectively, for Cu(II) and Fe(II) ions at room temperature. Pseudo-second-order model best describes the copper and iron kinetic data, signifying the dominance of chemisorption adsorption relation between the negatively charged MCC and adsorbates. After four successive regeneration cycles, the MCC polymer maintained its maximal adsorption capacity, demonstrating effective copper and iron ion separation from aqueous solution. According to the study’s findings, poisonous heavy metals can be successfully removed from aquatic environments using eco-friendly microcrystalline cellulose.

Supercapacitors are one of the most unique energy storage devices with high efficiency. Supercapacitors are known as renewable sources and replace batteries. This research presents the making of a new generation of supercapacitors in a simple method with high specific capacity and the property of maintaining specific capacity in long and multiple cycles based on polyaniline and carbon cloth fibers with graphene oxide. This nanocomposite is characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and thermogravimetric analysis. The electrode made of this nanocomposite has a specific capacity of 420 F g⁻¹, and after 1000 cycles, it retains more than 83% of the specific capacity, which reaches 348.6 F g⁻¹ at a current density of 1 A g⁻¹. The improvement of retention of specific capacity in the presence of graphene oxide compared to the absence of graphene oxide is more than 10%. This electrode, by maintaining its specific capacity in many cycles, has obtained a significant advantage over other electrodes. These results show that the electrode based on carbon cloth fibers/polyaniline/graphene oxide (CFs/PANI/GO) nanocomposite can be a high-performance and environmentally friendly electrode.

The Pt/HZSM-5-(KCC-1, KIT-6, and SBA-3) catalysts were successfully used for the isomerization reaction of n-heptane. These catalysts were used to optimize this process at response surface methodology combined with central composite design. The effects of temperature, contact time, and flow rates of n-heptane and hydrogen, as some important variables, on the response (reaction rate) were studied. The analysis of variance gave a significant quartic model with good accuracy for estimating the reaction rates for these catalysts. The optimum conditions were obtained for the Pt/HZSM-5-SBA-3 catalyst at a temperature of 350 °C, contact time of 6 h, an H₂ flow rate of 20 cc min⁻¹ and an n-C₇ flow rate of 2 cc h⁻¹ with a reaction rate of 5.7 mol g⁻¹s⁻¹. The modeling results also showed that both the power law and Langmuir–Hinshelwood models agreed with the data obtained from catalytic performance (R² > 0.9). The results show that the Pt/HZSM-5-SBA-3 catalyst has the lowest activation energy (13.64 kJ mol⁻¹) and the highest reaction rate. The reaction order for hydrogen is in the range of − 0.03 to − 0.25 and that for n-C₇ is 0.88–1.19.