Catalysis Surveys from Asia最新文献

Ionic liquids (ILs) have overcome solutions to problems associated with increased production with sustainable green approaches over the last three decades. Ionic liquids have appeared as a significant alternative to traditional organic solvents in metal-catalyzed reactions in organic synthesis. This substitution has proven to be instrumental in promoting sustainable development goals by facilitating an eco-friendlier approach to chemical synthesis. Carbon- carbon (C–C) cross-coupling reactions have a decisive role in organic and inorganic chemistry, acting as a flexible tool for the synthesis of complex molecules and materials. These reactions find their applications in various fields, including natural products, pharmaceuticals, and polymers. Among the most frequently used methods for C–C bond formation are the Heck and Suzuki reactions. In this review, we have examined and discussed the recent advancements in the use of ILs as solvents and catalysts in Heck and Suzuki reactions. We have explored various factors such as conversion, yield, catalyst recovery, and time reaction in the context of these reactions over the past few decades. The advantages and accomplishments of using ionic liquids have been evaluated with respect to their potential for enhancing the efficiency of industrial processes.

Cheese whey effluent (CWE) is a byproduct from cheese making industry having a high (50,000–100,000 mg/L) chemical oxygen demand (COD) which makes it mandatory to treat this effluent. Unlike the traditional methods known for CWE treatment – fermentation, enzymatic hydrolysis, ultrafiltration, etc., aqueous-phase reforming (APR) is a technology which helps to treat the wastewater by valorising it producing high heating value gases such as hydrogen (H₂), thus achieving a double benefit. In this work, APR of lactose as a model compound from CWE was carried out using a Pt promoted Ni/Htlc catalyst (where Htlc refers to hydrotalcite) in a stirred batch reactor. Experimental trials were performed where the reaction parameters viz. temperature (488–518 K), catalyst loading (2–6 kg/m³), reaction time (1.5–6 h) and lactose concentration (1–5 wt%) were optimized. For optimized parameters, H₂ selectivity of 73% was achieved. The catalyst support Htlc was prepared using Cu and Al, the former being water gas shift (WGS) promoter. Furthermore, the effect of promotion by Pt was investigated with three different loadings (1–5%), where 2.5% Pt outperformed others. The Ni loading was fixed at 10% in all the catalysts. The synthesized catalyst was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis and Fourier transform infrared spectroscopy (FTIR). Finally, based on the experimental data, a rate law was proposed where the rate constant and adsorption constant of lactose were determined using multilinear regression. This work provides a proof-of-concept investigation for valorising CWE via APR using a novel catalyst Pt-Ni/Htlc.

The potential of Moringa Olivera biochar-modified Mg/Fe layered double hydroxides (LDHs) nanosheets as a sustainable adsorbent for removing naphthol green (NG) has been studied. Mg/Fe-LDH modified with Moringa biochar was created using in situ co-precipitation method. The synthetic LDHs were characterized using thermogravimetric analysis (TGA), field emission scan electron microscope (FE-SEM), transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDS), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) techniques for nitrogen adsorption–desorption. Experimental design techniques are employed to optimize removal efficiency by examining factors such as pH, temperature, adsorbent dosage, and contact time. The resulting LDHs exhibits improved adsorption properties due to the combined effects of Mg/Fe LDHs and the high surface area of Moringa biochar (S_BET increased from 87 to 144 m²/g after modification with biochar). Through response surface methodology, optimal conditions are determined to maximize NG removal and found to be pH 7.8, contact time 150 min, dose 380 mg, and temperature 25°C. With an R² value of 0.999, 0.998 and an adjusted R² value of 0.997 and 0.993 in the RSM model for Mg/Fe and Mg/Fe-BC LDH, respectively, it can be concluded that the chosen model is appropriate for data analysis (quadratic model). Additionally, the adequacy precision was assessed using the signal-to-noise ratio, which was determined to be around 23 and 66 for Mg/Fe and Mg/Fe-BC LDH, respectively (significantly higher than the baseline of 4), indicating a satisfactory signal. The highest adsorption capacity of Mg/Fe and Mg/Fe-BC LDHs was determined to be 43 and 53 mg.g⁻¹ (with removal efficiencies of 82 and 97%, respectively). The Freundlich adsorption isotherm model testing characterized the removal of NG. A comprehensive kinetic study reveals a pseudo-first order. This study finds out the potential of Moringa biochar-modified Mg/Fe LDHs nanosheets as an effective green adsorbent for naphthol green removal in comparison with Mg/Fe free of biochar.

Graphical Abstract

The recent advances in the green-based design and synthesis of core-shell nanostructures have always been an intriguing arena to scientists due to their compelling application in catalytic fields. This work designed and synthesized a new core-shell nanosphere based on Fe₃O₄ as a novel, heterogeneous, reusable, efficient, and green catalyst to synthesize benzothiazole derivatives under ultrasonic irradiation. To achieve this goal, initially, fabricated Fe₃O₄ magnetic nanoparticles via the co-operation method were synthesized as a core, followed by coating with polyethylene glycol (PEG-400). Subsequently, Ni@Murexide complex supported on magnetic nanoparticles is successfully synthesized and reported, modified using 3-chloropropyltriethoxysilane (CPTES) and Murexide (MX) ligand in the Fe₃O₄@PEG support. The obtained structure of Fe₃O₄@PEG/MX/Ni was characterized by different analyses such as FT-IR, SEM, EDS, TEM, ICP-OES, XRD, VSM, and TGA. The results illustrated the effect of ultrasonic irradiation and the high efficacy of Murexide as a ligand in catalyzing the formation of benzothiazole derivatives and confirming the findings from the reaction of different derivatives of aromatic aldehyde with electron-withdrawing/donor groups with 2-amino thiophenol through a one-pot process in 10 min under ultrasonic irradiation which shows the non-sensitivity of the process to electronic effects. Furthermore, Fe₃O₄@PEG/MX@Ni showed great use at least six times with no significant loss in catalyst activity.

Hydrodeoxygenation (HDO) is a promising way to produce the second generation biodiesel from aliphatic acid based biomass. In this study, Ni_xMo_y@NC bimetallic catalysts with varying molar ratios were prepared using ZIF-8 as a representative MOF precursor. Lauric acid was chosen as the model compound, the catalytic performance of these catalysts with different metal ratios, reaction temperatures, and pressures was investigated. In addition, the reaction of lauric acid, lauric alcohol, and lauric aldehyde at different reaction times were investigated to explore the pathways of lauric acid. The influence of Mo doping on the catalyst structure, reducibility, and electronic properties was investigated through a series of characterizations, including SEM, TEM, XPS, H₂-TPR, and NH₃-TPD. This study revealed that the ZIF-8 support with incorporated Ni and Mo maintained a stable structure. Compared to Ni-based catalysts, the addition of Mo in the bimetallic catalyst can bring the electron transfer between Ni and Mo and increased the active sites and acid sites. An appropriate amount of Mo can lower the reduction temperature and enhance the catalytic activity for hydrogenation and deoxygenation reactions. Based on the catalytic experimental results, it can be observed that liquid alkanes, such as undecane and dodecane, are primarily formed through decarbonylation of lauric aldehyde and hydrodeoxygenation of lauric alcohol. Additionally, under high-temperature conditions, the hydrodeoxygenation reaction is favored over the decarbonylation reaction, promoting the production of dodecane. This indicates that Mo exhibits better activation for the C–OH reaction, leading to these observations. Under repeated use, the catalyst still has good catalytic activity and stability.

Zeolites (Hβ, HZSM-5 and HM), TiO₂ and ZrO₂ supported NiCo alloy catalysts were tested for the hydrodeoxygenation of phenol in aqueous phase. It has been found that the catalyst acidity remarkably influences the catalyst activity and the product distribution. Zeolites supported catalysts give much higher yield of the deoxygenated products (mainly benzene and cyclohexane) than NiCo/TiO₂ and NiCo/ZrO₂, where cyclohexanol and cyclohexanone are dominating. Associated with NH₃-TPD, we suggest that the catalyst acidity promotes the hydrodeoxygenation. Hβ zeolite supported NiCo alloy is more active than others, attributed to its higher metal dispersion and more acid sites. Therein, the Hβ zeolite calcined at 750 ^oC has moderate acidity, and its supported NiCo alloy catalyst (NiCo/HB-750) shows the best performance. Under a suitable reaction condition, the phenol conversion and the total yield of deoxygenated products reaches 96.8% and 94.5% on NiCo/HB-750, respectively.

Abstract

Natural hematite supported cobalt (Co/Nat-Hem), a new heterogeneous catalyst, was successfully prepared by a simple impregnation technique. Textural, structural, functional groups and morphological aspects of the prepared catalyst were analyzed by BET, XRD, FT-IR, XRF, pH_pzc, SEM-EDX methods. BET analysis shows that the Co/Nat-Hem catalyst has a specific surface area of ​​13.44 m²/g and a pore volume of 0.062 cm³/g. The SEM-EDX method showed that 7.19 wt% of the cobalt species were dispersed on the surface of the prepared catalyst. The catalytic activity of Co/Nat-Hem was evaluated by photo-Fenton oxidation of the dye Cong red (CR). The effect of reaction parameters on CR oxidation efficiency was investigated. Under optimal reaction conditions (1 g/L catalyst concentration, 0.2 mol/L H₂O₂ initial concentration and pH 3), the percentage of CR discoloration reaches 97% after 30 min. The Co/Nat-Hem catalyst achieved a synergistic ratio of 28.5%, which was added to the oxidation rate of the Nat-Hem catalyst. The stability of the Co/Nat-Hem catalyst was demonstrated by the limited activity of leachates in the homogeneous Fenton oxidation of CR. The phytotoxicity of the CR dye was tested during the irrigation of the bean (Vicia faba L.).

In this research, the photocatalytic degradation of methylene blue was investigated using synthesized PdO/CoS nanocomposite under visible light irradiation. The structural and morphological properties were determined using X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, Mott–Schottky analysis, and transmission electron microscopy (TEM). The Mott–Schottky analysis confirmed the formation of a p-n heterojunction, and the flat band potential values for the n-type and p-type semiconductors were found to be − 1 and 1.3, respectively. The bandgap of the composite was determined to be 3 eV using Diffuse Reflectance Spectroscopy (DRS). When 0.1 g of the synthesized composite was used for 90 min, it successfully degraded 91% of methylene blue with an initial concentration of 10 ppm. In the Design of Experiments (DOE) approach, the optimum conditions for this research were found to be a catalyst mass of 0.06 g, an initial dye concentration of 8 ppm, and 2% palladium doping at pH 10, resulting in a 92.38% degradation efficiency in 110 min. To model the degradation of methylene blue using the synthesized composite, the Fritz–Schlunder and Koble–Corrigan models achieved the highest correlation coefficients (0.995 and 0.992, respectively) and the lowest error functions (0.024, 0.0008) and (0.032, 0.002), respectively. Additionally, the Langmuir–Hinshelwood and Intra-particle diffusion control kinetic models showed the highest correlation coefficient (98%). In summary, the study demonstrated that the PdO/CoS composite exhibited excellent photocatalytic activity for methylene blue degradation, and the optimized conditions resulted in high degradation efficiency. The proposed kinetic models provided valuable insights into the degradation mechanism of methylene blue using the synthesized composite.

In this work, MoVTeNbO_x catalysts was doped with Cr by using spray drying method. The effect of Cr doping on the crystalline phase, physicochemical properties, and catalytic performance of selective oxidation of propane to acrylic acid of MoVTeNbO_x was investigated. The results showed that the samples as-prepared by spray drying method present unique spherical morphology stacked by rod particles. In addition, Cr doping induced a change in the mesopore structure formed by rod stacking, reducing the pore radius of the catalysts from 5-10 nm to 2-4 nm. Meanwhile, Cr doping dramatically reduced the average particle size of MoVTeNbO_x catalysts, decreasing the rod cross-section diameter of catalysts from 234.21 to 134.96 nm and the rod length from 1.096 μm to 485.71 nm, which significantly increased the amount of (001) active crystalline plane. Moreover, an appropriate amount of Cr doping increased the number of reducible species in the catalyst and reduced its acidity. At the same time, the surface V⁵⁺ content of the catalyst was increased from 35.8% to 72.6%. Cr-doped MoVTeNbO_x with mesoporous structure showed excellent performance in catalyzing selective oxidation of propane to acrylic acid reaction. Among them, S-3 sample (V: Cr = 1:0.015) increased the selectivity and yield to acrylic acid from 67.5% to 84.3% and from 26.4% to 43.2%, respectively, at reaction temperature of 380 °C.