Iranian Journal of Catalysis
Volume:14 Issue: 1, Winter 2024

In the past decade, numerous longitudinal studies have explored green chemistry and its applications in nanoparticle synthesis due to the toxicity associated with traditional methods. Among the various techniques for nanoparticle synthesis, the use of plant extracts in green synthesis has recently gained significant popularity. Green methods are particularly suitable for large-scale nanoparticle synthesis, offering faster preparation rates compared to microorganisms and the ability to produce nanoparticles in diverse sizes and shapes. Nickel oxide nanoparticles (NiO NPs) have been extensively utilized in catalysis, photocatalysis, optics, magnetism, and antibacterial applications. This review focuses on the preparation of NiO NPs using plant extracts, emphasizing their advantageous features such as the absence of contaminant release, environmental friendliness, and cost-effectiveness. Additionally, we delve into the catalytic, photocatalytic, and antibacterial applications of NiO NPs.

Magnetic nanoparticles (MNPs) were treated with dodecyl sulfate (DS) and dodecanol (DO) to enhance their affinity for lipids. Various methods, such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometery (VSM), thermal gravimetric analysis (TGA), and FTIR spectroscopy were employed to analyze and characterize these modified MNPs. The functionalized MNPs were employed to adsorb different types of oils (edible, motor, and diesel oils). MNP@DO and MNP@DS exhibited oil absorption capacities of up to three and two times their own mass for edible oil, respectively. The complete repulsion of water was evident, and a rapid interaction between lipophilic magnetic catalysts and oil on the water’s surface was observed. These oil-absorbing catalysts could be efficiently removed by employing an external magnet, and they demonstrated excellent reusability. The findings indicate that these novel catalysts exhibit substantial oil-absorbing capabilities and can be used as low-cost and effective technique for oil/solvent-spill cleanups.

Favipiravir (FVP) was one of the promising medications for the treatment of Covid-19 patients. There are limited studies on the electrochemical performance of FVP. Hence it is interesting to study the electrochemical detection of FVP by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry. The G/In2O3 nanocatalyst was prepared by precipitation method and applied on the pencil graphite electrode by drop-cast method, the electrode represented here as G/In2O3/MPGE and used as a working electrode for the detection of FVP in a pH 7 Britton Robinson (BR) buffer. The oxidation signal was seen in the region of 1.0 to 1.23 V. The predicted linear range is between 0.7 to 4.9 μM. The corresponding limit of detection (LOD) and limit of quantification (LOQ) were found for pure drugs at 0.28 μM and 0.93 μM, whereas for samples in commercial tablets, it is 0.23 and 0.79 μM. The same in the presence of urine medium is 0.30 and 106 μM, respectively. The developed G/In2O3/MPGE offers good detection, selectivity, reasonable stability, and reproducibility to detect FVP in pure drug, tablet form, and in the presence of urine.

One of the industries that uses huge volumes of water is the textile sector, which generates a lot of wastewaters. Electrocoagulation (EC), an environmentally friendly method, has been utilized to remediate textile dyeing effluent. The goal of this work is to compare the catalytic activity of Ti with Al using two sets of experiments (Al-Ti, Ti-Al), one of which contains Al as an anode and in the other Ti as an anode to treat textile dyeing effluent to reduce operating costs of the process as Ti electrode undergoes uniform dissolution with less energy consumption compared to Al. The maximum color removal efficiency (CRE) of 97.13% and 96.8% was obtained while using Al-Ti and Ti-Al electrodes. The removal efficiency of Total Dissolved Solids (TDS), Total Suspended Solids (TSS), and Chemical Oxygen Demand (COD) were also found to be comparable with both electrodes. The FTIR analysis of treated water demonstrated that the pollutant removal was similar in both electrodes. The generation of hydroxides during the EC process is demonstrated by XPS examination of sludge, with Al appearing as Al2p in the +3-oxidation state and Ti appearing as Ti2p1/2 and Ti2p3/2 in the +4-oxidation state. The operating cost calculated for Al-Ti and Ti-Al electrodes was found to be 2.90 US and 0.87 US. The difference in operating cost between these two electrodes was found to be 70%. The energy, electrode consumption, and operating cost for the Al-Ti electrode were found to be high due to its high dissolution.

Levulinic acid (LA) is a valuable renewable resource that can serve as a versatile biomassderived building block for the synthesis of organic chemicals, providing a sustainable alternative to depleting fossil fuel resources. Catalytic esterification of LA with alcohol yields levulinate esters, which find numerous applications including perfumes and fuel additives. In this study, the performance of Indion 190 as a solid acid catalyst was investigated for the esterification of LA with n-butanol to produce n-butyl levulinate (BL). The effects of reaction time, catalyst loading, temperature, and molar ratio of LA to butanol were examined One Factor at a Time (OFAT) to optimize levulinic acid conversion. The highest conversion of LA, which was 92.59%, was attained with a reaction time of 6 hours at 100 ◦C, utilizing a catalyst loading of 1.25 wt% Indion 190 for a molar ratio (LA: butanol) of 1:8. In the kinetic study of the reaction, an activation energy of 65.5 kJ/mol was obtained. Indion 190 proved to be a promising, cost-effective solid acid catalyst for the production of levulinate esters, providing an eco-friendly pathway for the continuous production of butyl levulinate.

Cu-catalysis was employed to create numerous (E)-5-bromo-N-aryl oxindole nitrones with satisfactory to excellent coupling efficiencies. This process involved the reaction of N-unprotected 5-bromoisatin-3-oximes with aryl-boronic acids under moderately reactive conditions. Remarkably, the reaction exhibited tolerance towards various aryl-boronic acids containing diverse functional sensitivity subgroups (73% to 97% yields and 2 to 6 h). Extensive research has demonstrated that the (C=O) group present in 5-bromoisatin-3-oximes can serve as an inhibitory molecule or ligand, playing a crucial role in the generation of (E) oxindole nitrones.

As a natural-based catalyst, nano-Fe3O4@dextrin/Si(CH2)3/DABCO was fabricated and characterized with different analytical methods such as field emission scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray mapping, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and vibrating sample magnetometer. The mentioned new natural magnetic nanocatalyst was employed for the three-component synthesis of tetrahydrobenzo[b]pyrans and spirooxindoles from aromatic aldehyde or isatin, malononitrile, and 1,3-dicarbonyl compounds in green media for the required time. The major advantages of these protocols include atom economy, short time of reaction, simplicity of operation, lack of toxic solvents, excellent yields of products, easiness of separation, and reusability of the catalyst.

In this work, an efficient method for the construction of N-amino-2-pyridone analogs was performed using the condensation of aldehyde, malononitrile and cyanoacetohydrazide through Fe3O4@aminopropyltriethoxysilane-terephthaldehyde-melamine (Fe3O4@APTES-TA-MA) as an efficient recyclable magnetic covalent organic framework nanocatalyst in ethanol at reflux conditions. Fe3O4@APTES-TA-MA was characterized via FT-IR, EDS, SEM, TEM, VSM, and TGA methods. The average size of the nanoparticles was found between 40-90 nm. Clean procedure, short reaction time, and high efficiency are some benefits of this protocol. Also, the nanomagnetic catalyst can be reused five times without significant loss of its activity.