Iranian Journal of Catalysis
Volume:12 Issue: 2, Spring 2022

The development of an appropriate kinetic model for cracking reactions is essential for simulation and process optimization. These results are to be potentially used for proper reactor design. The complexities of oil gas inlet combinations have led to an increase in the challenges while defining and depicting kinetics on an intrinsic scale. Hence, complicated chemical reaction circumstances are characterized by combining many possible pathways into more modest groups of comparable chemical substances. In addition, cracking kinetic demonstrations is frequently carried out in lumped forms. This is due to the complex nature of the feedstock, which is known to contain enormous hydrocarbon associated with series and parallel reaction networks. The representation of complicated compounds by consolidating a large chemical component into small amounts of apparent components has been generally utilized in industry to generate a straightforward approach to stoichiometry, thermodynamics, and kinetics. Considering the importance of this lumped method, this study focused on studying the development of a kinetic lump approach to solve kinetic problems and cracking mechanisms.

A novel organic-inorganic hybrid nanomaterial namely nano-[SiO2@R-Im-SO3H][CF3COO] (NSRISC) was synthesized, and characterized using FT-IR, EDS, FE-SEM, TGA and XRD analyses. Thereafter, the solvent-free production of bis-coumarins (from aryl aldehydes and 4-hydroxycoumarin) and N,N′-alkylidene bisamides (from aryl aldehydes and benzamide) was catalyzed by NSRISC. Bis-coumarins were produced in 86-97% at 100 ºC, and bisamides were obtained in 87-97% at 105 ºC. The reaction times were 15-30 min for both kinds of compounds.

Green chemistry has fostered research on recyclable, insoluble, and easily separable heterogeneous catalysts. Carbon materials are widely used for renewable energy and environmental studies. Here, we used green Pistachio peel, a biomass waste for the synthesis of magnetic carbon-based solid acid (Fe3O4@C-SO3H) by carbonization and sulfonation. The physicochemical properties of the nanocatalyst were characterized using XRD, FT-IR, FE-SEM, TGA, VSM, and TEM. The catalytic activity of Fe3O4@C-SO3H was investigated in the synthesis of isoxazole-5(4H)-one, 1-amido alkyl-2-naphthol, pyrano[2,3-c]pyrazole, and 2,3-dihydro quinazoline-4(1H)-one derivative, and some of the synthesized compounds were screened for their anti-microbial activity. Furthermore, the recovery and reuse of the catalyst were demonstrated six times without detectible loss inactivity. The concentration of H+ loaded on the Fe3O4@C-SO3H was reported to be 1.3 mmol g-1. The well-defined Fe3O4@C-SO3H core–shell heterostructures exhibited high stability, efficient recyclability (6 cycles).

Zinc Oxide nanoparticles (ZnONPs), which have well-known antimicrobial properties, are used extensively in various medical and general applications. In this analysis, 70-gram positive bacterial isolates were obtained from 100 patients using cardiac catheterization, with 54 Staphylococcus aureus and 16 other positive pathogenic bacteria. Accordingly, morphological, cultural and biochemical testes confirmed the results by VITEK 2 System. The synthesis of Zinc Oxide nanoparticles (ZnO NPs) was done using eco-friendly biological methods by Bacillus Subtilis filtrate which was identified and characterized by UV–Vis Spectrophotometer, SEM, AFM and FTIR, the pH value for the various of ZnONPS is about 7.1 and temperature 37 °C. Furthermore, the antibacterial efficacy of biological synthesized ZnO NPs against this isolated Staphylococcus aureus was determined. The results of SEM illustrated the morphology and sizes of ZnO NPs which are spherical and ovoid with the size range of 20-70 nm. The UV-Vis spectrum indicated the absorption bands of ZnO NPs at 378 nm. Antimicrobial susceptibility test was conducted for 54 isolates against 10 commonly-used antimicrobial agents using Kirby-Bauer disk diffusion method. The results of this study showed the highest rate of resistance against Amoxcillin/Clavulanic acid, Methicillin, tetracycline, Erythromycin and Azithromycin, and moderate resistance to Chloramphenicol. The synergistic effect of antibiotics (Amoxcillin / Clavulanic acid, Methicillin, tetracycline, Erythromycin, Azithromycin, Amikacine, penicillin G, Ampecilline, Trimethoprim\ sulphamethazole and Chloramphenicol) against Staphylococcus aureus was significantly increased in presence of ZnONPs compared to antibiotics only. Conclusion ZnO NPs demonstrate a good synergistic effect with antibiotics, which can open avenues for a future combination therapy against pathogenic bacteria.

A supported magnetic nanocomposite as a simple, stable, and efficient catalyst was successfully developed for condensation reaction of aldehydes, ammonium acetate, and isatoic anhydride to prepare 2,3-dihydroquinazolin-4(1H)-one derivatives as essential biologically active heterocyclic compounds. Ethanol as a non-toxic solvent under a reflux condition was utilized in the reactions. The Fe3O4/SiO2/CeO2 nanocomposite was prepared as a magnetic and novel catalyst. The value of components of the catalyst composite, including Fe3O4, SiO2, and CeO2, was optimized using experimental design to prepare the best catalyst composite with the highest reaction efficiency. The optimum amounts of Fe3O4, SiO2, and CeO2 in the catalyst composite were 0.37 g, 0.85 mL, and 1.28 g, respectively. The catalyst structure was characterized by FT-IR spectroscopy, vibrating sample magnetometer, Powder X-ray diffraction, and Transmission electron microscope. A sol-gel procedure was utilized to prepare the catalyst, in which chemical bonds between the catalysis components, leading to a high chemical, mechanical, and thermal stability of the catalyst. Several syntheses of 2,3-dihydroquinazolin-4(1H)-ones derivatives were performed using Fe3O4/SiO2/CeO2  (0.1 g) in EtOH (10.0 mL) under reflux for 9-19 min with yield in the range of 89-97%. The method displayed various advantages, including high yields, easy workup, low catalyst consumption, high catalyst reusability, low reaction times, and fast and straightforward catalyst separation using a magnet.

In the present paper, a novel thermal plasma method is proposed to synthesize ZnO-Fe2O3 nanocomposite, with different percentages of iron, namely 3, 5, and 7%. This method is an efficient feasibility of the Zno-Fe2O3 nanocomposite synthesis. The nanocomposites are synthesized by homemade direct current (DC) plasma torch. They are analyzed by different methods. The bandgap is determined by diffuse reflectance spectroscopy (DRS). The photocatalytic performance of Zno-Fe2O3 is evaluated. The results show that the structure of nanoparticles is spherical, which is more favored in the industry. Also, the particle size distribution is uniform. The average size of nanoparticle crystals increases with increasing iron content. Despite the formation of nanocomposites, due to the lack of support for nanoparticles, the results of photodegradation are not satisfactory.

This study is the first report of the application of sulfonated multi-walled carbon nanotubes (MWCNTs-SO3H) in the synthesis of tetrahydrobenzo[a]xanthene and tetrahydrobenzo[a]acridine derivatives. The catalyst was prepared via a chemical approach and the sulfonated groups were attached to the side-wall of MWCNTs with total density of 2.58 mmol.g-1. In order to prove functionalization of the MWCNTs-SO3H, the catalyst was characterized using FE-SEM, TEM, FT-IR, and Raman spectroscopy techniques. A three-component reaction including 2-naphthol, dimedone, and aromatic aldehydes were applied in the synthesis of tetrahydrobenzo[a]xanthene in the presence of 15.5 mol% of MWCNTs-SO3H under solvent-free conditions. Also, a four-component reaction including 2-naphthol, dimedone, aromatic aldehydes, and ammonium chloride was used in the synthesis of tetrahydrobenzo[a]acridine in the presence of 12.9 mol% of MWCNTs-SO3H under solvent-free conditions. All the derivatives of tetrahydrobenzo[a]xanthene and tetrahydrobenzo[a]acridine were obtained in good to excellent yields. The MWCNTs-SO3H was reused in seven consequent catalytic cycles without loss of their catalytic activity.

Mesoporous silica nanoparticles (MSNs) were synthesized hydrothermally and modified with Co2+ and Zn2+. The as-prepared samples were denoted as MSN, Co-MSN(X), and Zn-MSN(X), where X is the Si/M molar ratio. In addition, co-modified MSN samples with both cations were also prepared and denoted as Co-Zn(Y)-MSN(X), where Y indicates the Zn2+ content in the range of 1-7 wt.% relative to Co2+. Correctness of the anticipated structures was approved by FTIR, XRD, SEM, EDX, BET, and XRF analyses. It was found that Co-Zn(7)-MSN(75) can be used as an efficient photocatalyst for discoloration of basic red 5 under very mild conditions. Up to 86% of basic red 5 was discolored after 3.75 h under the optimized conditions including catalyst dosage of 0.025 mg mL-1, pH=7, and irradiation of 4×8 W UV (254 nm) lamps. By using the Langmuir–Hinshelwood kinetics model, it was found that the reaction followed a pseudo-first-order kinetic.

In the current study, a new methodology for the epoxidation of alkenes was developed. In this regard, the required ligand was synthesized from the reaction of isatin and 1,4-phenylenediamine to afford (3Z,3'Z)-3,3'-(1,4-phenylenebis(azaneylylidene))bis(indolin-2-one) ligand. Then, the two coordinate ligands were metallated using Cd and Mn/Fe/Co/Ni to obtain a series of hybrid dual metallic complexes containing (Cd and Mn/Fe/Co/Ni). The prepared complexes were characterized using FT-IR spectroscopy, UV-Vis spectroscopy, CHNS analysis, and magnetic susceptibility. Then, the prepared hybrid dual metallic complexes containing (Cd and Mn/Fe/Co/Ni) are used in the epoxidation of different alkenes to afford corresponding epoxides in moderate to good yields. The synthesized complexes were checked relative to recoverability and leaching of metal to the medium of the reaction.