Molecules

Research

18 pages, 2415 KiB

Open AccessArticle

Effect of Residual Cuts on Deactivation of Hierarchical Y Zeolite-Based Catalysts during Co-Processing of Vacuum Gas Oil (VGO) with Atmospheric Residue (ATR)

by Jayson Fals, Esneyder Puello-Polo and Edgar Márquez

Molecules 2024, 29(19), 4753; https://doi.org/10.3390/molecules29194753 - 8 Oct 2024

Viewed by 507

Abstract

The influence of residual cuts on the deactivation of hierarchical Y zeolite-based catalysts during the co-processing of vacuum gas oil (VGO) with atmospheric residue (ATR) was investigated. The experiments were conducted in a laboratory-scale MAT-type reactor. The conversion of VGO, ATR, and their [...] Read more.

The influence of residual cuts on the deactivation of hierarchical Y zeolite-based catalysts during the co-processing of vacuum gas oil (VGO) with atmospheric residue (ATR) was investigated. The experiments were conducted in a laboratory-scale MAT-type reactor. The conversion of VGO, ATR, and their 70:30 (mass basis) mixture was examined using two composite catalysts: Cat.Y.0.00 and Cat.Y.0.20. The operating conditions closely resembled those of the commercial catalytic cracking process (550 °C and contact times of 10 to 50 s). When ATR was processed individually, the conversion remained below 50 wt%. However, significant improvements in conversion rates were achieved and catalyst deactivation was mitigated when ATR was co-processed with VGO. Notably, the BET surface area and average mesopore volume were adversely impacted by ATR, which also led to the accumulation of high levels of metals and nitrogen on the spent catalyst, detrimentally affecting its acidic and structural properties. Moreover, substantial coke deposition occurred during ATR cracking. The soluble and insoluble coke analysis revealed H/C ratio values of up to 0.36, indicative of polycondensed coke structures with more than ten aromatic rings. The nature of the coke was confirmed through TPO and FTIR analyses. Interestingly, the CatY.0.20 catalyst exhibited less activity loss, retaining superior acid and structural properties. Co-processing Colombian atmospheric residue with ATR loadings of 30 wt% (higher than the typical 20 wt%) in catalysts formulated with hierarchical zeolites presents a promising alternative for commercial applications. This research opens avenues for optimizing catalytic cracking processes. Full article

(This article belongs to the Special Issue Catalysts: New Materials for Green Chemistry)

► Show Figures

Figure 1

16 pages, 2117 KiB

Open AccessArticle

Analysis of the Behavior of Deep Eutectic Solvents upon Addition of Water: Its Effects over a Catalytic Reaction

by Paola R. Campodónico, Jazmín Alarcón-Espósito, Jackson J. Alcázar, Belén Olivares and Cristian Suárez-Rozas

Molecules 2024, 29(14), 3296; https://doi.org/10.3390/molecules29143296 - 12 Jul 2024

Viewed by 1090

Abstract

This study presents the potential role of deep eutectic solvents (DESs) in a lipase-catalyzed hydrolysis reaction as a co-solvent in an aqueous solution given by a phosphate buffer. Ammonium salts, such as choline chloride, were paired with hydrogen bond donors, such as urea, [...] Read more.

This study presents the potential role of deep eutectic solvents (DESs) in a lipase-catalyzed hydrolysis reaction as a co-solvent in an aqueous solution given by a phosphate buffer. Ammonium salts, such as choline chloride, were paired with hydrogen bond donors, such as urea, 1,2,3-propanetriol, and 1,2 propanediol. The hydrolysis of p-nitrophenyl laureate was carried out with the lipase Candida antarctica Lipase B (CALB) as a reaction model to evaluate the solvent effect and tested in different DES/buffer phosphate mixtures at different

% w / w

. The results showed that two mixtures of different DES at 25

% w / w

were the most promising solvents, as this percentage enhanced the activities of CALB, as evidenced by its higher catalytic efficiency (

\frac{k_{c a t}}{K_{M}}

). The solvent analysis shows that the enzymatic reaction requires a reaction media rich in water molecules to enable hydrogen-bond formation from the reaction media toward the enzymatic reaction, suggesting a better interaction between the substrate and the enzyme-active site. This interaction could be attributed to high degrees of freedom influencing the enzyme conformation given by the reaction media, suggesting that CALB acquires a more restrictive structure in the presence of DES or the stabilized network given by the hydrogen bond from water molecules in the mixture improves the enzymatic activity, conferring conformational stability by solvent effects. This study offers a promising approach for applications and further perspectives on genuinely green industrial solvents. Full article

(This article belongs to the Special Issue Catalysts: New Materials for Green Chemistry)

► Show Figures

Figure 1

11 pages, 1112 KiB

Open AccessArticle

Mild Iron-Catalyzed Oxidative Cross-Coupling of Quinoxalinones with Indoles

by Hangcheng Ni, Hui Mao, Ying Huang, Yi Lu and Zhenxiang Liu

Molecules 2024, 29(11), 2649; https://doi.org/10.3390/molecules29112649 - 4 Jun 2024

Viewed by 548

Abstract

Utilizing iron chloride as a Lewis acid catalyst, we developed a straightforward and mild oxidative cross-coupling reaction between quinoxalinones and indoles, yielding a series of versatile 3-(indol-3-yl)quinoxalin-2-one derivatives. This approach allows for the incorporation of a wide array of functional groups into the [...] Read more.

Utilizing iron chloride as a Lewis acid catalyst, we developed a straightforward and mild oxidative cross-coupling reaction between quinoxalinones and indoles, yielding a series of versatile 3-(indol-3-yl)quinoxalin-2-one derivatives. This approach allows for the incorporation of a wide array of functional groups into the final products, demonstrating its synthetic versatility. Notably, the method was successfully scaled up to gram-scale reactions while maintaining high yields. Our mechanistic investigation indicates that iron chloride serves as a catalyst to facilitate the formation of key intermediates which subsequently undergo oxidation to afford the desired products. The merits of this protocol include its cost effectiveness, operational simplicity, and the ease of product isolation via filtration. Full article

(This article belongs to the Special Issue Catalysts: New Materials for Green Chemistry)

► Show Figures

Graphical abstract

16 pages, 4927 KiB

Open AccessArticle

Optimization of Biodiesel Production Process Using MoO₃ Catalysts and Residual Oil: A Comprehensive Experimental 2³ Study

by Adriano Lima da Silva, Helder de Lucena Pereira, Herbet Bezerra Sales, Juliana Kelly Dionízio, Mary Cristina Ferreira Alves, Danyelle Garcia Guedes, Carlos Bruno Barreto Luna and Ana Cristina Figueiredo de Melo Costa

Molecules 2024, 29(10), 2404; https://doi.org/10.3390/molecules29102404 - 20 May 2024

Cited by 2 | Viewed by 972

Abstract

The study aimed to utilize MoO₃ catalysts, produced on a pilot scale via combustion reaction, to produce biodiesel from residual oil. Optimization of the process was conducted using a 2³ experimental design. Structural characterization of the catalysts was performed through X-ray [...] Read more.

The study aimed to utilize MoO₃ catalysts, produced on a pilot scale via combustion reaction, to produce biodiesel from residual oil. Optimization of the process was conducted using a 2³ experimental design. Structural characterization of the catalysts was performed through X-ray diffraction, fluorescence, Raman spectroscopy, and particle size distribution analyses. At the same time, thermal properties were examined via thermogravimetry and differential thermal analysis. Catalytic performance was assessed following process optimization. α-MoO₃ exhibited a monophasic structure with orthorhombic phase, whereas α/h-MoO₃ showed a biphasic structure. α-MoO₃ had a larger crystallite size and higher crystallinity, with thermal stability observed up to certain temperatures. X-ray fluorescence confirmed molybdenum oxide predominance in the catalysts, with traces of iron oxide. Particle size distribution analyses revealed polymodal distributions attributed to structural differences. Both catalysts demonstrated activity under all conditions tested, with ester conversions ranging from 93% to 99%. The single-phase catalyst had a long life cycle and was reusable for six biodiesel production cycles. The experimental design proved to be predictive and significant, with the type of catalyst being the most influential variable. Optimal conditions included α-MoO₃ catalyst, oil/alcohol ratio of 1/15, and a reaction time of 60 min, resulting in high biodiesel conversion rates and showcasing the viability of MoO₃ catalysts in residual oil biodiesel production. Full article

(This article belongs to the Special Issue Catalysts: New Materials for Green Chemistry)

► Show Figures

Graphical abstract

17 pages, 5267 KiB

Open AccessArticle

Enhanced and Sustainable Removal of Indoor Formaldehyde by Naturally Porous Bamboo Activated Carbon Supported with MnO_x: Synergistic Effect of Adsorption and Oxidation

by Zhenrui Li, Yujun Li, Shijie Li, Jianfeng Ma, Qianli Ma, Zhihui Wang, Jiajun Wang, Keying Long and Xing’e Liu

Molecules 2024, 29(3), 663; https://doi.org/10.3390/molecules29030663 - 31 Jan 2024

Cited by 1 | Viewed by 1238

Abstract

Novel bamboo activated carbon (BAC) catalysts decorated with manganese oxides (MnO_x) were prepared with varying MnO_x contents through a facile one-step redox reaction. Due to the physical anchoring effect of the natural macropore structure for catalyst active components, homogeneous MnO [...] Read more.

Novel bamboo activated carbon (BAC) catalysts decorated with manganese oxides (MnO_x) were prepared with varying MnO_x contents through a facile one-step redox reaction. Due to the physical anchoring effect of the natural macropore structure for catalyst active components, homogeneous MnO_x nanoparticles (NPs), and high specific surface area over catalyst surface, the BAC@MnO_x-N (N = 1, 2, 3, 4, 5) catalyst shows encouraging adsorption and catalytic oxidation for indoor formaldehyde (HCHO) removal at room temperature. Dynamic adsorption and catalytic activity experiments were conducted. The higher S_micro (733 m²/g) and V_micro/V_t (82.6%) of the BAC@MnO_x-4 catalyst could facilitate its excellent saturated and breakthrough adsorption capacity (5.24 ± 0.42 mg/g, 2.43 ± 0.22 mg/g). The best performer against 2 ppm HCHO is BAC@MnO_x-4 catalyst, exhibiting a maximum HCHO removal efficiency of 97% for 17 h without any deactivation as RH = 0, which is higher than those of other MnO_x-based catalysts. The average oxidation state and in situ DRIFTS analysis reveal that abundant oxygen vacancies on the BAC@MnO_x-4 catalyst could be identified as surface-active sites of decomposing HCHO into the intermediate species (dioxymethylene and formate). This study provides a potential approach to deposit MnO_x nanoparticles onto the BAC surface, and this hybrid BAC@MnO_x material is promising for indoor HCHO removal at room temperature. Full article

(This article belongs to the Special Issue Catalysts: New Materials for Green Chemistry)

► Show Figures

Graphical abstract

16 pages, 8009 KiB

Open AccessArticle

Co-Immobilization of Laccase and Mediator into Fe-Doped ZIF-8 Significantly Enhances the Degradation of Organic Pollutants

by Zixuan Li, Qinghong Shi, Xiaoyan Dong and Yan Sun

Molecules 2024, 29(2), 307; https://doi.org/10.3390/molecules29020307 - 7 Jan 2024

Cited by 3 | Viewed by 1619

Abstract

Co-immobilization of laccase and mediator 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) for wastewater treatment could simultaneously achieve the reusability of laccase and avoid secondary pollution caused by the toxic ABTS. Herein, Fe-induced mineralization was proposed to co-immobilize laccase and ABTS into a metal–organic framework (ZIF-8) within [...] Read more.

Co-immobilization of laccase and mediator 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) for wastewater treatment could simultaneously achieve the reusability of laccase and avoid secondary pollution caused by the toxic ABTS. Herein, Fe-induced mineralization was proposed to co-immobilize laccase and ABTS into a metal–organic framework (ZIF-8) within 30 min. Immobilized laccase (Lac@ZIF-8-Fe) prepared at a 1:1 mass ratio of Fe²⁺ to Zn²⁺ exhibited enhanced catalytic efficiency (2.6 times), thermal stability, acid tolerance, and reusability compared to free laccase. ABTS was then co-immobilized to form Lac+ABTS@ZIF-8-Fe (ABTS = 261.7 mg/g). Lac@ZIF-8-Fe exhibited significantly enhanced bisphenol A (BPA) removal performance over free laccase due to the local substrate enrichment effect and improved enzyme stability. Moreover, the Lac+ABTS@ZIF-8-Fe exhibited higher BPA removal efficiency than the free laccase+ABTS system, implying the presence of a proximity effect in Lac+ABTS@ZIF-8-Fe. In the successive malachite green (MG) removal, the MG degradation efficiency by Lac@ZIF-8-Fe was maintained at 96.6% at the fifth reuse with only an extra addition of 0.09 mM ABTS in each cycle. As for Lac+ABTS@ZIF-8-Fe, 58.5% of MG was degraded at the fifth cycle without an extra addition of ABTS. Taken together, this research has provided a novel strategy for the design of a co-immobilized laccase and ABTS system for the degradation of organic pollutants. Full article

(This article belongs to the Special Issue Catalysts: New Materials for Green Chemistry)

► Show Figures

Graphical abstract

13 pages, 5183 KiB

Open AccessArticle

Enhanced Ammonia Decomposition by Tuning the Support Properties of Ni/Gd_xCe_1-xO_2-δ at 600 °C

by Haihua He, Chonglai Chen, Chaoqun Bian, Junhua Ren, Jiajia Liu and Wei Huang

Molecules 2023, 28(6), 2750; https://doi.org/10.3390/molecules28062750 - 18 Mar 2023

Cited by 4 | Viewed by 3007

Abstract

Ammonia decomposition is a promising method to produce high-purity hydrogen. However, this process typically requires precious metals (such as Ru, Pt, etc.) as catalysts to ensure high efficiency at relatively low temperatures. In this study, we propose using several Ni/Gd_xCe_1-x [...] Read more.

Ammonia decomposition is a promising method to produce high-purity hydrogen. However, this process typically requires precious metals (such as Ru, Pt, etc.) as catalysts to ensure high efficiency at relatively low temperatures. In this study, we propose using several Ni/Gd_xCe_1-xO_2-δ catalysts to improve ammonia decomposition performance by adjusting the support properties. We also investigate the underlying mechanism for this enhanced performance. Our results show that Ni/Ce_0.8Gd_0.2O_2-δ at 600 °C can achieve nearly complete ammonia decomposition, resulting in a hydrogen production rate of 2008.9 mmol.g⁻¹.h⁻¹ with minimal decrease over 150 h. Density functional theory calculations reveal that the recombinative desorption of nitrogen is the rate-limiting step of ammonia decomposition over Ni. Our characterizations indicate that Ni/Ce_0.8Gd_0.2O_2-δ exhibits a high concentration of oxygen vacancies, highly dispersed Ni on the surface, and abundant strong basic sites. These properties significantly enhance the associative desorption of N and strengthen the metal support interactions, resulting in high catalytic activity and stability. We anticipate that the mechanism could be applied to designing additional catalysts with high ammonia decomposition performance at relatively low temperatures. Full article

(This article belongs to the Special Issue Catalysts: New Materials for Green Chemistry)

► Show Figures

Figure 1

13 pages, 3340 KiB

Open AccessArticle

Enhanced Activity of Alkali-Treated ZSM-5 Zeolite-Supported Pt-Co Catalyst for Selective Hydrogenation of Cinnamaldehyde

by Shibo Cheng, Shan Lu, Xiang Liu, Gao Li and Fei Wang

Molecules 2023, 28(4), 1730; https://doi.org/10.3390/molecules28041730 - 11 Feb 2023

Cited by 4 | Viewed by 1998

Abstract

A bimetallic Pt8Co1 supported on alkali-treated ZSM-5 zeolite (ZSM-5-AT) was prepared through the impregnation method. The structure and surface properties of the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂-sorption and X-ray photoelectron spectroscopy (XPS) as well [...] Read more.

A bimetallic Pt8Co1 supported on alkali-treated ZSM-5 zeolite (ZSM-5-AT) was prepared through the impregnation method. The structure and surface properties of the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂-sorption and X-ray photoelectron spectroscopy (XPS) as well as temperature-programmed desorption of NH₃ (NH₃-TPD) and temperature-programmed reduction of H₂ (H₂-TPR). The TEM images present that the bimetallic Pt8Co1 nanoparticles with a mean particle size of 4–6 nm were uniformly dispersed on the alkali-treated ZSM-5 zeolite. The bimetallic Pt8Co1/ZSM-5-AT catalyst exhibited an extraordinary COL selectivity of 65% at a >99% CAL conversion efficiency, which showed a much higher catalytic performance (including the activity and selectivity) than the monometallic Pt/ZSM-5-AT and Co/ZSM-5-AT catalysts in the selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL) using hydrogen as reducing agent. The high catalytic activity of the bimetallic catalyst was attributed to the higher electron density of Pt species and more acidic sites of the alkali-treated ZSM-5 zeolite support. The recovery test showed no obvious loss of its initial activity of the Pt8Co1/ZSM-5-AT catalyst for five times. Full article

(This article belongs to the Special Issue Catalysts: New Materials for Green Chemistry)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Catalysts: New Materials for Green Chemistry

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (8 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI