Download or read book Methane Mono oxidation Electrocatalysis by Palladium and Platinum Salts written by Rebecca Soyoung Kim and published by . This book was released on 2020 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Selective oxidation of methane to methanol would enable better utilization of natural gas resources. Many homogeneous metal ions activate methane under mild conditions, but turning this reactivity into catalysis requires a viable oxidation step. Electrochemistry offers unique advantages in this regard, and this thesis demonstrates two mechanistically distinct approaches for methane functionalization electrocatalysis. Following the first approach, a novel high-valent Pd complex with exceptional methane functionalization reaction rates is electrochemically generated in fuming sulfuric acid. We present a structural model of this complex as a Pd[superscript III] dimer with a Pd–Pd bond and a 5-fold O-atom sulfate/bisulfate coordination environment at each Pd atom. We also discover, using EPR spectroscopy, a mixed-valent Pd2[superscript II][superscript III] complex in the electrochemical oxidation sequence. From these and redox potential measurements, a comprehensive thermodynamic landscape for the oxidation of Pd[superscript II] to Pd[superscript III]2 emerge for the first time, and the critical role of M–M and M–L bonding in driving the electrochemical self-assembly of Pd[superscript III]2 is exposed. Building on these structural studies, we arrive at a mechanistic model for methane functionalization by Pd[superscript III]2 that simultaneously yields methyl bisulfate (MBS) and methanesulfonic acid (MSA). Rate-limiting H atom abstraction by Pd[superscript III]2 and product bifurcation from the methyl radical intermediate is proposed based on experimentally determined rate laws and observations with radical scavengers and initiators. DFT calculations likewise support a shared outer-sphere proton-coupled electron transfer (PCET) reaction for the generation of both products. Following the second approach for methane functionalization electrocatalysis, we establish an electrochemical solution to the long-standing oxidant problem of Shilov’s Pt[superscript II] catalyst. Inner-sphere electron transfer facilitates the electrochemical oxidation of Pt[superscript II] to Pt[superscript IV] on Cl-adsorbed platinum electrodes without concomitant methanol oxidation. The favorable catalytic property of this electrode is exploited for the continuous regeneration of the Pt[superscript IV] oxidant during Pt[superscript II]-catalyzed methane functionalization. The critical Pt[superscript II]/[superscript IV] ratio is maintained via dynamic modulation of the electric current and in situ monitoring of the solution redox potential. Thereby, we show stable and sustained turnover of Shilov’s catalyst for the first time.

Download or read book Structure sensitivity of Methane Oxidation Over Platinum and Palladium written by Michael Lawrence Young and published by . This book was released on 1989 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrocatalytic Oxidation of Alcohols Using Platinum and Palladium Nanoporous Solids written by Margaretta Mary Dimos and published by . This book was released on 2011 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Methane Conversion by Oxidative Processes written by Wolf and published by Springer. This book was released on 2013-11-13 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: A reasonable case could be made that the scientific interest in catalytic oxidation was the basis for the recognition of the phenomenon of catalysis. Davy, in his attempt in 1817 to understand the science associated with the safety lamp he had invented a few years earlier, undertook a series of studies that led him to make the observation that a jet of gas, primarily methane, would cause a platinum wire to continue to glow even though the flame was extinguished and there was no visible flame. Dobereiner reported in 1823 the results of a similar investigation and observed that spongy platina would cause the ignition of a stream of hydrogen in air. Based on this observation Dobereiner invented the first lighter. His lighter employed hydrogen (generated from zinc and sulfuric acid) which passed over finely divided platinum and which ignited the gas. Thousands of these lighters were used over a number of years. Dobereiner refused to file a patent for his lighter, commenting that "I love science more than money." Davy thought the action of platinum was the result of heat while Dobereiner believed the ~ffect ~as a manifestation of electricity. Faraday became interested in the subject and published a paper on it in 1834; he concluded that the cause for this reaction was similar to other reactions.

Download or read book Kinetics of Complete Methane Oxidation on Palladium Model Catalysts written by and published by . This book was released on 2004 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Methane Oxidation on Platinum Catalysts Investigated by Spatially Resolved Methods written by and published by . This book was released on 2012 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Complete Oxidation of Methane on Palladium Catalysts Final Report written by Fabio H. Ribeiro and published by . This book was released on 2003 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the final report for grant DE-FG02-00ER15026. It summarizes all the accomplishments in these 8 sections: (1) Adaptations on Existing Unit and Construction of New Unit; (2) Turnover Rate and Reaction Orders for the Complete Oxidation of Methane on a Palladium Foil in Excess Dioxygen; (3) Surface area increase on Pd foils after oxidation in excess methane; (4) UV Raman spectroscopic study of hydrogen bonding in gibbsite and bayerite between 93 and 453 K; (5) Coverage of Palladium Catalysts by Oxidized Silicon During Complete Oxidation of Methane; (6) Kinetics of Methane Oxidation under lean conditions over Pd and PdO; (7) An Explanation for the Hysteresis on the Oxidation of Methane; and (8) Structure of Pd(111) after oxidation in O{sub 2}.

Download or read book Methane Oxidation Over Palladium based Catalyst for Exhaust gas After treatment written by Andreas Gremminger and published by . This book was released on 2020* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Partial Oxidation of Methane Over Halogen Modified Palladium Catalyst written by Mahendra Kumar Dosi and published by . This book was released on 1978 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Catalytic Partial Oxidation of Methane Using Platinum nickel Dual Bed Reactors written by Christa Bell and published by . This book was released on 2006 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The catalytic partial oxidation of methane to produce synthesis gas using a platinum/nickel dual bed reactor has been shown to have high conversions and selectivity of synthesis gas products, hydrogen and carbon monoxide. In this work the relative length of the platinum and nickel in the dual bed reactor is investigated experimentally and a model describing the nickel portion of the dual bed catalyst is developed. The model uses simplified flow conditions, experimentally determined temperature profiles and an elementary reaction mechanism to describe the nickel bed of the reactor. The rate parameters of the elementary reaction in the mechanism are determined using theoretical methods. Unity Bond Index - Quadratic Exponential Potential (UBI-QEP) is used to determine the activation energy and thermodynamic consistency is forced to produce a set of preexponential factors." --

Download or read book Catalytic Oxidation of Methane Over Alumina Supported Palladium Oxides written by Jacqueline Michelle McGuire and published by . This book was released on 2018 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Catalytic Oxidation of Methane Over Supported Palladium Catalysts written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Kinetics of Methane Oxidation on Supported Palladium Catalyst Systems written by Sarveswara Sastry Peri and published by . This book was released on 1995 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Catalytic Oxidation of Methane Over Supported Palladium Catalysts microform written by Wei Ye and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1999 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Activation Behavior of a Silica supported Palladium Catalyst During Methane Oxidation written by Jane M. Lamanna and published by . This book was released on 1996 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Palladium and Platinum Complexes for the Oxidation of Small Molecules written by David Michael Pearson and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Palladium is a versatile metal used prominently in synthesis. The rapid growth of palladium oxidation chemistry in the past decade has spurred a number of new processes that allow for the selective oxidation of substrates under mild conditions. This growth, specifically in the field of aerobic alcohol oxidation, attracted our attention, with the hope that it would provide new catalysts for use in direct methanol fuel cells. Toward that goal we developed a new cationic palladium complex, [(neocuproine)Pd(OAc)]2[OTf]2, which shows unprecedented initial turnover frequencies for aerobic alcohol oxidation at room temperature. However, catalyst lifetimes are limited due to the generation of reactive partially reduced oxygen species that promote oxidation of the ligand and deactivation of the catalyst. The use of milder oxidant like benzoquinone extended catalyst lifetimes prompting a further exploration of the substrate scope. Oxidation of glycerol proceeds exclusively at the secondary alcohol to yield dihydroxyacetone. Other 1,2-diols also favors oxidation of the secondary alcohol. Methanol oxidation proceeds at a much slower rate, but yields methyl formate with selectivities greater than 90 %. The mechanism for this process was probed through the use of model studies and isotopic labels suggesting the transient generation and oxidation of methyl hemiformal. In a parallel effort toward the extension of catalyst lifetimes, a number of new oxidatively resistant ligands were synthesized and used toward the formation of palladium catalysts that exhibit extended catalyst lifetimes. Additional efforts have focused on the use of similar catalyst for the oxidative carbonylation of 1,2- and 1,3-diols to yield 5-membered and 6-membered cyclic carbonates in the presence of N-chlorosuccinimide, iodosylbenzene, or dichloroisocyanuric acid. Finally, a new platinum dimer containing a trimethylplatinum unit and bridging amides was synthesized and characterized. Its reactivity toward the reductive elimination of ethane of methanol derivatives was explored. Additional work with known platinum dimers suggests these species, upon addition of silver triflate, facilitates the C-H activation of a number of unactivated arenes and promotes the C-H functionalization of propargyl aryl ethers.

Download or read book Springer Handbook of Aerogels written by Michel A. Aegerter and published by Springer Nature. This book was released on 2023-10-01 with total page 1778 pages. Available in PDF, EPUB and Kindle. Book excerpt: This indispensable handbook provides comprehensive coverage of the current state-of-the-art in inorganic, organic, and composite aerogels – from synthesis and characterization to cutting-edge applications and their potential market impact. Built upon Springer’s successful Aerogels Handbook published in 2011, this handbook features extensive revisions and timely updates, reflecting the changes in this fast-growing field. Aerogels are the lightest solids known to man. Up to 1000 times lighter than glass and with a density only four times that of air, they possess extraordinarily high thermal, electrical, and acoustic insulation properties, and boast numerous entries in Guinness World Records. Originally based on silica, R&D efforts have extended this class of materials to incorporate non-silicate inorganic oxides, natural and synthetic organic polymers, carbon, metal, and ceramic materials. Composite systems involving polymer-crosslinked aerogels and interpenetrating hybrid networks have been developed and exhibit remarkable mechanical strength and flexibility. Even more exotic aerogels based on clays, chalcogenides, phosphides, quantum dots, and biopolymers such as chitosan are opening new applications for the construction, transportation, energy, defense and healthcare industries. Applications in electronics, chemistry, mechanics, engineering, energy production and storage, sensors, medicine, nanotechnology, military and aerospace, oil and gas recovery, thermal insulation, and household uses are being developed. Readers of this fully updated and expanded edition will find an exhaustive source for all aerogel materials known today, their fabrication, upscaling aspects, physical and chemical properties, and the most recent advances towards applications and commercial use. This key reference is essential reading for a combined audience of graduate students, academic researchers, and industry professionals.