Article
Chemistry, Multidisciplinary
Vahid Shadravan, Ang Cao, Vanessa J. Bukas, Mette K. Gronborg, Christian D. Damsgaard, Zhenbin Wang, Jakob Kibsgaard, Jens K. Norskov, Ib Chorkendorff
Summary: This study presents a new class of ruthenium-based catalysts promoted with metallic cesium using an in situ preparation technique. The in situ promoted catalysts show significantly higher activity, smaller apparent activation energy, and less susceptibility to H-2 poisoning compared to the ones prepared by traditional ex situ promotion methods. The findings suggest that this new technique can lead to a more sustainable and decentralized ammonia synthesis process.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Article
Chemistry, Physical
Kevin H. R. Rouwenhorst, Hugo G. B. Burbach, Dave W. Vogel, Judit Nunez Pauli, Bert Geerdink, Leon Lefferts
Summary: Recent research has shown that at temperatures above 300 degrees C, Ru catalysts exhibit significant thermal activity for NH3 synthesis, while at temperatures below 300 degrees C, plasma-catalytic ammonia synthesis is mainly attributed to adsorption of N radicals.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Physical
Wei Jiang, Jing-Pei Cao, Chen Zhu, Ming Zhao, Zhong-Hai Ni, Xiao-Yan Zhao, Jin-Xuan Xie, Liang Zhao, Yun-Peng Zhao, Hong-Cun Bai
Summary: This study investigates Ru-based catalysts for the selective hydrogenation of lignin-derived aromatic compounds and finds that Ru/alpha-Al2O3 catalyst exhibits excellent recyclability, air stability, and the highest activity. The mechanism of selective hydrogenation is revealed by experimental and theoretical calculations.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Multidisciplinary
Ruizhi Lai, Shuran Xu, Qingyao Zhang, Hui Zhou, Cankun Luo, Yuerong Wang, Li Hai, Yong Wu
Summary: A method for the synthesis of benzothiadiazine-1,1-dioxide and spiro benzothiadiazine derivatives through transition metal-catalyzed C-H activation/annulation was reported. The reaction substrates used were 3-phenyl-2H-benzothiadiazine-1,1-dioxide, and the coupling reagents used were vinylene carbonate and 4-diazopyrazolone. This strategy provides a straightforward and highly efficient approach to complex N-heterocycles.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Thorben Lenk, Valentin Ruess, Janko Gresch, Uwe Schroeder
Summary: This research investigates the use of various Pd- and Pt-containing electrocatalyst materials for electrochemical ring hydrogenation of aromatic compounds. The focus is on selectivity of the reaction based on the composition of the electrocatalyst, as well as understanding the electrocatalytic activity during repetitive electrode use. Different furanic derivatives are used as starting materials for mechanistic considerations. The study finds that furfural, furfuryl alcohol, and furan show high reactivity in ring hydrogenation reactions, while furoic acid and 2-methyl furan do not exhibit this behavior. Selectivities of up to 15.3% (from furfural) and 33% (from furfuryl alcohol) for tetrahydrofurfuryl alcohol are observed.
Article
Chemistry, Multidisciplinary
Christopher S. Gravatt, Luis Melecio-Zambrano, Tehshik P. Yoon
Summary: The sole method available for the photocycloaddition of unconjugated aliphatic alkenes is the Cu-catalyzed Salomon-Kochi reaction. A new catalyst system with superior reactivity and photostability has been designed, offering significantly expanded substrate scope and highlighted through the preparation of the natural products sulcatine G and perforatol.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Polymer Science
Maria A. Bazhenova, Leonid A. Kulikov, Daria A. Makeeva, Anton L. Maximov, Eduard A. Karakhanov
Summary: Bifunctional catalysts based on sulfonated porous aromatic frameworks (PAFs) were used in the hydrodeoxygenation (HDO) of lignin-derived compounds. The results showed that this catalytic system promoted partial hydrogenation of lignin-based compounds, providing a promising route to the selective conversion of lignin model compounds.
Article
Chemistry, Physical
Artemy R. Fatkulin, Oleg I. Afanasyev, Alexey A. Tsygankov, Denis Chusov
Summary: This study demonstrates a significant increase in the catalytic activity of ruthenium catalysts in reductive amination after the addition of iodide to the reaction mixture. High turnover numbers and preparative yields of the products were achieved.
JOURNAL OF CATALYSIS
(2022)
Article
Chemistry, Physical
Noy B. Nechmad, Keren Iudanov, Naziha Tarannam, Victoria Kobernik, Sebastian Kozuch, N. Gabriel Lemcoff
Summary: The ruthenium alkylidene-catalyzed ring-closing metathesis (RCM) of 5-membered rings is highly favored due to entropic and enthalpic contributions. However, the RCM of a hindered diene could only be achieved at high concentrations using a trifluoromethyl sulfur-chelated ruthenium benzylidene catalyst. The addition of ethyl acetate significantly enhanced the catalyst's activity.
Article
Chemistry, Physical
Peiqi Liu, Wanyun Shao, Zhen Yang, Jiuzhong Yang, Liangyuan Jia, Yang Pan, Zhongyue Zhou, Yingquan Chen, Fei Qi
Summary: Through the combination of a low-pressure reactor and an in situ synchrotron vacuum ultraviolet photoionization molecular beam mass spectrometer (SVUV-PI-MBMS), important reactive intermediates can be detected and characterized, and the dynamics of volatile formation can also be studied. The catalytic pyrolysis of furanic compounds over HZSM-5 revealed the production of reactive intermediates such as formaldehyde and acetaldehyde, which were found to be mainly produced through side-chain cracking on the external surface of the zeolite. Reactive methylcyclopenadienes (MCPDs) were also formed and further converted to methylbenzenes (MBs) via ring-expansion.
Article
Chemistry, Organic
Patrick Sand, Bernd Schmidt
Summary: The regioselectivity of two mechanistically distinct alkenylation reactions catalyzed by in situ-formed cationic transition metal complexes was studied using N-allyl-N-phenylethenesulfonamide as a model compound. Orthogonal selectivity was observed for the Ru-catalyzed C-H-activating alkenylation with acetanilides, which occurs preferentially at the electron deficient double bond, and for a Pd-catalyzed Heck-type coupling with arene diazonium salts, which occurs preferentially at the more electron rich double bond of the N-allyl substituent.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Kristine Klimovica, Julius X. Heidlas, Irvin Romero, Thanh V. Le, Olafs Daugulis
Summary: This article reports sandwich diimine-copper(I) catalysts for C(sp(3))-H bond functionalization, demonstrating rare examples of base-metal catalyzed, intermolecular C(sp(3))-H functionalizations using unactivated diazo compounds. The electrophilicity and unique steric environment of the sandwich-copper catalysts are likely reasons for their catalytic efficiency.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Xiuqin Dong, Jiaqi Li, Tianfeng Ma, Lingtao Wang
Summary: In this study, the Fischer-Tropsch synthesis process using a Co catalyst supported by Y-zeolite was simulated, and it was found that the introduction of Y-zeolite enhanced the adsorption capacity of the catalyst and reduced the energy barriers of the CH-CH coupling and C-2-C-4 carbon chain growth process, explaining the high proportion of long carbon chain hydrocarbons in the synthesis products.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Review
Chemistry, Multidisciplinary
Wenting Fang, Anders Riisager
Summary: Catalytic transfer hydrogenation/hydrogenolysis is an economically and environmentally friendly method to valorize renewable compounds derived from biomass. This review focuses on recent progress made on important carbohydrate-derived furanic platform chemicals, highlighting catalyst developments and mechanism explanations. Understanding these features can guide the selection of suitable catalysts for specific transformations, improving the selectivity and yield of products.
Article
Chemistry, Multidisciplinary
M. Pinzon, O. Aviles-Garcia, P. Sanchez, A. Romero, A. R. de la Osa, A. de Lucas-Consuegra
Summary: Novel ruthenium catalysts supported on reduced graphene oxide were synthesized and characterized for COx-free hydrogen generation via catalytic ammonia decomposition. The catalyst's properties were influenced by the metal loading and pre-reducing agent, with the optimal conditions resulting in a high ammonia conversion rate and hydrogen production rate.
SUSTAINABLE CHEMISTRY AND PHARMACY
(2022)
Article
Engineering, Chemical
Maximilian Cohen, Dionisios G. Vlachos
Summary: Mechanistic modeling provides insights into catalytic reactions. The Energy Span Model (ESM) and its modified version (MESA) offer methods to analyze complex reaction networks with parallel pathways. The cycle plot method is proposed for visual reaction pathways analysis. MESA is consistent with microkinetic modeling results and extends the ESM to heterogeneous catalysts using collision theory.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Nanoscience & Nanotechnology
Yung Wei Hsiao, Darien K. Nguyen, Kewei Yu, Weiqing Zheng, Panagiotis Dimitrakellis, Dionisios G. Vlachos
Summary: We use a nonthermal, He/O-2 atmospheric plasma as an efficient method of surface functionalization for activated carbons. Plasma treatment rapidly increases the surface oxygen content of the activated carbon, introducing a diverse range of carbonyl and carboxyl functionalities. This surface functionalization improves the catalytic synthesis, reducing particle size, suppressing agglomerate formation, and increasing metal dispersion, leading to improved yield of biofuel replacement compound.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Chemical
Nawaf M. Alghamdi, Dionisios G. Vlachos, S. Mani Sarathy
Summary: This study presents a thermodynamically consistent, density functional theory (DFT)-based parametrized microkinetic model that predicts CO oxidation on Rh at stoichiometric and lean conditions. The model accurately simulates experimental data and literature data collected under different conditions. This microkinetic mechanism can contribute to optimizing three-way catalysts to reduce CO emissions and propose cheaper alternative catalysts.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Physical
Yilang Liu, Xue Zong, Abhirup Patra, Stavros Caratzoulas, Dionisios G. Vlachos
Summary: Understanding structure-property relationships is crucial for the development of atomically dispersed and sub-nanometer Pt and Pt-Sn cluster catalysts for propane dehydrogenation. This study investigates the effects of Pt nuclearity and Sn heteroatoms on the catalytic activity using density functional theory calculations and microkinetic modeling. It is found that Ptx clusters are prone to sintering, but the addition of Sn improves their stability. Pt1 has the lowest dehydrogenation barriers but is limited by hydrogen blocking. A volcano-like activity-nuclearity relation is observed, with Pt2 being the most active cluster. Moderate addition of Sn depresses Pt activity, while Pt/Sn ratio of 1:1 leads to inactivity. The Pt3Sn1 cluster shows good activity and stability, making it a potential experimental target.
Article
Chemistry, Multidisciplinary
Pavel A. Kots, Panagiota A. Doika, Brandon C. Vance, Sean Najmi, Dionisios G. Vlachos
Summary: In this study, the hydrocracking of high-density polyethylene was investigated using a bifunctional Pt/Al2O3 and modified mordenite acid catalyst. Mass transport limitations affect polymer diffusion into mordenite pores, while initial reaction intermediates are formed on the zeolite's outer surface. Recrystallization and desilication of mordenite improve polymer conversion and shift the product distribution maximum. The nature of mesopores and total Bronsted acidity significantly impact zeolite activity and selectivity, indicating the importance of the hierarchical structure of mesoporous mordenite zeolites in plastic waste hydrocracking.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Fabio Cameli, Panagiotis Dimitrakellis, Dionisios G. Vlachos
Summary: A modular, biphasic plasma reactor is used to convert underutilized gas streams into liquid fuels and hydrogen for decentralized chemical processing. By selectively upgrading ethane into ethanol, methanol, and acetic acid in a catalyst-free, continuous plasma microreactor, a plasma-assisted path is established to generate oxygenates. This process also produces H-2 coproduction as well as CO2 and C2H4. The carbon selectivity in this process can be as high as >70% C2H5OH, CH3OH, and CH3COOH, and up to 1.3 and 1 mu mol min(-1) of liquid C2H5OH and CH3OH can be obtained. This low carbon footprint, electrified, modular, and intensified process has the potential to valorize underutilized shale gas resources in remote areas.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Yuqing Luo, Esun Selvam, Dionisios G. Vlachos, Marianthi Ierapetritou
Summary: The growing amount of plastic waste poses a threat to the environment. Polyethylene terephthalate (PET) is widely used in fibers and packaging, making it one of the most common plastics. Recent research has proposed chemical recycling and upcycling methods to produce valuable products from PET waste. This study evaluates the environmental and economic performance of various technologies, including microwave-assisted heterogeneous glycolysis, through techno-economic analysis and life cycle assessment. The results show that the microwave-assisted glycolysis process can reduce production costs and emissions compared to traditional routes, making it an effective method for handling distributed PET waste.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Borja Hernandez, Pavel Kots, Esun Selvam, Dionisios G. Vlachos, Marianthi G. Ierapetritou
Summary: This study compares the techno-economics and life cycle assessment of different thermochemical depolymerization technologies for generating various products from LDPE waste. Pyrolysis followed by conversion to lubricant oils is the most profitable technology, while hydrogenolysis has the lowest CO2 emissions at large scales. Hydrocracking is environmentally friendly but requires optimization of the supply chain. Gasification and hydrothermal liquefaction have high emissions, requiring carbon capture systems. Lowering sorting costs, collecting waste near big cities, building large plants, and achieving high selectivity to value-added products are critical for successful plastic waste management.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Gwendolyn J. Gregory, Cong Wang, Sunitha Sadula, Sam Koval, Raul F. Lobo, Dionisios G. Vlachos, Eleftherios Terry Papoutsakis
Summary: There is limited research on microbial deconstruction or functionalization of polyolefin's recalcitrant backbone. However, microbes can utilize polyolefin deconstruction products. In this study, researchers combined chemical catalysis and bioconversion to valorize polyethylene (PE) deconstruction products. They found microbial consortia derived from soil from local recycling plants that can utilize the PE-deconstruction product mix as the sole carbon source.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Darien K. Nguyen, Vibin Vargheese, Vinson Liao, Panagiotis Dimitrakellis, Sagar Sourav, Weiqing Zheng, Dionisios G. Vlachos
Summary: The study demonstrates that nonthermal, atmospheric He/O-2 plasma (NTAP) is an efficient and controllable method for removing organic ligands like PVP from nanoparticles, without altering the shape and size of the nanoparticles, making it a more efficient alternative to traditional calcination.
Article
Computer Science, Interdisciplinary Applications
Xue Zong, Jonathan Lym, Dionisios G. Vlachos
Summary: DescMAP is a Python-based software that automates the selection of descriptors, the generation of volcano maps, and the identification of active sites for structure-sensitive reactions. It enables quick screening of potential catalysts and can be applied to other complex chemistries.
COMPUTER PHYSICS COMMUNICATIONS
(2023)
Article
Engineering, Chemical
Arnav Mittal, Souryadeep Bhattacharyya, Matthew Marino, Tai-Ying Chen, Pierre Desir, Marianthi Ierapetritou, Dionisios G. Vlachos
Summary: Liquid-liquid microchannels have high mass transfer rates but low throughput. To increase productivity, scaling up the channels by increasing diameter is crucial. However, predicting flow patterns and mass transfer rates with varying diameter while accounting for solvent effects is lacking in the literature. In this study, we develop machine learning models to predict flow patterns and mass transfer rates, considering solvent properties and channel diameter, using experimental and computational fluid dynamics data combined with literature-mined data.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Cong Wang, Sagar Sourav, Kewei Yu, Yeonsu Kwak, Weiqing Zheng, Dionisios G. Vlachos
Summary: This study successfully electrifies the dry reforming of methane using metal-free doped ceria catalysts and microwave radiation, providing new insights and methods for carbon-free syngas production.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Lei Huang, Chen Li, Zhidong An, Heqi Zhang, Dionisios G. Vlachos, Jiang Li
Summary: In this study, an effective biomass conversion protection strategy was established and an efficient purification method was developed. The effect of protection group on selectivity was investigated under different acidity/basicity conditions, and the positive effect of the protection strategy on photocatalytic oxidation was demonstrated.
Article
Chemistry, Multidisciplinary
Cong Wang, Sagar Sourav, Kewei Yu, Yeonsu Kwak, Weiqing Zheng, Dionisios G. Vlachos
Summary: This study focuses on the decarbonization of Syngas production through the electrification of dry reforming of methane. By selectively coupling microwave radiation to metal-free doped ceria catalysts, excellent performance is achieved. The insights gained from this study can guide the design of catalysts and process intensification for carbon-free syngas production.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)