Article
Chemistry, Physical
Mariana N. Catrinck, Sebastiano Campisi, Paolo Carniti, Reinaldo F. Teofilo, Filippo Bossola, Antonella Gervasini
Summary: In this study, physical mixtures of Nb2O5•nH(2)O and NbOPO4 were prepared to investigate the role of phosphate groups in total acidity and two reactions involving carbohydrate biomass. The acid and catalytic properties were influenced by phosphate group enrichment. The presence of Bronsted sites on the surface favored inulin conversion and NbOPO4 exhibited the best hydrolysis activity with glucose/fructose formation. Additionally, a catalyst with a more phosphated surface showed reduced deactivation during the dehydration of fructose/glucose into HMF.
Article
Chemistry, Applied
Yayati Naresh Palai, Abhijit Shrotri, Miyuki Asakawa, Atsushi Fukuoka
Summary: A highly efficient Lewis acid catalyst for the isomerization of glucose to fructose was synthesized by controlling the dispersion of Sn on SBA15. The catalyst exhibited high selectivity and fructose yield, while mechanisms involving condensation of Sn with silanol groups on SBA15 were proposed. Despite deactivation due to byproduct deposition in the third cycle, catalyst activity could be restored by calcination.
Article
Energy & Fuels
Saeed Sahebdelfar, Parisa Moghimpour Bijani, Fereydoon Yaripour
Summary: The kinetics of deactivation of gamma-alumina catalyst in the dehydration of methanol to dimethyl ether were investigated, revealing a second-order independent deactivation kinetics that accurately fit the experimental data. The activation energies for the main reaction and catalyst deactivation were obtained, with the latter showing a negative value due to reversible partial hydration. At higher temperatures, irreversible sintering of alumina crystallites became the predominant deactivation mechanism.
Article
Chemistry, Multidisciplinary
Hongtao Zhang, Xiao Liu, Miaomiao Han, Rui Zhang
Summary: In this study, a three-component deep eutectic solvent system was used to convert bio-carbohydrates into 5-hydroxymethylfurfural (HMF). The method showed high conversion and yield, as well as better selectivity, making it a promising alternative for the utilization of biomass.
Article
Chemistry, Multidisciplinary
Dong-Chang Kang, Seung Hee Pyen, Eun-Jeong Kim, Young Woo Kim, Young-Woong Suh, Dong-Pyo Kim, Chae-Ho Shin, Hyung-Ki Min
Summary: The study investigated the dehydration of formic acid over supported phosphotungstic acid (HPW) catalysts for the production of hydrogen-free carbon monoxide (CO). The acidity of the catalysts was influenced by the type of support (SiO2, Al2O3, ZrO2, and TiO2) and HPW content (0.0-20.0 wt.%), as shown by IPA-TPD and Py-IR. The catalytic activity exhibited a volcano-type distribution with the HPW content, reaching a maximum at 15 wt.%. The catalytic activity was more closely related to the density of Bronsted acids and inversely proportional to the propylene desorption peak temperature during IPA-TPD. The presence of strongly adsorbed H2O during formic acid dehydration led to catalyst deactivation, especially at lower reaction temperatures (<230 degrees C).
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2023)
Article
Engineering, Environmental
Yu-Kun Ma, Li -Li Xu, Long-Ren Ouyang, Lu-Lu Huang, Ai -Ping Jia, Yu Wang, Ji-Qing Lu
Summary: The Pt/ZSM-5-18 catalyst with a Si/Al molar ratio of 18 in the support is highly active for the oxidation of CH2Cl2, showing high selectivity towards CO2 formation. The excellent performance is attributed to abundant surface acidity and strong oxidation ability. The rate-limiting step is the C-Cl cleavage of CH2Cl2, while the oxidation of CH3Cl and CO is more facile. The catalyst's stability is hardly affected by Pt aggregation.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Ramakrishna Chava, Anil Kumar Seriyala, D. Bhaskar Anurag Varma, Karthiek Yeluvu, Banasri Roy, Srinivas Appari
Summary: The A-site deficient La0.9_xBaxAl0.85Ni0.15O3 (x = 0, 0.02, 0.04, and 0.06) perovskite oxide catalyst was developed and used for dry reforming of model biogas. The catalysts were prepared using a citrate sol-gel method and analyzed using various techniques. The partial doping of Ba improved the catalytic activity and stability, resulting in the highest performance observed for La0.84Ba0.06Al0.85Ni0.15O3 (LB6AN-15).
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Multidisciplinary
Di Xu, Haifeng Fan, Kaidi Liu, Guoqiang Hou, Chuan Qin, Yanfei Xu, Rui Li, Junhu Wang, Mingyue Ding
Summary: The deactivation mechanism of a typical Fe-based/zeolite bifunctional catalyst in CO2 hydrogenation is investigated in this study. The structure-activity relationship of the KFe/ZSM-5 bifunctional catalyst is studied, and it is found that the migration of K and the Fe-zeolite interaction are the main reasons for catalyst deactivation. These factors result in electron deficiency on the Fe surface, inhibiting the activation of CO2 and the formation of active sites. Additionally, the migration of K poisons the acidic sites of the zeolite component, affecting product selectivity.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Energy & Fuels
Katarzyna Morawa Eblagon, Ana Arenillas, Anna Malaika, M. Fernando R. Pereira, Jose Luis Figueriredo
Summary: The study focuses on the surface chemistry of phosphorus-doped carbon xerogels (CX_P) to enhance their catalytic performance in the eco-friendly production of 5-hydroxymethylfurfural (HMF). By controlling the active sites and modifying the reaction atmosphere, an excellent HMF yield of 73.3% was obtained in just 2 hours using CX_P thermally treated in air in the H2O-CO2 reaction system. The presence of oxygen functionalities and phosphates in the catalyst played a crucial role in improving the selectivity towards HMF.
Article
Chemistry, Applied
Xuehao Li, Qichen Wang, Chuanmin Ding, Yuanyuan Meng, Junwen Wang, Kan Zhang, Ping Liu
Summary: Nitrogen-doped, boron-doped, and boron and nitrogen co-doped activated carbon supported nickel-copper catalyst was used for ethanol gas-phase carbonylation reaction, leading to greatly improved yields of propionic acid and ethyl propionate. The effects of nitrogen and boron doping on catalytic performance were investigated using BET, XRD, XPS, TEM, and CO-TPD. Nitrogen and boron doping improved the dispersion of metal on the surface of activated carbon. The catalyst regeneration method was explored to address the low stability of nickel-based catalyst, and it was found that H-2 treatment at 400 degrees Celsius could restore the catalyst activity. Based on the catalyst regeneration experiment and characterization of the catalyst before and after the reaction and regeneration, the deactivation of the catalyst was attributed to the formation of NiI2.
JOURNAL OF POROUS MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yao Shen, Fang Lin, Kang Wang, Xitao Wang
Summary: By doping CaO, alkyl grafting and NbCl5 impregnation on γ-Al2O3 beads, an efficient catalyst was constructed for the conversion of glucose to 5-HMF. Under suitable reaction conditions, complete conversion of glucose and high yield of 5-HMF can be achieved.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Israel Pala-Rosas, Jose L. Contreras, Jose Salmones, Beatriz Zeifert, Ricardo Lopez-Medina, Juan Navarrete-Bolanos, Sofia Hernandez-Ramirez, Jennipher Perez-Cabrera, Andres A. Fragoso-Montes de Oca
Summary: The study found that increasing the SiO2/Al2O3 molar ratio of HY zeolites decreases the total amount of acid sites per unit area, leading to a reduced initial glycerol conversion; however, the initial acrolein selectivity increases with the higher Brønsted/Lewis acid sites ratio. The catalyst lifetime depends on pore structure, with larger surface areas improving deactivation rate constants.
Article
Chemistry, Applied
Nikolaos Nikolopoulos, Luke A. Parker, Maurits W. Vuijk, Bert M. Weckhuysen
Summary: One of the main challenges for the chemical industries is finding new ways to produce lower olefins, such as propylene and ethylene, to satisfy the increase in demand for polymers. The addition of magnesium to zeolites in the MTH process has been studied to enhance the selectivity towards light olefins. Adjusting the location of magnesium in zeolite-based catalyst bodies has shown to have a significant impact on their physicochemical properties and catalytic performance in the MTH reaction.
MICROPOROUS AND MESOPOROUS MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Preeti Sahu, Adarsh Sahu, Ayyamperumal Sakthivel
Summary: This study presents the preparation of gallium-containing MCM-22 zeolite material and its application in the synthesis of 2,3-dihydroquinazolin-4(1H)-ones. The material showed excellent isolated yield in the reaction, with strong acidic sites and a microporous nature.
Article
Energy & Fuels
Phan Huy Hoang, Thai Dinh Cuong
Summary: A feasible catalytic process was developed for the simultaneous direct production of 5-hydroxymethylfurfural (HMF) and furfural from corncob biomass. By optimizing the conditions, the yields of HMF and furfural were significantly improved while the formation of levulinic acid was reduced.
Article
Chemistry, Applied
Qingyuan Zheng, Jack H. Williams, Scott Elgersma, Mick D. Mantle, Andrew J. Sederman, G. Leendert Bezemer, Constant M. Guedon, Lynn F. Gladden
Summary: In this study, a pilot-scale fixed-bed reactor compatible with NMR/MRI was developed for Fischer-Tropsch synthesis. Multiple magnetic resonance techniques were applied to quantitatively characterize different product species within catalyst pellets, providing valuable information for catalyst and reactor optimization.
Article
Chemistry, Applied
Lisa Ramisch, Sebastian Pfaff, Sabrina M. Gericke, Edvin Lundgren, Johan Zetterberg
Summary: We present a combination of optical operando techniques that allow simultaneous measurement of adsorbed species on catalyst surfaces, monitoring of surface oxide formation, and imaging of the gas phase above the catalyst surface. The experimental setup was validated by studying CO oxidation on Pd(100) at different pressures, revealing the effects of pressure on the heterogeneous catalytic reaction.
Article
Chemistry, Applied
Marta Paniagua, Gabriel Morales, Juan A. Melero, Daniel Garcia-Salgado
Summary: The influence of common impurities in levulinic acid on the catalytic performance of different acid catalysts for bio-jet fuel production was studied. It was found that furfural had the greatest detrimental effect on catalyst performance, while propyl-sulfonic acid-modified SBA-15 and sulfonic acid resin Amberlyst-70 showed good regeneration ability.
Article
Chemistry, Applied
Jesus Tapiador, Pedro Leo, Guillermo Calleja, Gisela Orcajo
Summary: This study presents a new MOF material, Zn-URJC-13, with acid and basic sites, permanent porosity, and high affinity to CO2 molecules. The Zn-URJC-13 catalyst exhibits efficient performance in CO2 cycloaddition reactions and can be reused multiple times.
Article
Chemistry, Applied
Dan Zhao, Vita A. Kondratenko, Dmitry E. Doronkin, Shanlei Han, Jan-Dierk Grunwaldt, Uwe Rodemerck, David Linke, Evgenii V. Kondratenko
Summary: This study demonstrates the potential of cheap and commercially available Zr or Ti-based supports and ZnO to serve as active and selective catalysts for propane dehydrogenation (PDH). The catalytically active species formed in situ under PDH conditions consist of isolated ZnOx. ZnOx on the surface of LaZrOx shows the highest rate of propene formation.
Article
Chemistry, Applied
Hanbyeol Kim, Jung Rae Kim, Young-Kwon Park, Jeong-Myeong Ha, Jungho Jae
Summary: In this study, metal phosphates were used as catalysts for biomass conversion to produce sustainable aromatics through DielsAlder cycloaddition reactions. The effects of synthesis method, activation method, and P/Ti molar ratio on the structure and acid properties of titanium phosphate catalysts were systematically studied. The mesoporous titanium phosphate catalyst synthesized by hydrothermal method at 180℃ for 12 h followed by ethanol refluxing at 60℃ for 24 h at a molar P/Ti ratio of 1 showed the highest surface area and acid site density.
Article
Chemistry, Applied
Yasin Khani, Sumin Pyo, Kwang-Eun Jeong, Chul-Ung Kim, Moonis Ali Khan, Byong-Hun Jeon, Kun-Yi Andrew Lin, Siyoung Q. Choi, Young-Kwon Park
Summary: A protonated form of Zeolite Socony Mobil-5 (H-ZSM-5) catalyst was synthesized through a hydrothermal method using different sources of silica. The effect of loading the catalyst with yttrium, samarium, and gadolinium on the acidic properties was investigated. Among the metal-loaded catalysts, the Sm/LHZ catalyst showed the best performance in the methanol to propylene conversion due to its high amount of weak and intermediate acid sites, while the Gd-LHZ catalyst increased the selectivity towards ethane and propane.
Article
Chemistry, Applied
Michael Franc, Ivana Cisarova, Jan Vesely
Summary: The present study investigates an enantioselective cyclization of enals with imidazolone derivatives catalyzed by a combination of achiral Pd(0) complex and chiral secondary amine. Corresponding spirocyclic imidazolones were produced in high yields with moderate diastereoselectivity and excellent enantioselectivity. The developed co-operative catalytic methodology provides a highly substituted spirocyclic scaffold with four stereogenic centers under mild conditions.
Article
Chemistry, Applied
Mauro Alvarez, Jennifer Cueto, David P. Serrano, Pablo Marin, Salvador Ordonez
Summary: This study focuses on improving the formulation and preparation methods of catalysts for the production of dimethyl carbonate. By using suitable catalyst preparation methods and copper salt precursors, the researchers successfully produced catalysts with optimal performance for dimethyl carbonate formation.
Article
Chemistry, Applied
Claudia J. Keijzer, Luc C. J. Smulders, Dennie Wezendonk, Jan Willem de Rijk, Petra E. de Jongh
Summary: This study investigates the catalytic behavior of alpha-alumina supported silver catalysts in the presence of chloride. It is found that the particle size of silver can affect the selectivity of the catalyst, but different strategies lead to different results. In this size range, the selectivity of ethylene oxide is correlated to the Ag : Al2O3 surface ratio.
Article
Chemistry, Applied
Takeshi Aihara, Wataru Aoki, Michikazu Hara, Keigo Kamata
Summary: The development of acid-base bifunctional catalysts is important for promoting specific chemical transformations. In this study, Ti-based perovskite oxides were synthesized and used as catalysts for two C-C bond-forming reactions (cyanosilylation and Knoevenagel condensation). The highly pure SrTiO3 nanoparticles with a high specific surface area exhibited the highest catalytic performance, and could be easily recovered and reused.
Article
Chemistry, Applied
Olga Gorlova, Petra Pribylova, Eliska Vyskocilova, Katerina Peroutkova, Jan Kohout, Iva Paterova
Summary: This study investigates the Baeyer-Villiger oxidation of beta-cyclocitral using tin-modified mixed oxides as catalysts. The optimal reaction conditions and the effects of various factors on the reaction course and selectivity were determined. The results show that tin-modified mixed oxides exhibit high activity and selectivity in the oxidation reaction.
Article
Chemistry, Applied
M. I. Avila, M. M. Alonso-Doncel, L. Briones, G. Gomez-Pozuelo, J. M. Escola, D. P. Serrano, A. Peral, J. A. Botas
Summary: The catalytic fast pyrolysis of lignin using ion-exchanged zeolite catalysts showed significant improvements in bio-oil quality and the production of aromatic hydrocarbons and oxygenated compounds.
Article
Chemistry, Applied
Enrico Catizzone, Giorgia Ferrarelli, Paolo Bruno, Girolamo Giordano, Massimo Migliori
Summary: The acid-catalysed alcohol conversion reaction is a promising route for de-fossilization strategies. Research on pure alcohol conversion and simultaneous dehydration of mixed alcohols have shown different product compositions, with the type and distribution of acid sites affecting the reaction mechanism.
Article
Chemistry, Applied
Alireza Ranjbari, Juho Kim, Jihee Yu, Jiyun Kim, Mireu Park, Nayoung Kim, Kristof Demeestere, Philippe M. Heynderickx
Summary: This study investigated a novel kinetic model for the adsorption and photocatalytic degradation of methyl orange using commercial ZnO and reduced ZnO photocatalysts. The results provided new insights into the interaction of catalysts with molecules of different charges and compared with a previous study on methylene blue. The presence of oxygen vacancies in ZnO and their effects on adsorption and photocatalytic degradation were analyzed, and the photocatalytic degradation rate of reduced ZnO was found to increase significantly.