Journal of Saudi Chemical Society最新文献

The use of biomass as a renewable, sustainable, and eco-friendly energy source is now widely recognized as a potential solution for a variety of environmental problems. To develop biodiesel production, cost-effective feedstocks such as agricultural waste, food waste, and non-edible/waste cooking oil were utilized. A heterogeneous solid base catalyst was synthesized by calcining a mixture of waste golden apple snail shell (Pomacea canaliculata) and cultivated (Musa sapientum) banana peel. In transesterification process, potassium oxide (K₂O) derived from banana peel is used as a cocatalyst to improve the catalytic activity of calcium oxide (CaO) catalyst derived from waste shell. The innovative CaO-K₂O catalyst was investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF) and the Brunauer-Emmett-Teller (BET) technique. The morphology and elemental composition of calcium (Ca), potassium (K), and oxygen (O) in the catalyst were validated by field emission-scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX). The CaO catalyst exhibited a BET surface area of 10.88 m²/g, which was enhanced to 14.62 m²/g upon combination with K₂O. The Hammett indicator of CaO catalyst fell between 7.2 < H_< 9.8. However, the CaO-K₂O catalyst exhibited a higher value of 15.0 < H_< 18.4, which could be attributed to the phase transition from CaO to CaO-K₂O. To investigate the effects of catalyst concentration, ethanol/oil molar ratio, and transesterification time on the yield of fatty acid ethyl ester (FAEE). The optimal conditions for FAEE synthesis were determined using a central composite design (CCD) approach with response surface methodology (RSM). The regression equation obtained for the CCD model has a determination coefficient (R²) of 0.9921, indicating that this model is well-fitted. At 3.69 wt% catalyst concentration, 19.48:1 ethanol/oil molar ratio, and 1.80 h transesterification time, the highest FAEE yield from Jatropha Curcas oil (JCO) of 97.06 % was obtained. The novel catalyst has a strong yield and can be utilized for up to 6 cycles. It was found that the corresponding yield was 90 % when employing the same process parameters, demonstrating the high reusability of this catalyst. The biodiesel produced from non-edible JCO meets the criteria for standard biodiesel (ASTM D-6751 and EN 14214). The CaO-K₂O catalyst is inexpensive, easy to make, biodegradable, recyclable, and environmentally friendly because it is derived from a biological residue. Because of these characteristics, it may be an appropriate candidate for the role of “green catalyst” in sustainable energy production.

A highly efficient diazotization of diazoacetates with para-quinone methides has been established via a tetrabutyl ammonium bromide (TBAB)-catalyzed 1,6-conjugated addition pathway. This methodology affords a convenient, safe, and rapid way to generating diverse polysubstituted α-diazocarbonyl compounds, displaying good functional group tolerance, high atom economy, and easy accessibility.

In this article, Persea americana aqueous peels extract was used to synthesize silver nanoparticles in a simple and environmentally friendly manner. The properties of synthesized silver nanoparticles (AV-AgNPs) were studied via several techniques, including UV–vis spectroscopy, DLS, TEM, EDX, and FTIR. The UV–Vis spectra analysis revealed that the highest absorption peak occurred at 428 nm, providing strong evidence for forming AV-AgNPs. The TEM results indicate that the synthesized AV-AgNPs were uniformly dispersed, exhibiting a spherical shape with an average size of 24 nm. EDX imaging also confirmed the presence of AgNPs. FTIR analysis shows P. americana's phenolic compounds and proteins significantly contribute to AV-AgNP synthesis and stabilization. In addition, the antimicrobial activity of AV-AgNPs was assessed against pathogenic bacteria commonly found in humans, exhibiting a moderate zone of inhibition against the selected pathogens. Additionally, AV-AgNPs were used in antioxidant studies with the robust antioxidant properties 2, 2 diphenyl-1-picrylhydrazyl (DPPH). In vitro studies have shown that AV-AgNPs can remarkably inhibit α-amylase in a dose-dependent manner, indicating their potential as antidiabetic agents. In silico research, it was revealed that naringenin derived from P. americana exhibited a strong binding to S. typhi and B. cereus (−8.7 and −7.5 kcal/mol, respectively). At the same time, quercetin demonstrated a high binding affinity and energy to α-Amylase (−8.9 kcal/mol). This study presents the first investigation into the biosynthesis of AgNPs utilizing the aqueous peel extract derived from P. americana with multiple uses, including antioxidant, antimicrobial, and antidiabetic activity.

The photocatalyzed cleavage of cycloketoximes is a promising approach for modifying their biological activity and designing prodrugs activated by light. Cycloketoximes containing a cyclic ring structure that can hinder their degradation and modification in biological systems. Photocatalysis offers a sustainable and efficient method for breaking down the cyclic structure using a photocatalyst and exposure to ultraviolet light. These reactions are initiated by iminyl radicals, that gain access to distal-carbon through selective C–C cleavage. This process provides a solution for the challenging task of modifying the biological activities of cycloketoximes. Moreover, it can also be useful for selectively removing protecting groups from organic molecules or cleaving specific chemical bonds, thereby facilitating organic synthesis.This review article covers synthetic uses of photocatalyzed cleavage of cycloketoximes and highlights its ongoing research in the field of photocatalysis.

In this research, zeolite ZSM-12 with Si/Al ratio = 80 was synthesized by hydrothermal method. The synthesized zeolite ZSM-12 was modified using Fe and Ga metals and a combination of these two metals, 1 % iron metals (Z80-Fe) and 1 % gallium metals(Z80-Ga), and a 2 % combination of these two metals (Z80-Fe-Ga). The physicochemical properties of synthesized zeolites were evaluated and compared by XRD, EDX-dot-mapping, NH3-TPD, BET, FT-IR, and TGA analyses. The catalytic assessment of synthesized zeolites in the HTO (n-hexane to olefins) process in a fixed bed reactor under atmospheric pressure and Weight hourly space velocity (WHSV) equal to 4 h⁻¹ at 550 °C was evaluated. Various parameters such as selectivity towards light olefins, propylene to ethylene (P/E ratio), production of light alkanes, and aromatic compounds (BTX) were investigated. The results show that using metals led to the improvement and adjustment of the acid sites of zeolite, and the highest amount of light olefin and the lowest amount of coke were obtained. The result of the n-hexane to olefin process showed that the yield of light olefins was significantly improved in all modified catalysts compared to parent zeolite MTW. Compared to other modified zeolites, Z80-Fe-Ga zeolite has the highest yield of light olefins, equal to 59 %. This zeolite performs better due to the presence of gallium and iron metals and shows the highest propylene selectivity (P/E = 2.4). In addition, according to the results of the TGA analysis, the content of coke on the Z80-Fe-Ga catalyst after the catalytic reaction is much less than that of other catalysts after the catalytic reactor test.

In this study, magnetic graphene oxide (MGO-Fe₃O₄) nanocomposite was prepared by co-precipitating of FeCl₃.6H₂O and FeCl₂.4H₂O on waste battery-derived graphene oxide and used as an adsorbent for the efficient removal of As(III) from aqueous solutions. The prepared nanocomposite was characterized by Fourier transformed infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, zeta potential, and a vibrating sample magnetometer. These characterizations revealed that spare like Fe₃O₄ nanoparticles (10.5 nm) were decorated on graphene oxide nanosheets and showed excellent saturation magnetization (89.73 emu/g). The adsorption of As(III) by MGO-Fe₃O₄ was optimized by analyzing various parameters. Experiments showed that 98 % of As(III) was removed at neutral pH in a just 20 min, even though the adsorbent dose was only 0.14 g/L. The adsorption kinetic and isotherm were best fitted with the pseudo-second order kinetic and Frendlich isotherm model. The maximum adsorption capacity (q_max) was found to be 50.2 mg/g at room temperature. Thermodynamic studies showed that the As(III) adsorption process was spontaneous and exothermic in nature. The enhanced adsorption capacity and magnetic properties of MGO-Fe₃O₄ are crucial in the drinking water treatment process due to the easy magnetic separation of MGO-Fe₃O₄ from aqueous solution after the adsorption process. Density Functional Theory (DFT) was also used to investigate the interaction between MGO-Fe₃O₄ and As(III), which further suggested that MGO-Fe₃O₄ and As(III) mostly interact with each other through surface complexation and hydrogen bonding.

The release rate and time are very important for the drug carriers, silica aerogel filled hydroxypropyl cellulose/chitosan (SA/HPC/CS) composites were fabricated for the release of 5-fluorouracil (5-Fu), and the release rate and time were regulated with the content of SA, pH value and external coating material. Firstly, the 5-Fu loaded SA/HPC/CS composites and Eudragit L100 coated composites were prepared with cross-linking followed by freeze-drying, and characterized by SEM, FTIR, XRD, DSC, and TG. Then, the effect of SA content on the encapsulation efficiency of SA/HPC/CS@5-Fu was investigated, and 5-Fu release behavior under different pH values from these aerogel composites was evaluated with four kinetic models. In addition, to further solve the abrupt effect of the obtained composites, Eudragit L100 coated SA/HPC/CS@5-Fu was fabricated, the sustained release behavior revealed that the coating technique can effectively improve the release behavior and extend release time.

Water pollution caused by textile dyes is considered a major and growing issue. To address this challenge, in this research, water-stable Cu-MOFs/GO composite catalysts were produced using the hydrothermal synthesis method as an efficient persulfate (PDS) activator for methyl orange (MO) degradation. We also explored the changes in surface morphology, crystal structure, surface functional groups, and valence states of the materials before and after the introduction of GO by Cu-MOFs. It was shown that Cu-MOFs/GO demonstrates a more stable surface structure, and the unique folded structure of GO provides a better hydrophobic environment for Cu metal cluster hence making MOF easier to grow. The Cu-MOFs/GO-PDS system showed a high activation performance on persulfate in a wide pH range (3–11), meanwhile, was less affected by the presence of natural anions in the environment and more inhibited by natural organic matter citric acid. Furthermore, the Cu-MOFs/GO had excellent stability, reusability and structural integrity, and the removal rate of MO was maintained after five cycles. In terms of oxidation mechanism, in addition to the generation of ·SO4⁻ and OH· radicals, there were also singlet oxygen ¹O₂ and active Cu(III) in the system, and all of these active substances contributed to the removal of pollutant MO.

The target compounds 4-(((1H-heteraryl)imino)methyl)-N,N-bis(4-(((4-((4-nitrophenyl) diazenyl)phenyl)imino)methyl)phenyl)aniline (7a-q) were prepared starting with 4,4′-diformyltriphenyl amine (2) which subjected to react with N-bromosuccinimide to give bromodiformyltriphenyl amine (4). Compound 4 reacted with two moles of 4-nitro-4′-aminoazobenzene to give the di-Schiff base 5. Compound 5 converted to its corresponding formyl derivative 6 by reaction with n-BuLi. The reaction of the formyl derivative 6 with seventeen amino heteraryl compounds afforded the target compounds 7a-q. All the newly prepared compounds were characterized by different spectroscopic and elemental analyses. Compounds 7a-q were screened for their antimicrobial activities against yeast-like fungi (C. albicans), Gram-negative (GN) bacteria (P. aeruginosa and E. coli), and Gram-positive (GP) bacteria (S. thuringiensis and B. subtilis). Compounds 7d, 7k, 7l, and 7q showed the highest activity against Gram-positive bacteria. The results of antimicrobial activity showed that it is highly affected by the used amine basicity.

Facilitating energy resource deficiency and environmental contamination, this work focuses on sustainable biodiesel production through the esterification reactions of oleic acid (OA) with methanol. To address the reaction, a novel heterogeneous acid catalyst, 12-tungstophosphoric acid (TPA) immobilized on Sn-based MOFs (Sn(II)-BDC) was synthesized via a simple, green solvent, and easy-to-implement synthesis strategy for the first time, and applied effectively for esterification process of OA to produce biodiesel. The structure and composition of as-obtained catalyst have been verified using XRD, FTIR, N₂ physisorption, SEM, EDX, TG, Py-FTIR, TPD-NH₃, and XPS techniques. The obtained TPA/Sn(II)-BDC catalyst was found to be the best with 60 wt% of TPA loading, which resulted in an OA conversion of 91.7 % at optimized conditions of 0.15 g catalyst loading and methanol to OA molar ratio of 20:1 at temperature of 120 °C in 4 h, and the excellent performance arises from available pores structure, large amounts of acidic sites, good stability and the synergistic catalytic effect of TPA and Sn(II)-BDC. Furthermore, the composite catalyst reusability has been studied for five cycles, and it exhibits an acceptable conversion. This research provides a green and large-scale synthesis route for the sustainable production of biofuels by constructing heteropolyacids/Sn-based MOFs synergistic catalysts.