DOCSLIB.ORG

The Formation of Nitriles in Hydrocarbon-Rich Atmospheres Of

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Formation of Nitriles in Hydrocarbon-Rich Atmospheres Of Acc. Chem. Res. 2001, 34, 699-706 The Formation of Nitriles in (CO2), germane (GeH4), hydrogen sulfide (H2S) as well as the hydrocarbons ethane (C2H6), acetylene (C2H2), ethyl- ene (C2H4), methylacetylene (CH3CCH), propane (C3H8), Hydrocarbon-Rich Atmospheres • and diacetylene (HCCCCH) and the methyl radical ( CH3) of Planets and Their Satellites: have also been found to be present in trace amounts with mole fractions between 10-9 and 10-5.3 Saturn's moon Laboratory Investigations by the Titan has attracted special attention, because Earth and Crossed Molecular Beam Titan are believed to have emerged with similar atmo- 4 spheres from the solar nebula. Molecular nitrogen (N2) Technique and methane (CH4) are the main constituents of Titan's present atmosphere, followed by molecular hydrogen (H2), RALF I. KAISER* nitrogen-bearing molecules, hydrogen cyanide (HCN), Department of Physics, Technical University Chemnitz, dicyan (C2N2), and cyanoacetylene (HCCCN), as well as 09107 Chemnitz, Germany, and Department of Chemistry, the hydrocarbons acetylene (C H ), ethylene (C H ), ethane University of York, York YO10 5DD, U.K. 2 2 2 4 (C2H6), methylacetylene (CH3CCH), propane (C3H8), and 3 NADIA BALUCANI diacetylene (C4H2). Even though the above-mentioned Dipartimento di Chimica, UniversitaÁ di Perugia, nitrilessmolecules containing a cyano (-CN) groups 06123 Perugia, Italy occur only in trace amounts of a few parts per billion, they Received March 13, 2001 are of particular importance because they are thought to be the key intermediates to form biologically relevant ABSTRACT molecules. Nitriles can be hydrolyzed and react via Crossed molecular beam experiments of cyano radicals, CN(X2Σ+), multistep synthesis ultimately to amino acids, thus pro- reacting with unsaturated hydrocarbons have been performed to viding one of the basic ªingredientsº for life.5 As opposed investigate synthetic routes to nitriles formation in hydrocarbon- to Earth, however, the surface temperature of Titan is rich atmospheres of planets and their moons. We have verified that s s all cyano radical reactions with acetylene, ethylene, methylacet- about 94 K too cold for liquid water to exist and the ylene, allene, benzene, and dimethylacetylene proceed without chemical evolution has remained frozen at an early stage. entrance barrier, have exit barriers well below the energy of the As a consequence, the study of the chemistry of Titan's reactant molecules, and are strongly exothermic. The identification atmosphere offers the unique opportunity to reconstruct of the CN versus H atom exchange channel makes these reactions compelling candidates to synthesize unsaturated nitriles in solar the scene of the primordial terrestrial atmosphere and to system environments. Some of these nitriles, hitherto unobserved unveil key concepts about how biologically active mol- in our solar system, now represent an ideal target to be detected ecules and their nitrile precursors were synthesized on - in the future Cassini Huygens mission to Titan. proto-Earth. One of the main basic questions is, how can the nitrile chemistry be initiated in those low-temperature environ- I. Introduction ments? The atmospheres of Titan and the giant gas planets During the past century, the atmospheres of Jupiter, are constantly bombarded with high-energy photons and Saturn, Uranus, and Neptune have been investigated with cosmic ray particles. In the upper layers of Titan's great effort because their atmospheric composition and atmosphere, for example, the energy deposition is mainly chemical evolution are expected to reveal key aspects of from strongly ionizing, high-energy electrons from Sat- 1 prebiotic chemistry of Earth. The Voyager I/II missions urn's magnetosphere and short-wavelength solar ultra- and ground-based telescopes revealed that the atmo- violet photons (λ < 155 nm). Hence, the ionospheric spheres of the giant gas planets are composed primarily chemistry is dominated by ion-molecule reactions.6 2 of the light elements hydrogen and helium; polyatomic However, longer wavelength photons penetrate down to molecules methane (CH4), ammonia (NH3), water (H2O), the stratosphere and photodissociate HCN to yield cyano phosphine (PH3), carbon monoxide (CO), carbon dioxide radicals, CN(X2Σ+). Since the cyano radical concentration profile overlaps with atmospheric regions containing Ralf I. Kasier was born on May 24, 1966, in Unna, Germany. He received his unsaturated hydrocarbons such as acetylene, it has been Ph.D. in chemistry from the University of Mu¨nster (Germany) and did postdoctoral speculated that these radicals react with hydrocarbons to work in Berkeley with Y. T. Lee and A. G. Suits from 1994 to 1997. From 1997 to produce unsaturated nitriles via neutral-neutral reac- 2000, he received a fellowship from the German Research Council (DFG) to 7 perform his Habilitation at the Department of Physics (University of Chemnitz, tions. The potential importance of the cyanopolyynes Germany; D. Gerlich) and Institute of Atomic and Molecular Sciences (Adademia (Hs(CtC)nsCtN) in that environment strongly motivates Sinica, Taiwan; Y. T. Lee). His research interests include chemical reaction laboratory studies, the aim of which is to elucidate their dynamics (gas phase and solid state), planetary chemistry, and laboratory studies routes of formation. relevant to astrochemistry. Laboratory data on the reactions of cyano radicals with Nadia Balucani was born on October 10, 1965, in Perugia, Italy. She received unsaturated hydrocarbons were lacking for a long time, her Ph.D. from the University of Perugia, did postdoctoral work in Berkeley with Prof. R. J. Saykally, and is currently Research Associate in Chemistry at the predominantly due to the experimental difficulty in University of Perugia. preparing a large concentration of CN(X2Σ+) radicals. Two 10.1021/ar000112v CCC: $20.00 2001 American Chemical Society VOL. 34, NO. 9, 2001 / ACCOUNTS OF CHEMICAL RESEARCH 699 Published on Web 08/18/2001 Nitriles Formation in Hydrocarbon-Rich Atmospheres Kaiser and Balucani kinds of experimental information are necessary to es- tablish whether these reactions might synthesize nitriles in low-temperature environments: (i) the values of the reaction rate constants and (ii) the reaction products themselves. Recent kinetic studies on CN reactions with acetylene, methylacetylene, and ethylene at temperatures as low as 13 K have proved that these reactions are indeed very fast and hold rate constants in the gas kinetics order (about 10-10 cm3 s-1).8 Therefore, these experiments have demonstrated that cyano radicals can react at the prevail- ing temperatures of Jupiter (165 K), Saturn (134 K), Uranus (76 K), and Neptune (57 K). However, in those investiga- tions, only the decay rate of the free radical concentration was monitored, and no information on the identity of the reaction products could be given. Because of this limita- tion, systematic laboratory studies to identify the reaction products of cyano radical reactions with unsaturated hydrocarbons are required in order to assess, once and for all, whether these routes of nitrile formation are open FIGURE 1. Schematic top view of the crossed molecular beam in the solar system environments. apparatus. The two pulsed beam source chambers are visible in The crossed molecular beam method is a powerful the top and left parts; in the case of the CN beam source (source experimental technique to provide this complementary I), the carbon rod holder and the incident laser beam are also piece of information. The complex networks of chemical sketched. The chopper wheel, the cold shield, and a sketch of the detector outer chamber are also shown. processes occurring in the planetary atmospheres consist of a series of elementary reactions, most of which are bimolecular collisions between a radical or an atom and II. The Crossed Molecular Beam Approach a closed-shell species. A detailed experimental knowledge The crossed molecular beam (CMB) method with mass- of the elementary processes involved at a fundamental spectrometric detection10 is a versatile technique to study microscopic level is therefore desirable, even if we want elementary reactions under single-collision conditions, simply to assess the nature of the primary reaction thus permitting the elucidation of the chemical dynamics products. Experiments under single-collision conditions andsin the case of polyatomic reactionssthe primary are essential to achieve this, because in a binary collision products. In contrast to bulk experiments, where reactants involving CN radicals and the molecules of a generic are mixed, the main advantage of a crossed beam experi- hydrocarbon, RH, where an intermediate is formed, i.e., ment is the capability to confine the radicals in a separate, CN(X2Σ+) + RH f [RHCN]* f RCN + H, a cyano radical supersonic beam; this implies that the radicals will collide will react only with one single hydrocarbon molecule, and only with the molecules of a second beam at a specific the stabilization of the [RHCN]* intermediate and/or collision energy and crossing angle, therefore ensuring the successive reaction of the primary products will be observation of the consequences of well-defined molec- avoided. Only this requirement can guarantee that the real ular encounters. All the experiments reported here were primary reaction products are identified. Three-body performed by using the 35º crossed molecular beam collisions may occur in dense planetary atmospheres, and machine (Figure 1).11 The apparatus
Load more

Recommended publications
  • A Chemical Kinetics Network for Lightning and Life in Planetary Atmospheres P
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by St Andrews Research Repository The Astrophysical Journal Supplement Series, 224:9 (33pp), 2016 May doi:10.3847/0067-0049/224/1/9 © 2016. The American Astronomical Society. All rights reserved. A CHEMICAL KINETICS NETWORK FOR LIGHTNING AND LIFE IN PLANETARY ATMOSPHERES P. B. Rimmer and Ch Helling School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK; [email protected] Received 2015 June 3; accepted 2015 October 22; published 2016 May 23 ABSTRACT There are many open questions about prebiotic chemistry in both planetary and exoplanetary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life andprebiotic chemistry outside the solar system. We present an ion–neutral chemical network constructed from scratch, STAND2015, that treats hydrogen, nitrogen, carbon, and oxygen chemistry accurately within a temperature range between 100 and 30,000 K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. STAND2015 is successfully tested against atmospheric chemistry models for HD 209458b, Jupiter, and the present-day Earth using a simple one- dimensionalphotochemistry/diffusion code. Our results for the early Earth agree with those of Kasting for CO2,H2, CO, and O2, but do not agree for water and atomic oxygen. We use the network to simulate an experiment where varied chemical initial conditions are irradiated by UV light. The result from our simulation is that more glycine is produced when more ammonia and methane is present.
    [Show full text]
  • House Fly Attractants and Arrestante: Screening of Chemicals Possessing Cyanide, Thiocyanate, Or Isothiocyanate Radicals
    House Fly Attractants and Arrestante: Screening of Chemicals Possessing Cyanide, Thiocyanate, or Isothiocyanate Radicals Agriculture Handbook No. 403 Agricultural Research Service UNITED STATES DEPARTMENT OF AGRICULTURE Contents Page Methods 1 Results and discussion 3 Thiocyanic acid esters 8 Straight-chain nitriles 10 Propionitrile derivatives 10 Conclusions 24 Summary 25 Literature cited 26 This publication reports research involving pesticides. It does not contain recommendations for their use, nor does it imply that the uses discussed here have been registered. All uses of pesticides must be registered by appropriate State and Federal agencies before they can be recommended. CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish or other wildlife—if they are not handled or applied properly. Use all pesticides selectively and carefully. Follow recommended practices for the disposal of surplus pesticides and pesticide containers. ¿/áepé4áaUÁí^a¡eé —' ■ -"" TMK LABIL Mention of a proprietary product in this publication does not constitute a guarantee or warranty by the U.S. Department of Agriculture over other products not mentioned. Washington, D.C. Issued July 1971 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 25 cents House Fly Attractants and Arrestants: Screening of Chemicals Possessing Cyanide, Thiocyanate, or Isothiocyanate Radicals BY M. S. MAYER, Entomology Research Division, Agricultural Research Service ^ Few chemicals possessing cyanide (-CN), thio- cyanate was slightly attractive to Musca domes- eyanate (-SCN), or isothiocyanate (~NCS) radi- tica, but it was considered to be one of the better cals have been tested as attractants for the house repellents for Phormia regina (Meigen).
    [Show full text]
  • Molecular Excitation in the Interstellar Medium: Recent Advances In
    Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes Evelyne Roueff∗,† and François Lique∗,‡ Laboratoire Univers et Théories, Observatoire de Paris, 92190, Meudon, France, and LOMC - UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 540, 76058, Le Havre, France E-mail: [email protected]; [email protected] Contents 1 Introduction 3 2 Collisional excitation 7 2.1 Methods . 9 2.1.1 Theory . 9 2.1.2 Potential energy surfaces . 10 2.1.3 Scattering Calculations . 13 arXiv:1310.8259v1 [physics.chem-ph] 30 Oct 2013 2.1.4 Experiments . 17 2.2 H2, CO and H2O molecules as benchmark systems . 19 2.2.1 H2 ....................................... 19 ∗To whom correspondence should be addressed †Laboratoire Univers et Théories, Observatoire de Paris, 92190, Meudon, France ‡LOMC - UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 540, 76058, Le Havre, France 1 2.2.2 CO . 22 2.2.3 H2O...................................... 27 2.3 Other recent results . 30 2.3.1 CN / HCN / HNC . 31 2.3.2 CS / SiO / SiS / SO / SO2 .......................... 34 2.3.3 NH3 /NH................................... 38 2.3.4 O2 / OH / NO . 40 2.3.5 C2 /C2H/C3 /C4 / HC3N.......................... 41 2.3.6 Complex Organic Molecules : H2CO / HCOOCH3 / CH3OH . 45 + + + + + 2.3.7 Cations : CH / SiH / HCO /N2H / HOCO . 49 + 2.3.8 H3 ...................................... 52 − − 2.3.9 Anions : CN /C2H ............................ 52 2.4 Isotopologues . 55 3 Radiative and chemical excitation 57 3.1 Radiative effects . 57 3.2 Chemical effects . 59 3.3 Examples .
    [Show full text]
  • Arxiv:1510.07052V1 [Astro-Ph.EP] 23 Oct 2015 99 Lae Ta.20,Adrfrne Therein)
    A Chemical Kinetics Network for Lightning and Life in Planetary Atmospheres P. B. Rimmer1 and Ch Helling School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, United Kingdom ABSTRACT There are many open questions about prebiotic chemistry in both planetary and exoplane- tary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life and prebiotic chemistry outside the solar system. We present an ion-neutral chemical network constructed from scratch, Stand2015, that treats hydrogen, nitrogen, carbon and oxygen chemistry accurately within a temperature range between 100 K and 30000 K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. Stand2015 is successfully tested against atmo- spheric chemistry models for HD209458b, Jupiter and the present-day Earth using a simple 1D photochemistry/diffusion code. Our results for the early Earth agree with those of Kasting (1993) for CO2, H2, CO and O2, but do not agree for water and atomic oxygen. We use the network to simulate an experiment where varied chemical initial conditions are irradiated by UV light. The result from our simulation is that more glycine is produced when more ammonia and methane is present. Very little glycine is produced in the absence of any molecular nitrogen and oxygen. This suggests that production of glycine is inhibited if a gas is too strongly reducing. Possible applications and limitations of the chemical kinetics network are also discussed. Subject headings: astrobiology — atmospheric effects — molecular processes — planetary systems 1. Introduction The input energy source and the initial chem- istry have been varied across these different ex- The potential connection between a focused periments.
    [Show full text]
  • Reactivity of N(2D) Atoms and of the Cyano Radical (CN) with Vinyl Cyanide (H2CCHCN) in Titan’S Atmosphere: a Combined Crossed Beam and Theoretical Study
    EPSC Abstracts Vol. 15, EPSC2021-268, 2021 https://doi.org/10.5194/epsc2021-268 Europlanet Science Congress 2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Reactivity of N(2D) atoms and of the cyano radical (CN) with vinyl cyanide (H2CCHCN) in Titan’s atmosphere: a combined crossed beam and theoretical study Demian Marchione1, Luca Mancini1, Pengxiao Liang1, Gianmarco Vanuzzo1, Piergiorgio Casavecchia1, Dimitrios Skouteris2, Marzio Rosi3, and Nadia Balucani1 1Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia, Italy 2Master-Up, Perugia, Italy 3Dipartimento di Ingegneria Civile e Ambientale Università degli Studi di Perugia, Perugia, Italy Several studies have reported model vertical profiles and/or abundance measurements for the main nitrile species observed in Titan’s atmosphere including: hydrogen cyanide (HCN), cyanoacetylene (HC3N), and vinyl cyanide (H2CCHCN) [1-4]. One of the main mechanisms leading to the formation of these nitriles (molecules bearing the CN group) is the reaction of CN radicals with hydrocarbons (molecules with general formula CxHy) involving H elimination (e.g. CN + C2H4=H 2CCHCN + H) or H abstraction (e.g. CN + CH4 = HCN + CH3) [5-9]. In this regard, it is worthwhile to highlight the recent spectroscopic detection of H2CCHCN, obtained using archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), because this species is the best candidate molecule to form stable cell membranes/vesicle structures of
    [Show full text]
  • Arxiv:1606.06230V3 [Physics.Chem-Ph]
    Predissociation of methyl cyanoformate: The HCN and HNC channels Michael J. Wilhelma,∗, Emilio Mart´ınez-Nu´nez˜ b,∗, Jesus´ Gonzalez-V´ azquez´ c, Saulo A. Vazquez´ b, Jonathan M. Smitha, and Hai-Lung Daia aDepartment of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, Pennsylvania 19122, USA. bDepartamento de Qu´ımicaF´ısicaand Centro Singular de Investigaci´onen Qu´ımicaBiol´oxicae Materiais Moleculares (CIQUS), Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Spain. cDepartamento de Qu´ımica,Universidad Aut´onomade Madrid, M´odulo13, 28049 Madrid, Spain. Abstract We present a combined experimental and theoretical investigation of the 193 nm photolysis of the cyano-ester, methyl cyanoformate (MCF). Specifically, nanosecond time-resolved infrared emission spectroscopy was used to monitor the ro-vibrationally excited photoproducts generated in the photolysis reaction. The signal-to-noise of all time-resolved spectra were enhanced using the recently developed algorithm, spectral reconstruction analysis, which allowed observation of previously obscured minor resonances, and revealed new dissociation channels producing HCN and HNC. Spectral fit analysis of the nascent HCN and electronically 2 excited CN(A Π1) resonances yield a lower bound estimate for the HCN quantum yield of ca. 0.42±0.24%. Multi-configuration self-consistent field calculations were used to interrogate the ground and four lowest energy singlet excited states of MCF. At 193 nm, dissociation is predicted to occur predominantly on the repulsive S2 state. Nevertheless, minor pathways leading to the production of highly excited ground state MCF are available via cascading internal conversion from nascent S2 population. An automated transition-state search algorithm was employed to identify the corresponding ground state dissociation channels, and Rice-Ramsperger-Kassel-Marcus and Kinetic Monte Carlo kinetic simulations were used to calculate the associated branching ratios.
    [Show full text]
  • United States Patent Office Patented June 2, 1964
    3,135,788 United States Patent Office Patented June 2, 1964 1. 2 tine is, if pure, a very stable substance. Further we 3,135,788 PREPARATION OF D-CARNT, NE HYDROCLO. found out that by any conventional method for syn RE FROM TRMETHYLAMNE HYDROCLC). thesizing carnitine, a large amount of by-products are un RDE AND EPHALOGENGHYORN avoidably formed, and that the instability of carnitine funzo Noguchi, Kanazawa, and Naoichi Sakota, Nishi would be ascribable to the presence of such by-products nomiya, Japan, assignors to Nihon Zoki Seiyaku Kabu which are practically impossible to remove from carnitine shikikaisha, Osaka, Japan, a corporation of Japan even by recrystallization. As a logical consequence, it No Drawing. Filed July 18, 1960, Ser. No. 43,275 ensues that a synthetic method for preparing carnitine Ciainas priority, application Japan Sept. 28, 1959 must satisfy the following three conditions; namely, i0 Claims. (C. 269-53) O (1) Carnitine should be produced in a high yield, This invention relates to a method for the preparation (2) The amount of by-products accompanying through of DL-carnitine hydrochloride, and in particular, to a all the steps should be minimum, novel synthetic method for preparing DL-carnitine hy (3) Said by-products should be readily removable from drochloride of high purity in a good yield. the final product, carnitine. The chemical nomenclature of said DL-carnitine hy 15 We have accomplished, as a result of numerous experi drochloride is DL-y-trimethyl ammonium-6-hydroxy ments, the method of this invention which satisfies the butyrate hydrochloride represented by the following con above three requirements.
    [Show full text]
  • Theoretical Studies of Ground and Excited State Reactivity
    Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1179 Theoretical Studies of Ground and Excited State Reactivity POORIA FARAHANI ACTA UNIVERSITATIS UPSALIENSIS ISSN 1651-6214 UPPSALA urn:nbn:se:uu:diva-232219 2014 Dissertation presented at Uppsala University to be publicly examined in Häggsalen, Ångström laboratory, Uppsala, Thursday, 30 October 2014 at 13:00 for the degree of Doctor of Philosophy. The examination will be conducted in English. Faculty examiner: Prof Isabelle Navizet (Université PARIS-EST). Abstract Farahani, P. 2014. Theoretical Studies of Ground and Excited State Reactivity. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1179. 86 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9036-2. To exemplify how theoretical chemistry can be applied to understand ground and excited state reactivity, four different chemical reactions have been modeled. The ground state chemical reactions are the simplest models in chemistry. To begin, a route to break down halomethanes through reactions with ground state cyano radical has been selected. Efficient explorations of the potential energy surfaces for these reactions have been carried out using the artificial force induced reaction algorithm. The large number of feasible pathways for reactions of this type, up to eleven, shows that these seemingly simple reactions can be quite complex. This exploration is followed by accurate quantum dynamics with reduced dimensionality for the reaction between − Cl and PH2Cl. The dynamics indicate that increasing the dimensionality of the model to at least two dimensions is a crucial step for an accurate calculation of the rate constant.
    [Show full text]
  • Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen
    Florida International University FIU Digital Commons FIU Electronic Theses and Dissertations University Graduate School 10-24-2013 Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polcyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion Alexander Landera Florida International University, [email protected] DOI: 10.25148/etd.FI13120424 Follow this and additional works at: https://digitalcommons.fiu.edu/etd Part of the Physical Chemistry Commons Recommended Citation Landera, Alexander, "Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polcyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion" (2013). FIU Electronic Theses and Dissertations. 991. https://digitalcommons.fiu.edu/etd/991 This work is brought to you for free and open access by the University Graduate School at FIU Digital Commons. It has been accepted for inclusion in FIU Electronic Theses and Dissertations by an authorized administrator of FIU Digital Commons. For more information, please contact [email protected]. FLORIDA INTERNATIONAL UNIVERSITY Miami, Florida FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND NITROGEN CONTAINING POLYCYCLIC AROMATIC COMPOUNDS IN TITAN’S ATMOSPHERE, THE INTERSTELLAR MEDIUM AND COMBUSTION A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSPHY in CHEMISTRY by Alexander Landera 2013 To: Dean Kenneth G. Furton College of Arts and Sciences This dissertation, written by Alexander Landera, and entitled Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polycyclic Aromatic Compounds in Titan's atmosphere, the Interstellar Medium and Combustion, having been approved in respect to style and intellectual content, is referred to you for judgment. We have read this dissertation and recommend that it be approved.
    [Show full text]
  • The Reductive Decyanation Reaction: an Overview and Recent Developments Jean-Marc Mattalia
    The reductive decyanation reaction: an overview and recent developments Jean-Marc Mattalia To cite this version: Jean-Marc Mattalia. The reductive decyanation reaction: an overview and recent developments. Beilstein Journal of Organic Chemistry, Beilstein-Institut, 2017, 13, pp.267-284. 10.3762/bjoc.13.30. hal-01480621 HAL Id: hal-01480621 https://hal.archives-ouvertes.fr/hal-01480621 Submitted on 14 May 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. The reductive decyanation reaction: an overview and recent developments Jean-Marc R. Mattalia Review Open Access Address: Beilstein J. Org. Chem. 2017, 13, 267–284. Aix-Marseille Univ, CNRS, Centrale Marseille, iSm2, Marseille, France doi:10.3762/bjoc.13.30 Email: Received: 20 October 2016 Jean-Marc R. Mattalia - [email protected] Accepted: 25 January 2017 Published: 13 February 2017 Keywords: Associate Editor: J. A. Murphy α-aminonitrile; decyanation; electron donor; hydride; malononitrile; transition metal catalysis © 2017 Mattalia; licensee Beilstein-Institut. License and terms: see end of document. Abstract This review presents an overview of the reductive decyanation reaction with a special interest for recent developments. This trans- formation allows synthetic chemists to take advantages of the nitrile functional group before its removal.
    [Show full text]
  • Nickel-Catalyzed Reductive Arylation of Redox Active Esters for the Synthesis of -Aryl Nitriles – Role of a Chlorosilane Additive Nicholas W
    Nickel-Catalyzed Reductive Arylation of Redox Active Esters for the Synthesis of -Aryl Nitriles – Role of a Chlorosilane Additive Nicholas W. M. Michel§, Racquel K. Edjoc§, Emmanuel Fagbola§, Jonathan M. E. Hughes‡, Louis- Charles Campeau‡, Sophie A. L. Rousseaux§* AUTHOR ADDRESS § Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, CANADA ‡ Department of Process Research and Development, Merck & Co. Inc., Rahway, New Jersey 07065, United States KEYWORDS nickel catalysis, reductive cross-coupling, chlorosilane, α-aryl nitrile, arylation, radical, NHP ester ABSTRACT: A nickel-catalyzed reductive cross-coupling of redox-active N-hydroxyphthalimide (NHP) esters and iodoarenes for the synthesis of α-aryl nitriles is described. The NHP ester substrate is derived from cyanoacetic acid, which allows for a modular synthesis of substituted -aryl nitriles, an important scaffold in pharmaceutical sciences. Mechanistic studies reveal that decarboxylation of the NHP ester to the reactive radical intermediate is accomplished by a combination of a chlorosilane additive and Zn dust. The reaction exhibits a broad scope as many functional groups are compatible under the reaction conditions, including complex highly functionalized medicinal agents. Scheme 1. α-Aryl nitrile synthesis via cross-coupling intermediates and their prevalence in pharmaceutical agents. Thus, considerable efforts have been dedicated to their synthesis.2 Traditionally, feedstock chemicals such as aliphatic nitriles3 or cyanoacetate salts4 can undergo α-arylation as a nucleophilic reagent in the presence of an aryl(pseudo)halide coupling partner with a transition-metal catalyst such as Pd (Scheme 1a, left). However, these established α-arylation methods require strongly basic reaction conditions and/or high temperatures to generate the nucleophilic coupling partner, which limits both their functional group compatibility and their use in late-stage diversification of complex molecules.
    [Show full text]
  • Quantum Chemical Analysis of Stable Noble Gas Cations for Astrochemical Detection Carlie M
    Georgia Southern University Digital Commons@Georgia Southern University Honors Program Theses 2018 Quantum Chemical Analysis of Stable Noble Gas Cations for Astrochemical Detection Carlie M. Novak Georgia Southern University Follow this and additional works at: https://digitalcommons.georgiasouthern.edu/honors-theses Part of the Physical Chemistry Commons, and the Theory and Algorithms Commons Recommended Citation Novak, Carlie M., "Quantum Chemical Analysis of Stable Noble Gas Cations for Astrochemical Detection" (2018). University Honors Program Theses. 311. https://digitalcommons.georgiasouthern.edu/honors-theses/311 This thesis (open access) is brought to you for free and open access by Digital Commons@Georgia Southern. It has been accepted for inclusion in University Honors Program Theses by an authorized administrator of Digital Commons@Georgia Southern. For more information, please contact [email protected]. Quantum Chemical Analysis of Stable Noble Gas Cations for Astrochemical Detection An Honors Thesis submitted in partial fulfillment of the requirements for Honors in the Department of Chemistry and Biochemistry By Carlie M. Novak Under the mentorship of Dr. Ryan C. Fortenberry ABSTRACT The search for possible, natural, noble gas molecules has led to quantum chemical, spec- troscopic analysis of NeCCH+, ArNH+, ArCCH+, and ArCN+. Each of these systems have been previously shown to be a stable minimum on its respective potential energy surface. However, no spectroscopic data are available for laboratory detection or interstellar obser- vation of these species, and the interstellar medium may be the most likely place, in nature, where these noble gas cations are found. The bent shape of NeCCH+ is confirmed here with a fairly large dipole moment and a bright C { H stretching frequency at 3101.9 cm−1.
    [Show full text]