Article
Chemistry, Organic
V. V. Timoshkina, S. Yudintsev, E. D. Frenkel', A. A. Pimerzin
Summary: In this study, mixed PMoV heteropoly acids with Keggin structures and modified sulfide catalysts were synthesized and their performance in hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrogenation of naphthalene was evaluated. The results showed that modification of the Mo-containing catalysts with vanadium using a solution of mixed heteropoly acids enhanced their catalytic activity and increased the selectivity for the direct hydrodesulfurization route of the DBT HDS reaction.
PETROLEUM CHEMISTRY
(2022)
Article
Chemistry, Physical
Reem Ghubayra, Rachel Hindle, Rana Yahya, Elena F. Kozhevnikova, Ivan Kozhevnikov
Summary: The study utilized Keggin-type heteropoly acids as catalysts for aerobic oxidative desulfurization, showing effective removal of sulfides from model liquid fuel. The catalysts could be reused multiple times without loss of activity, and the proposed reaction mechanism may involve an unbranched radical chain.
Article
Chemistry, Physical
Maximilian Sennerich, Peter G. Weidler, Stefan Heissler, Bettina Kraushaar-Czarnetzki
Summary: The study investigated modified Mo/V/W mixed oxides as a possible alternative to state-of-the-art heteropoly acid catalysts in the partial oxidation of methacrolein to methacrylic acid. Impregnation with cesium and phosphate ions triggered the transformation of mixed oxides into Keggin-type HPA, improving the selectivity to MAA but not surpassing directly synthesized HPAs in terms of activity, MAA selectivity, or stability.
Review
Chemistry, Physical
Shafaq Nisar, Muhammad Asif Hanif, Umer Rashid, Asma Hanif, Muhammad Nadeem Akhtar, Chawalit Ngamcharussrivichai
Summary: The production of fatty acid methyl esters requires the use of cost-effective, environmentally friendly, and effective catalysts. Currently, alkaline and acidic catalysts in both homogeneous and heterogeneous phases are widely used. Promising catalysts include heteropoly acids, polyoxometalate compounds, carbonaceous materials, and vanadium phosphate. Biocatalysts, especially lipase, are also gaining attention for large-scale FAME production. Future directions include exploring the possibilities of these catalysts in biodiesel production.
Article
Chemistry, Physical
Augusto L. P. de Meireles, Kelly A. da Silva Rocha, Elena F. Kozhevnikova, Ivan V. Kozhevnikov, Elena V. Gusevskaya
Summary: The H3PW12O40 heteropoly acid supported on SiO2 as a catalyst and its bulk acidic cesium salt Cs2.5H0.5PW12O40 have been demonstrated to be highly active and recyclable for the Prins cyclization reaction, leading to the efficient synthesis of the valuable floral odorant Florol? from isoprenol and isovaleraldehyde. The use of dimethylcarbonate or diethylcarbonate as green reaction media, along with low catalyst loadings and moderate conditions, contribute to the sustainability of the method.
MOLECULAR CATALYSIS
(2021)
Article
Chemistry, Physical
E. G. Zhizhina, L. L. Gogin
Summary: The study investigates the impact of equipment corrosion products on the physicochemical and catalytic properties of a Pd(II)+HPA-x catalyst used for the oxidation of n-butene to methyl ethyl ketone, while optimizing the composition of the two-component catalyst for pilot testing. Additionally, the thermal stability of the catalyst solution in the presence of transition metal cations has been determined.
KINETICS AND CATALYSIS
(2021)
Article
Chemistry, Organic
Dipak S. Aher, Kiran R. Khillare, Laxmikant D. Chavan, Vinod A. Shelke, Sunil G. Shankarwar
Summary: Vanadium substituted Molybdotungstophosphoric acid (H5PW6Mo4V2O40 center dot 14H(2)O) was found to be an effective solid catalyst for the one-pot synthesis of several quinoxaline derivatives from the condensation reaction between various substituted o-phenylenediamine and various aromatic benzil compounds in ethanol: water (1:1) solvent under reflux conditions. The synthetic route exhibited excellent yield, short reaction time, simple workup procedure, and reusability of the catalyst.
SYNTHETIC COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Michael J. Dzara, Andres O. Godoy, Madeleine Odgaard, Barr Zulevi, Alexey Serov, Jasna Jankovic, Svitlana Pylypenko
Summary: The study investigates the detailed investigation of commercially available mesoporous nitrogen-functionalized carbon supports and platinum nanoparticles-based ORR catalysts, presenting their physicochemical properties and ORR performance in membrane electrode assemblies. The results demonstrate that carbon supports with engineered morphologies and compositions are a promising platform for producing supports and catalysts with tunable properties for various applications.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Peng Zhang, Xiangyang Mao, Rongli Mi, Lu Wang, Bolun Yang
Summary: An effective and environmentally friendly method was proposed to prepare mesoporous SiO(2)encapsulated phosphotungstic acid (HPW) catalysts for alkylation desulfurization of 3-methylthiophene (3-MT). The characterized results showed that the HPW structure was maintained and there was a strong interaction between HPW and SiO2. The catalysts demonstrated superior activity compared to reported SBA-15 encapsulated HPW catalysts, achieving a 99% conversion of 3-MT.
Review
Biochemistry & Molecular Biology
Fabio Moccia, Luca Rigamonti, Alessandro Messori, Valerio Zanotti, Rita Mazzoni
Summary: This review summarizes the approaches for heterogenization of iron catalysts reported in the literature within the last two decades, discussing the utility and critical points of different immobilization strategies.
Article
Chemistry, Physical
Marcio Jose da Silva, Pedro Henrique da Silva Andrade, Vinicius Fernando Coelho Sampaio
Summary: The catalytic activity of transition metal-substituted potassium silicotungstate salts on the oxidation reactions of terpene alcohols was investigated in this work. Among the salts studied, K5SiFeW11O39 showed the highest activity and selectivity, attributed to its highest Lewis acidity.
Review
Chemistry, Applied
Fahimeh Esmi, Venu Babu Borugadda, Ajay K. Dalai
Summary: This review provides a comprehensive overview of the utilization of various types of plant oils and heterogeneous catalysts for biodiesel production. The advantages and challenges of supported heteropoly acid catalysts are highlighted, and methods to improve catalyst activity and reusability are discussed. The review serves to indicate the advances of supported heteropoly acid catalysts as efficient heterogeneous solid acid catalysts over other types of catalysts.
Article
Chemistry, Applied
V. J. Huamani-Melendez, M. A. Mauro, R. Darros-Barbosa
Summary: Commercial Tara gum from three sources was purified by precipitation with isopmpanol and evaluated on the structural, physicochemical and rheological properties. The monosaccharide composition of Tara gum galactomannans showed strong influence of their origin, with intrinsic viscosity being influenced by origin and temperature. The rheological behavior at diluted concentrations resulted in shear thickening fluid.
FOOD HYDROCOLLOIDS
(2021)
Article
Chemistry, Physical
Satoshi Ishikawa, Yudai Yamada, Naoki Kashio, Nagisa Noda, Kosuke Shimoda, Mio Hayashi, Toru Murayama, Wataru Ueda
Summary: The Tri-MoVO catalyst features a crystal structure with hexagonal and heptagonal channels, constructed from Mo6O21 and MO6 units. Introducing W and Cu elements enhances catalytic activity and selectivity, forming a sophisticated crystal structure.
Article
Chemistry, Physical
Leandro M. Acuna, Marcelo D. Cabezas, Rodolfo O. Fuentes, Fernando F. Munoz
Summary: A novel chemical procedure was used to synthesize a homogeneous SMC perovskite at lower temperatures, revealing unexpected oxidation number speciation and a critical modification of the first coordination shell of Mo and Co cations. These findings provide insights into the physicochemical processes of SMC materials, highlighting its catalytic and electrochemical activity for intermediate temperature-SOFC anode application.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)