Download or read book Experimental Studies of Hydroxyl Radical Initiated Tropospheric Oxidation of Unsaturated Hydrocarbons written by Buddhadeb Ghosh and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The tropospheric oxidation of unsaturated hydrocarbons is a central issue in atmospheric chemistry. These hydrocarbons are emitted into the atmosphere from both natural and anthropogenic sources, and their atmospheric oxidation leads to different atmospheric pollutants, including ground level ozone, photochemical smog and secondary organic aerosols. Isoprene and 1,3-butadiene represent a biogenic and an anthropogenic hydrocarbon, respectively, which primarily undergo electrophilic addition of OH radical, followed by chain propagating radical reactions. Their oxidation is the major source for ground level ozone formation in both rural and urban area and understanding their chemistry is essential for regional air quality modeling. Until recently, most of the studies of isoprene chemistry have been non-isomer specific, reflecting the reactivity of combined pathways and therefore were insensitive to specific details of the isomeric pathways. An isomeric selective approach to studying unsaturated hydrocarbon oxidation is described in this dissertation. A synthesized precursor, whose photolysis can provide a route to the formation of energy selected single isomer in the isoprene oxidation pathway, enables the study of important channels that are difficult to unravel in non isomer specific experiments. The major addition channel in OH isoprene oxidation has been studied following the isomeric selective approach and using Laser Photolysis-Laser Induced Fluorescence (LP-LIF) as the primary experimental technique. The study reveals important information about the oxidative chemistry of the [delta]-peroxy radicals, accounting for about 20% of missing carbon balance in isoprene oxidation, and isomeric specific rate constants. A similar approach was applied to study the oxidation of 1,3-butadiene, and the photolytic precursor for the dominant hydroxy alkyl isomer in the OH initiated oxidation of 1,3-butadiene was synthesized. The subsequent experiments and analysis revealed detailed information about the oxidative chemistry accounting for approximately 26% of the missing chemistry. Finally, non isomeric selective OH cycling experiments were carried out on the1,3-butadiene system. By analyzing the OH cycling data with the combined information obtained from the isomeric specific studies of the two isomeric channels of 1,3-butadiene oxidation, the relative branching between the two isomeric channels of OH-1,3-butadiene oxidation was determined.
Download or read book The Hydroxyl Radical Initiated Oxidation of Unsaturated Hydrocarbons in the Troposphere written by Erin Elizabeth Tullos and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Isoprene is the dominant non-methane organic compound emitted by vegetation into the atmosphere, with a global emission rate of ~ 500 Tg yr-1. Its oxidation serves as a major source of ground level ozone in North America during the summer months. Despite the significant impact on tropospheric chemistry, questions remain concerning the detailed oxidation mechanism. The initial step in the mechanism is the addition of OH to form four distinct isomers. The relative branching between these isomers influences the distribution of the final products. I present a comprehensive investigation into the mechanistic details of early steps in the oxidation mechanism of unsaturated hydrocarbons in the troposphere and employ theoretical and experimental techniques. To understand the detailed kinetics of the initial OH addition to unsaturated hydrocarbons, I first present a model developed for the ethylene-OH system. I present the details of a robust two-transition state model. I extend the developed two-transition state model to the case of OH addition to isoprene. Excellent agreement with observed temperature and pressure dependent rate constants affords a high confidence level in understanding of the kinetics and in the calculated branching ratio of the initial OH addition step. I then focus attention on the subsequent reactivity of the OH-isoprene adducts. Until recently, all four of the OH-isoprene adducts were supposed to have reacted with O2 via addition to form alkylperoxy radicals. Previous computational results suggest that two of the OH-isoprene adducts undergo an intramolecular cyclic isomerization followed by hydrogen abstraction by O2 to form stable carbonyl compounds. I have synthesized photolytic precursors, presenting a novel approach to probe the subsequent reactivity of individual hydroxyalkyl radicals. Initial verification of the cyclic isomerization pathway involved synthesis of the photolytic precursor corresponding to the 1,3-butadiene-OH adduct. A culmination of theoretical and experimental techniques allowed verification of the cyclic isomerization pathway. I synthesized the photolytic precursor, which provided a single isoprene-OH adduct. Employing laser photolysis/laser induced fluorescence, time-dependent multiplexed mass spectrometry, velocity map ion imaging, and theoretical techniques, we present the full characterization of the reactivity of the single isoprene-OH adduct in the presence of O2.
Download or read book Mechanistic Studies on the OH initiated Atmospheric Oxidation of Selected Aromatic Hydrocarbons written by Sascha Nehr and published by Forschungszentrum Jülich. This book was released on 2012 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kinetic and Mechanistic Studies of the Hydroxyl Radical Initiated Photo oxidation of Saturated Hydrocarbons Under Simulated Atmospheric Conditions written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Volatile Organic Compounds in the Atmosphere written by Ralf Koppmann and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Every day, large quantities of volatile organic compounds (VOCs) are emitted into the atmosphere from both anthropogenic and natural sources. The formation of gaseous and particulate secondary products caused by oxidation of VOCs is one of the largest unknowns in the quantitative prediction of the earth’s climate on a regional and global scale, and on the understanding of local air quality. To be able to model and control their impact, it is essential to understand the sources of VOCs, their distribution in the atmosphere and the chemical transformations which remove these compounds from the atmosphere. In recent years techniques for the analysis of organic compounds in the atmosphere have been developed to increase the spectrum of detectable compounds and their detection limits. New methods have been introduced to increase the time resolution of those measurements and to resolve more complex mixtures of organic compounds. Volatile Organic Compounds in the Atmosphere describes the current state of knowledge of the chemistry of VOCs as well as the methods and techniques to analyse gaseous and particulate organic compounds in the atmosphere. The aim is to provide an authoritative review to address the needs of both graduate students and active researchers in the field of atmospheric chemistry research.
Download or read book Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-23 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the eleventh in a series of evaluated sets of rate constants and photochemical cross sections compiled by the NASA Panel for Data Evaluation. The primary application of the data is in the modeling of stratospheric processes, with special emphasis on the ozone layer and its possible perturbation by anthropogenic and natural phenomena. Demore, W. B. and Sander, S. P. and Golden, D. M. and Hampson, R. F. and Kurylo, M. J. and Howard, C. J. and Ravishankara, A. R. and Kolb, C. E. and Molina, M. J. Jet Propulsion Laboratory NASA-CR-198863, JPL-PUBL-94-26, NAS 1.26:198863 NAS7-1260; RTOP 464-41-04-01-00...
Download or read book The Mechanisms of Atmospheric Oxidation of the Aromatic Hydrocarbons written by Jack G. Calvert and published by Oxford University Press. This book was released on 2002-02-14 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text reviews many of the aspects of the chemistry of the aromatic hydrocarbons and a consensus evaluation of the data by seven of the leading atmospheric scientists. The book covers topics ranging from the relative importance of the compounds in ozone and haze development to methods of estimating elemantary rate coefficients based on structural features of the compounds to mechanisms of aerosol generation and atmostpheric reaction of the polycyclic compounds to photochemical processes. It identifies features of the aromatic hydrocarbons requiring further study and appendicies give the structural formulas and nomenclature of the compounds reviewed in the book.
Download or read book Organic Peroxy Radicals written by P. D. Lightfoot and published by . This book was released on 1992 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanisms of Atmospheric Oxidation of the Oxygenates written by Jack Calvert and published by Oxford University Press. This book was released on 2011-08-01 with total page 1634 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prepared by an international team of eminent atmospheric scientists, Mechanisms of Atmospheric Oxidation of the Oxygenates is an authoritative source of information on the role of oxygenates in the chemistry of the atmosphere. The oxygenates, including the many different alcohols, ethers, aldehydes, ketones, acids, esters, and nitrogen-atom containing oxygenates, are of special interest today due to their increased use as alternative fuels and fuel additives. This book describes the physical properties of oxygenates, as well as the chemical and photochemical parameters that determine their reaction pathways in the atmosphere. Quantitative descriptions of the pathways of the oxygenates from release or formation in the atmosphere to final products are provided, as is a comprehensive review and evaluation of the extensive kinetic literature on the atmospheric chemistry of the different oxygenates and their many halogen-atom substituted analogues. This book will be of interest to modelers of atmospheric chemistry, environmental scientists and engineers, and air quality planning agencies as a useful input for development of realistic modules designed to simulate the atmospheric chemistry of the oxygenates, their major oxidation products, and their influence on ozone and other trace gases within the troposhere.
Download or read book Chemical Processes in Atmospheric Oxidation written by Georges Le Bras and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxidation and removal of atmospheric constituents involve complex sequences of reactions which can lead to the production of photo-oxidants such as ozone. In order to understand and model these complex reaction sequences, it is necessary to have a comprehensive understanding of reaction mechanisms and accurate estimates of kinetic parameters for relevant gas-phase atmospheric reactions. This book presents recent advances in the field and includes the following topics: e.g. the oxidation of simple organic compounds, NOx kinetics and mechanisms, OH radical production and rate constants for the OH attack on more complex organic compounds, peroxy and alkoxy radical reactions, photo-oxidation of aromatic and biogenic compounds, and the interaction between radical species.
Download or read book Mechanisms of Atmospheric Oxidation of the Alkanes written by Jack G Calvert and published by Oxford University Press. This book was released on 2008-09-15 with total page 1005 pages. Available in PDF, EPUB and Kindle. Book excerpt: An international team of eminent atmospheric scientists have prepared Mechanisms of Atmospheric Oxidation of the Alkanes as an authoritative source of information on the role of alkanes in the chemistry of the atmosphere. The book includes the properties of the alkanes and haloalkanes, as well as a comprehensive review and evaluation of the existing literature on the atmospheric chemistry of the alkanes and their major atmospheric oxidation products, and the various approaches now used to model the alkane atmospheric chemistry. Comprehensive coverage is given of both the unsubstituted alkanes and the many haloalkanes. All the existing quality measurements of the rate coefficients for the reactions of OH, Cl, O(3P), NO3, and O3 with the alkanes, the haloalkanes, and their major oxidation products have been reviewed and evaluated. The expert authors then give recommendations of the most reliable kinetic data. They also review the extensive literature on the mechanisms and rates and modes of photodecomposition of the haloalkanes and the products of atmospheric oxidation of the alkanes and the haloalkanes, and make recommendations for future use by atmospheric scientists. The evaluations presented allow an extrapolation of the existing kinetic and photochemical data to those alkanes and haloalkanes that are as yet unstudied. The current book should be of special interest and value to the modelers of atmospheric chemistry as a useful input for development of realistic modules designed to simulate the atmospheric chemistry of the alkanes, their major oxidation products, and their influence on ozone and other trace gases within the troposphere.
Download or read book The Mechanisms of Pyrolysis Oxidation and Burning of Organic Materials written by Leo Aloysius Wall and published by . This book was released on 1972 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Oxidation Processes for Water and Wastewater Treatment written by Simon Parsons and published by IWA Publishing. This book was released on 2004-03-01 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: The suitability of Advanced Oxidation Processes (AOPs) for pollutant degradation was recognised in the early 1970s and much research and development work has been undertaken to commercialise some of these processes. AOPs have shown great potential in treating pollutants at both low and high concentrations and have found applications as diverse as ground water treatment, municipal wastewater sludge destruction and VOCs control. Advanced Oxidation Processes for Water and Wastewater Treatment is an overview of the advanced oxidation processes currently used or proposed for the remediation of water, wastewater, odours and sludge. The book contains two opening chapters which present introductions to advanced oxidation processes and a background to UV photolysis, seven chapters focusing on individual advanced oxidation processes and, finally, three chapters concentrating on selected applications of advanced oxidation processes. Advanced Oxidation Processes for Water and Wastewater Treatment will be invaluable to readers interested in water and wastewater treatment processes, including professionals and suppliers, as well as students and academics studying in this area. Dr Simon Parsons is a Senior Lecturer in Water Sciences at Cranfield University with ten years' experience of industrial and academic research and development.
Download or read book Encyclopedia of Atmospheric Sciences written by Gerald R. North and published by Elsevier. This book was released on 2014-09-14 with total page 2874 pages. Available in PDF, EPUB and Kindle. Book excerpt: Encyclopedia of Atmospheric Sciences, Second Edition, Six Volume Set is an authoritative resource covering all aspects of atmospheric sciences, including both theory and applications. With more than 320 articles and 1,600 figures and photographs, this revised version of the award-winning first edition offers comprehensive coverage of this important field. The six volumes in this set contain broad-ranging articles on topics such as atmospheric chemistry, biogeochemical cycles, boundary layers, clouds, general circulation, global change, mesoscale meteorology, ozone, radar, satellite remote sensing, and weather prediction. The Encyclopedia is an ideal resource for academia, government, and industry in the fields of atmospheric, ocean, and environmental sciences. It is written at a level that allows undergraduate students to understand the material, while providing active researchers with the latest information in the field. Covers all aspects of atmospheric sciences—including both theory and applications Presents more than 320 articles and more than 1,600 figures and photographs Broad-ranging articles include topics such as atmospheric chemistry, biogeochemical cycles, boundary layers, clouds, general circulation, global change, mesoscale meteorology, ozone, radar, satellite remote sensing, and weather prediction An ideal resource for academia, government, and industry in the fields of atmospheric, ocean, and environmental sciences
Download or read book Kinetics and Mechanisms of the Gas phase Reactions of the Hydroxyl Radical with Organic Compounds written by Roger Atkinson and published by American Institute of Physics. This book was released on 1989 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Autoxidation in Food and Biological Systems written by M.G. Simic and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: The material presented in this book deals with basic mechanisms of free radical reactions in autoxidation processes and anitoxidant suppression of autoxidation of foods, biochemical models and biologi cal systems. Autoxidation in foods and corresponding biological effects are usually approached separately although recent mechanistic developments in the biochemistry and free radical chemistry of per oxides and their precursors tend to bring these two fields closer. Apparent ability of antioxidants in diets to reduce the inci dence of cancer has resulted in scrutiny of autoxidized products and their precursors as possibly toxic, mutagenic and carcinogenic agents. Mechanisms of any of these effects have been barely ad dressed. Yet we know now that free radicals, as esoteric as they were only a few decades ago, are being discovered in foods, biochem ical and biological systems and do play a role in the above-mentioned causalities. The purpose of the Workshop and the resulting book was to give a unifying approach towards study of beneficial and deleterious effects of autoxidation, based on rigorous scientific considerations. It is our hope that the material presented in this book will not only provide a review of the "state of the art" of autoxidation and anti oxidants, but also reflect the interaction which occurred during the Workshop between workers using model sytems, and food and biological systems.
Download or read book Air Pollution the Automobile and Public Health written by Sponsored by The Health Effects Institute and published by National Academies Press. This book was released on 1988-01-01 with total page 703 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The combination of scientific and institutional integrity represented by this book is unusual. It should be a model for future endeavors to help quantify environmental risk as a basis for good decisionmaking." â€"William D. Ruckelshaus, from the foreword. This volume, prepared under the auspices of the Health Effects Institute, an independent research organization created and funded jointly by the Environmental Protection Agency and the automobile industry, brings together experts on atmospheric exposure and on the biological effects of toxic substances to examine what is knownâ€"and not knownâ€"about the human health risks of automotive emissions.
