Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 6 of 6

Full-Text Articles in Engineering

Understanding The Synthesis Of Supported Vanadium Oxide Catalysts Using Chemical Grafting, Alyssa M. Love, Melissa C. Cendejas, Michael P. Hanrahan, Scott L. Carnahan, Pajean Uchupalanun, Aaron J. Rossini, Ive Hermans Nov 2019

Understanding The Synthesis Of Supported Vanadium Oxide Catalysts Using Chemical Grafting, Alyssa M. Love, Melissa C. Cendejas, Michael P. Hanrahan, Scott L. Carnahan, Pajean Uchupalanun, Aaron J. Rossini, Ive Hermans

Chemistry Publications

The complexity of variables during incipient wetness impregnation synthesis of supported metal oxides precludes an in‐depth understanding of the chemical reactions governing the formation of the dispersed oxide sites. This contribution describes the use of vapor phase deposition chemistry (also known as grafting) as a tool to systematically investigate the influence of isopropanol solvent on VO(OiPr)3 anchoring during synthesis of vanadium oxide on silica. We find that the availability of anchoring sites on silica not only depends on the pretreatment of the silica but also on the solvent present. H‐bond donors can reduce the reactivity of ...


Controlling Selectivities In Heterogeneously Catalyzed Aldol Reactions, Koushik Ponnuru Oct 2019

Controlling Selectivities In Heterogeneously Catalyzed Aldol Reactions, Koushik Ponnuru

Doctoral Dissertations

Aldol condensation is an important C-C bond formation reaction in chemical synthesis that finds versatile applications in bulk and fine chemical industries and has the potential for upgrading of biomass to fuels. However, aldol reactions pose a challenge for controlling the product selectivity by forming a mixture of desired and undesired self, cross, and poly-condensation products. Furthermore, a side reaction, the fission of aldol products resulting in an olefin and a carboxylic acid, has garnered attention recently as a route to isobutene from acetone. While a high level of selectivity control is achievable by homogeneous catalysis, selective solid catalysts, which ...


Pd Nanoparticles Supported On Copper Oxide Prepared Via Microwave – Assisted Synthesis: An Efficient Catalyst For Suzuki Cross-Coupling, Hany A. Elazab Dr Sep 2019

Pd Nanoparticles Supported On Copper Oxide Prepared Via Microwave – Assisted Synthesis: An Efficient Catalyst For Suzuki Cross-Coupling, Hany A. Elazab Dr

Chemical Engineering

We report here a scientific investigation of a simple and versatile synthetic rote for the synthesis of palladium nanoparticles decorated with copper oxideand supported on reduced Graphene oxide (rGO) as a highly active catalyst usedfor Suzuki, Heck, and Sonogashira cross coupling reactions with remarkable turnover number (7000) and turnover frequency of 85000 h-1. Pd-CuO nanoparticles supported on reduced Graphene oxide nanosheets (Pd-CuO/rGO) exhibited an outstanding performance through high catalytic activity towards cross coupling reactions. A simple, reproducible, and reliable method was used to prepare this efficient catalyst using microwave irradiation synthetic conditions. The synthesis approach requires simultaneous reduction ...


Facile Synthesis Of Reduced Graphene Oxide-Supported Pd/Cuo Nano-Particles As An Efficient Catalyst For Cross-Coupling Reactions, Hany A. Elazab Dr Sep 2019

Facile Synthesis Of Reduced Graphene Oxide-Supported Pd/Cuo Nano-Particles As An Efficient Catalyst For Cross-Coupling Reactions, Hany A. Elazab Dr

Chemical Engineering

The present communication reports a scientific investigation of a simple and versatile synthetic route for the synthesis of palladium nanoparticles decorated with copper oxide and supported on reduced graphene oxide (rGO). They are used as a highly active catalyst of Suzuki, Heck, and Sonogashira cross coupling reactions with a remarkable turnover number of 7000 and a turnover frequency of 85000 h-1. The Pd-CuO nanoparticles supported on reduced graphene oxide nanosheets (Pd-CuO/rGO) exhibit an outstanding performance through a high catalytic activity towards cross coupling reactions. A simple, reproducible, and reliable method is used to prepare this efficient catalyst using microwave ...


Tin Assisted Fully Exposed Platinum Clusters Stabilized On Defect-Rich Graphene For Dehydrogenation Reaction, Jiayun Zhang, Yuchen Deng, Xiangbin Cai, Yunlei Chen, Mi Peng, Zhimin Jia, Zheng Jiang, Pengju Ren, Siyu Yao, Jinglin Xie, Dequan Xiao, Xiao-Dong Wen, Ning Wang, Hongyang Liu, Ding Ma Mar 2019

Tin Assisted Fully Exposed Platinum Clusters Stabilized On Defect-Rich Graphene For Dehydrogenation Reaction, Jiayun Zhang, Yuchen Deng, Xiangbin Cai, Yunlei Chen, Mi Peng, Zhimin Jia, Zheng Jiang, Pengju Ren, Siyu Yao, Jinglin Xie, Dequan Xiao, Xiao-Dong Wen, Ning Wang, Hongyang Liu, Ding Ma

Chemistry and Chemical Engineering Faculty Publications

Tin assisted fully exposed Pt clusters are fabricated on the core-shell nanodiamond@graphene (ND@G) hybrid support (a-PtSn/ND@G). The obtained atomically dispersed Pt clusters, with an average Pt atom number of 3, were anchored over the ND@Gsupport by the assistance of Sn atoms as a partition agent and through the Pt-C bond between Pt clusters and defect-rich graphene nanoshell. The atomically dispersed Pt clusters guaranteed a full metal availability to the reactants, a high thermal stability, and an optimized adsorption/desorption behavior. It inhibits the side reactions and enhances catalytic performance in direct dehydrogenation of n-butane at ...


Effects Of Chloride Ions In Acid-Catalyzed Biomass Dehydration Reactions In Polar Aprotic Solvents, Max A. Mellmer, Chotitath Sanpitakseree, Benginur Demir, Kaiwen Ma, William A. Elliott, Peng Bai, Robert L. Johnson, Theodore W. Walker, Brent H. Shanks, Robert M. Rioux, Matthew Neurock, James A. Dumesic Mar 2019

Effects Of Chloride Ions In Acid-Catalyzed Biomass Dehydration Reactions In Polar Aprotic Solvents, Max A. Mellmer, Chotitath Sanpitakseree, Benginur Demir, Kaiwen Ma, William A. Elliott, Peng Bai, Robert L. Johnson, Theodore W. Walker, Brent H. Shanks, Robert M. Rioux, Matthew Neurock, James A. Dumesic

Chemical and Biological Engineering Publications

The use of polar aprotic solvents in acid-catalyzed biomass conversion reactions can lead to improved reaction rates and selectivities. We show that further increases in catalyst performance in polar aprotic solvents can be achieved through the addition of inorganic salts, specifically chlorides. Reaction kinetics studies of the Brønsted acid-catalyzed dehydration of fructose to hydroxymethylfurfural (HMF) show that the use of catalytic concentrations of chloride salts leads to a 10-fold increase in reactivity. Furthermore, increased HMF yields can be achieved using polar aprotic solvents mixed with chlorides. Ab initio molecular dynamics simulations (AIMD) show that highly localized negative charge on Cl ...