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Radical In chemistry, radicals (often refered to as free radicals) are atomic or molecular species with unpaired electrons or an otherwise open shell configuration. Free radicals play an important role in a number of biological processes, some of which are necessary for life, such as the intracellular killing of bacteria by neutrophil granulocytes. Because free radicals are necessary for life, the body has a number of mechanisms to minimize free radical induced damage and to repair damage which does occur, such as the enzymes superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. www.ibpassociation.org /encyclopedia/Chemistry/Radical.php   (1289 words)

Radical Reaction Chemistry One radical coupling and homolytic bond fission process is commonly encountered while studying thermodynamics and equilibrium theory, although the radical fragmentation nature of the reaction is usually not discussed. The triphenylmethyl radical adopts a propeller-like conformation, it is non-planar due to steric hindrance imposed by the bulky phenyl ligands. The peroxide radical is able to abstract a hydrogen from a neighbouring hydrocarbon to form the hydroperoxide and another radical centre which propagates the chain reaction. www.meta-synthesis.com /webbook/14_radical/radical.html   (1170 words)

Radical - Wikipedia, the free encyclopedia Radical means pertaining to roots, or at or in the roots. Radical consonant, involves the root of the tongue Radicalization, which refers to the transformation from passiveness or activism to more revolutionary, extremist, or militant postures. en.wikipedia.org /wiki/Radical   (354 words)

FSD - People - James A. Franz   (Site not responding. Last check: 2007-10-10) Jim Franz's accomplishments in the area of kinetics and theory of reactions of organic free radicals have impacted fuel science and fundamental physical organic chemistry. They published the first kinetic studies of fundamental radical reactions related to coal liquefaction using free radical "clocks" and many of the first accurate absolute-rate expressions for reactions of stabilized radicals with sulfur, phosphorus, oxygen, and hydrocarbon systems. Education: B.S. in Chemistry from the University of Washington; Ph.D. in Organic Chemistry from the University of Illinois, Champaign-Urbana. www.pnl.gov /fsd/people/fellows_lab/franz_james.stm   (368 words)

Radical (chemistry) - Search Results - MSN Encarta Radical (chemistry) - Search Results - MSN Encarta Radical (chemistry), also free radical, in chemistry, a molecule with one unpaired electron, or a molecule with two or more unpaired electrons that... There are two broad types of research: the quest for basic knowledge; and applied studies leading to new and improved processes, techniques, and devices. encarta.msn.com /Radical_(chemistry).html   (232 words)

Organosilanes in Radical Chemistry - C. Chatgilialoglu The aim of this book is to offer for the first time a description of silyl radicals within an interdisciplinary context, connecting structural characteristics and chemical properties to their application in different areas of chemistry. This book is essential for anyone working in free radical and/or silicon chemistry as well as for those who want to approach these fields for the first time. Radical chemistry is normally related to tributyl tin hydride. www.organic-chemistry.org /books/reviews/047149870X.shtm   (253 words)

ScienceDaily: Radical (chemistry) Radical (chemistry) -- In chemistry, radicals (often referred to as free radicals) are atomic or molecular species with unpaired electrons on an otherwise open shell configuration. In chemistry and molecular sciences, a molecule is a... The acknowledged leader and standard in general chemistry, this book maintains its effective and proven features—clarity of writing, scientific integrity, currency, strong exercises, visual... www.sciencedaily.com /encyclopedia/Radical_(chemistry)   (1411 words)

IBM Research | Almaden Research Center | Science and Technology | Polymer Science | Living free radical polymerizations   (Site not responding. Last check: 2007-10-10) In preparation, and to further this progress, our scientists are developing a wide range of techniques based on living polymerization methods, and in particular living free radical procedures to control and probe the effect of structure on the performance of these materials. Living free radical polymerization is a recently developed technique for the controlled polymerization of vinyl monomers; this field has witnessed rapid growth in recent years. The significant advantages of this technique permits the preparation of a wide range of different materials which are either difficult to prepare, or not available via other polymerization processes. www.almaden.ibm.com /st/chemistry/ps/living   (250 words)

JCE 2000 (77) 565 [May] General Aspects of Free Radical Chemistry (edited by Z. B. Alfassi) Four chapters on the measurement of rate constants for radical reactions in the gas and liquid phases and on the redox potentials of organic and inorganic molecules survey and compare physical methods for obtaining this data, as well as important experimental variables to be considered. It would provide a superb introduction to radicals in synthesis for a second- or third-year graduate student in synthetic organic chemistry who was preparing for cumulative exams or starting a project along these lines. Some sections, most notably the short chapters on ESR and the thermochemistry of free radicals, are written at a level appropriate for graduate students early in their studies, or even particularly advanced undergraduates. jchemed.chem.wisc.edu:8000 /journal/Issues/2000/May/abs565_2.html   (783 words)

Tropospheric Chemistry Modelling With the exception of 18 aromatic compounds, the chemistry was constructed using the protocol described previously(3). The aromatic chemistry was based on that used in previous work(1,4), but was extended to include the reactions of peroxy radicals with HO2 and NO3, and the permutation reactions of the peroxy radicals. An example of the degradation chemistry constructed using the protocol (3), is displayed schematically in Fig.2. www.chem.leeds.ac.uk /Atmospheric/MCM/main.html   (3297 words)

radical, in chemistry. The Columbia Encyclopedia, Sixth Edition. 2001-05 in chemistry, group of atoms that are joined together in some particular spatial structure and that take part in most chemical reactions as a single unit. (When ions are dealt with, electronic charge must be considered.) In organic chemistry, the term radical is sometimes used synonymously with group; e.g., the group CH is sometimes called the methyl radical instead of the methyl group. Because the term radical easily could be taken to mean a free radical, the term group is preferred by some. www.bartleby.com /65/ra/radical1.html   (213 words)

A modeling study of the nighttime radical chemistry in the lower continental troposphere: 1. Development of a detailed ... A modeling study of the nighttime radical chemistry in the lower continental troposphere: 1. Peroxy radical chemistry is represented with chemical operators and secondary VOCs are lumped into a limited number of surrogate species. Citation: Bey, I. Aumont, and G. Toupance (2001), A modeling study of the nighttime radical chemistry in the lower continental troposphere: 1. www.agu.org /pubs/crossref/2001/2000JD900347.shtml   (453 words)

Radical (chemistry) - Wikipedia, the free encyclopedia Radical alkyl intermediates are stabilized by similar criteria as carbocations: the more substituted the radical center is, the more stable it is. This will direct their reactions: formation of a tertiary radical (R There are two reactions that are observed in the ionic case: the carbonyl is attacked in a direct addition to carbonyl, or the vinyl is attacked in conjugate addition, and in either case, the charge on the nucleophile is taken by the oxygen. The free radical theory of aging proposes that free radicals underlie the aging process itself. en.wikipedia.org /wiki/Radical_(chemistry)   (2508 words)

Uta Wille Group : School of Chemistry : University of Melbourne Radicals are not only very versatile intermediates in organic synthesis but also important species involved in the damage of biological molecules. Upon addition of, for example, O-centred radicals XO• (where X represents inorganic or organic residues) to the C=C triple bond in alkynes, a cascade of radical transfers/cyclizations is initiated, that is terminated through homolytic scission of the O–X bond under release of an unreactive radical X• (see Scheme 1). A close linkage between ageing and oxidative stress is indicated by the observations that reactive oxygen species generated under various conditions of oxidative stress are able to oxidize nucleic acids, proteins and lipids. www.chemistry.unimelb.edu.au /research/programs/wille.php   (349 words)

Dibble Research Group in Chemistry@SUNY-ESF   (Site not responding. Last check: 2007-10-10) Quantum chemistry is used to determine the atmospheric reaction pathways of alkoxy radicals from this critical compound (2-methyl-1,3-butadiene). An important aspect of these radicals is their intramolecular hydrogen bonding, which can lead to some double H-atom jumps. radicals will be generated and their spectra obtained in the near-infrared using cw-cavity ringdown spectroscopy. www.esf.edu /chemistry/dibble/group.htm   (942 words)

An Introduction to Free Radical Chemistry - Book Information The past twenty years has seen an explosion of interest in free radicals, as their pivotal role in both chemistry and biology has come to light. The book provides a gentle, stepwise introduction to the subject, taking the student from the basic principles of radical reactions through to their applications in industry and their role in biological and environmental processes, allowing the relevance of the subject to be grasped more easily. Suitable for advanced level undergraduates and postgraduates in chemistry and biochemistry, the book will also be invaluable for research level scientists requiring an update in the area. www.blackwellpublishing.com /book.asp?ref=0632052929   (151 words)

Countrybookshop.co.uk - Radical Chemistry This work presents that understanding, in which the use of radical reactions is being made in organic synthesis, and in the life sciences, where reactive radicals are recognised as mediators of many disease conditions, and as key players in mechanisms of enzyme action. The subsequent development of radical chemistry was at first very slow, but blossomed with the development of synthetic polymers, especially during and after World War II. In what is now generally understood by radical chemistry we are dealing with reactive, short-lived species which are electrically neutral. www.countrybookshop.co.uk /books/index.phtml?whatfor=0198792891   (217 words)

Expert: Free and Antioxidant Radical Chemistry and Biology Expert He was a pioneer in the use of EPR spin trapping to study free radical chemistry, especially its application to free radical biochemistry and free radical related problems of human health. He has investigated the chemistry and biochemistry of both small molecule antioxidants, such as ascorbate and tocopherol, and antioxidant enzymes. Expert has been a pioneer in the study of free radical chemistry of biologically related free radicals. www.intota.com /viewbio.asp?bioID=603412&perID=107704   (835 words)

Introduction to Radicals A radical is a highly reactive species which has one unpaired electron. Hence many reactions which occur in the gas phase will be radical reactions but some may also occur in solution, especially if the solvent is non-polar and the homolytic fission can be initiated. The reactivity of radicals means that they are less selective than nucleophiles and electrophiles about where they attack a molecule, so this can make them slightly uncontrollable in some circumstances - however many synthetic uses of radicals exist. www.everyscience.com /Chemistry/Organic/Radicals/a.1209.php   (361 words)

Laboratory of Pharmacology and Chemistry: Free Radical Metabolites The evidence for formate -derived radical metabolites in vivo, during acute sodium formate poisoning is provided by ESR spin trapping of the radicals from the metabolism of formate, which are detected in bile and urine as radical adducts. With the aid of the ESR technique, the group has demonstrated the formation of free radicals from rancid unsaturated fatty acids, established the role of hydroxyl radicals in iron and copper toxicity, and implicated the involvement of an ethanol-derived free radical in alcohol-induced cirrhosis of the liver. Recently, free radicals have been a special focus as the final causative molecules in the pathogenesis of acute lung injury caused by P. aeruginosa infection, although there is no direct evidence of free radical generation in lung injury caused by P. aeruginosa in vivo. dir.niehs.nih.gov /dirlpc/freer.htm   (1837 words)

JCE 2004 (81) 1718 [Dec] Radical Reactions in Organic Synthesis (Oxford Chemistry Masters) (Samir Z. Zard) Radical reactions seem to be difficult to control and prone to form multiple products, necessitating tedious separations. Chapter 1 also includes discussions of the differences between ionic and radical reactions, the significance of reaction rate in radical chemistry, and the concept of chain reactions. The author is very clear in the preface that this monograph is derived from his graduate level course in radical reactions and it is at this level—or an advanced course for junior- or senior-level undergraduates—that this book is most appropriately aimed. jchemed.chem.wisc.edu /Journal/Issues/2004/Dec/abs1718.html   (1059 words)

Book An Introduction to Free Radical Chemistry The book provides a gentle, stepwise introduction to the subject, taking the student from the basic principles of radical reactions through to their applications in industry and their role in biological and environmental processes, allowing the relevance of the subject to be grasped more easily. The development of university organic chemistry curricula and the trend towards modularisation of chemistry courses has driven the need for smaller, highly focussed and accessible organic chemistry textbooks, which complement the very detailed “standard texts”, to guide students through the key principles of the subject. The material is organised so that fundamental concepts are introduced early, then built on to provide an overview of the essentials of functional group chemistry and reactivity, leading the student to a solid understanding of the basics of organic chemistry. www-users.york.ac.uk /~chem77/pages/book.htm   (380 words)

Solid Phase Radical Cyclizations and Combinatorial Chemistry Combinatorial chemistry and solid supported reactions have become important recent developments in organic synthesis, representing a new approach to the preparation of libraries of compounds, pharmaceuticals and new organic materials. It is very important to use silyl-tethered radical reactions here because some of these studies are seminal and should use the most reliable radical reactions that have "withstood the test of time" and are the most useful to all researchers in synthetic organic chemistry. Unfortunately, this is an area of free radical reactions that is poorly-developed with only a few, albiet intriguing, efforts in the last 2-3 years. www.chem.ufl.edu /~duran/IGERT/enholm_malacria.htm   (1233 words)

Expert: Free Radical Chemistry and Biology; Oxidation and Antioxidants Expert He has developed techniques for the detection, quantitation, and partial identification of reactive organic radicals in complex gas-phase mixtures, including tobacco smoke, smoke from burning natural and man-made materials, and thermal decomposition of perfluoropolymers. He has applied ESR spin-trapping technology to the study of radicals formed from the reaction of ozone with various organic and biological substrates. He has written a number of reviews relating the free radical chemistry of cigarette smoke to the health effects of smoke. www.intota.com /viewbio.asp?bioID=603607&perID=107734   (1112 words)

Radical Chemistry The mechanism of interaction of light and bleaching agent is very similar to that used by nature in the respiratory chain in living organisms. Radical scavengers prevent radical attack on our skin, which would otherwise provoke ageing or could even severely affect our health. Thanks to a mastering of radical chemistry and radical scavenging processes of our HALS compounds we have even extended their use to flame retarding applications. cibasc.com /zh-cn/index/inn-index/.../inn-rd-plat-radicalchemistry.htm   (373 words)

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