DOCSLIB.ORG

Critically Evaluated Thermochemical Properties of Polycyclic Aromatic Hydrocarbons

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Critically Evaluated Thermochemical Properties of Polycyclic Aromatic Hydrocarbons Critically Evaluated Thermochemical Properties of Polycyclic Aromatic Hydrocarbons María Victoria Rouxa… and Manuel Temprado Instituto de Química Física “Rocasolano,” CSIC, Serrano 119, 28006 Madrid, Spain James S. Chickos Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri 63121-4499, USA Yatsuhisa Nagano Research Center for Molecular Thermodynamics, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan ͑Received 1 October 2007; revised manuscript received 5 June 2008; accepted 11 June 2008; published online 23 October 2008͒ Experimental thermochemical properties of benzene, toluene, and 63 polycyclic aro- matic hydrocarbons, published within the period 1878–2008 ͑over 350 references͒, are reported. Available experimental data for the enthalpies of combustion used to calculate enthalpies of formation in the condensed state, combined with sublimation, vaporization, and fusion enthalpies, are critically evaluated. Whenever possible, recommended values for these thermochemical properties and for the enthalpies of formation in the gas state at T=298.15 K are provided. © 2008 American Institute of Physics. ͓DOI: 10.1063/1.2955570͔ CONTENTS 7.3.2. Enthalpy of fusion............... 1875 7.3.3. Enthalpy of vaporization. ......... 1876 7.3.4. Enthalpy of sublimation........... 1876 1. Introduction.............................. 1864 7.3.5. Summary....................... 1876 2. Enthalpies of Formation.................... 1865 7.4. Indane.............................. 1877 3. Phase Change Enthalpies................... 1866 7.4.1. Enthalpy of formation ͑liquid͒...... 1877 3.1. Vaporization Enthalpies................ 1867 7.4.2. Enthalpy of fusion............... 1877 3.2. Sublimation enthalpies................. 1867 7.4.3. Enthalpy of vaporization. ......... 1878 3.3. Fusion Enthalpies..................... 1867 7.4.4. Enthalpy of sublimation........... 1878 3.4. Estimated Properties................... 1868 7.4.5. Summary....................... 1878 4. Evaluation of the Data..................... 1868 7.5. Naphthalene.......................... 1879 ͑ ͒ 5. Recommendations. ........................ 1869 7.5.1. Enthalpy of formation solid ...... 1879 7.5.2. Enthalpy of fusion............... 1880 6. Compounds Evaluated..................... 1869 7.5.3. Enthalpy of vaporization. ......... 1880 7. Data Sheets and Recommendations........... 1870 7.5.4. Enthalpy of sublimation........... 1881 7.1. Benzene............................. 1870 7.5.5. Summary....................... 1882 ͑ ͒ 7.1.1. Enthalpy of formation liquid ...... 1870 7.6. Biphenylene. ......................... 1883 7.1.2. Enthalpy of fusion............... 1871 7.6.1. Enthalpy of formation ͑solid͒...... 1883 7.1.3. Enthalpy of vaporization. ......... 1871 7.6.2. Enthalpy of fusion............... 1883 7.1.4. Enthalpy of sublimation........... 1872 7.6.3. Enthalpy of vaporization. ......... 1884 7.1.5. Summary....................... 1872 7.6.4. Enthalpy of sublimation........... 1884 7.2. Toluene............................. 1873 7.6.5. Summary....................... 1884 ͑ ͒ 7.2.1. Enthalpy of formation liquid ...... 1873 7.7. Acenaphthylene....................... 1885 7.2.2. Enthalpy of fusion............... 1874 7.7.1. Enthalpy of formation ͑solid͒...... 1885 7.2.3. Enthalpy of vaporization. ......... 1874 7.7.2. Enthalpy of fusion............... 1885 7.2.4. Enthalpy of sublimation........... 1874 7.7.3. Enthalpy of vaporization. ......... 1886 7.2.5. Summary....................... 1875 7.7.4. Enthalpy of sublimation........... 1886 7.3. Indene.............................. 1875 7.7.5. Summary....................... 1887 ͑ ͒ 7.3.1. Enthalpy of formation liquid ...... 1875 7.8. Acenaphthene. ...................... 1887 7.8.1. Enthalpy of formation ͑solid͒...... 1887 a͒ Author to whom correspondence should be addressed; electronic mail: 7.8.2. Enthalpy of fusion............... 1888 [email protected]. © 2008 American Institute of Physics. 7.8.3. Enthalpy of vaporization. ......... 1888 0047-2689/2008/37„4…/1855/142/$42.001855 J. Phys. Chem. Ref. Data, Vol. 37, No. 4, 2008 1856 ROUX ET AL. 7.8.4. Enthalpy of sublimation........... 1889 7.18. 1-Phenylnaphthalene................... 1912 7.8.5. Summary....................... 1889 7.18.1. Enthalpy of formation ͑solid͒...... 1912 7.9. Biphenyl............................ 1890 7.18.2. Enthalpy of fusion............... 1912 7.9.1. Enthalpy of formation ͑solid͒...... 1890 7.18.3. Enthalpy of vaporization. ......... 1912 7.9.2. Enthalpy of fusion............... 1890 7.18.4. Enthalpy of sublimation........... 1912 7.9.3. Enthalpy of vaporization. ......... 1891 7.18.5. Summary....................... 1913 7.9.4. Enthalpy of sublimation........... 1891 7.19. 11H-Benzo͓a͔fluorene................. 1913 7.9.5. Summary....................... 1892 7.19.1. Enthalpy of formation ͑solid͒...... 1913 7.10. Fluorene............................. 1893 7.19.2. Enthalpy of fusion............... 1913 7.10.1. Enthalpy of formation ͑solid͒...... 1893 7.19.3. Enthalpy of vaporization. ......... 1913 7.10.2. Enthalpy of fusion............... 1893 7.19.4. Enthalpy of sublimation........... 1914 7.10.3. Enthalpy of vaporization. ......... 1894 7.19.5. Summary....................... 1914 7.10.4. Enthalpy of sublimation........... 1894 7.20. 11H-Benzo͓b͔fluorene................. 1914 7.10.5. Summary....................... 1895 7.20.1. Enthalpy of formation ͑solid͒...... 1914 7.11. Diphenylmethane...................... 1895 7.20.2. Enthalpy of fusion............... 1915 7.11.1. Enthalpy of formation ͑liquid͒...... 1895 7.20.3. Enthalpy of vaporization. ......... 1915 7.11.2. Enthalpy of formation ͑solid͒...... 1896 7.20.4. Enthalpy of sublimation........... 1915 7.11.3. Enthalpy of fusion............... 1896 7.20.5. Summary....................... 1916 7.11.4. Enthalpy of vaporization. ......... 1896 7.21. Naphthacene......................... 1916 7.11.5. Enthalpy of sublimation........... 1897 7.21.1. Enthalpy of formation ͑solid͒...... 1916 7.11.6. Summary....................... 1897 7.21.2. Enthalpy of fusion............... 1916 7.12. Pyracyclene.......................... 1898 7.21.3. Enthalpy of vaporization. ......... 1917 7.12.1. Enthalpy of formation ͑solid͒...... 1898 7.21.4. Enthalpy of sublimation........... 1917 7.12.2. Enthalpy of fusion............... 1898 7.21.5. Summary....................... 1917 7.12.3. Enthalpy of vaporization. ......... 1898 7.22. Benz͓a͔anthracene..................... 1918 7.12.4. Enthalpy of sublimation........... 1898 7.22.1. Enthalpy of formation ͑solid͒...... 1918 7.12.5. Summary....................... 1899 7.22.2. Enthalpy of fusion............... 1918 7.13. Anthracene........................... 1899 7.22.3. Enthalpy of vaporization. ......... 1919 7.13.1. Enthalpy of formation ͑solid͒...... 1899 7.22.4. Enthalpy of sublimation........... 1919 7.13.2. Enthalpy of fusion............... 1900 7.22.5. Summary....................... 1919 7.13.3. Enthalpy of vaporization. ......... 1900 7.23. Triphenylene......................... 1920 7.13.4. Enthalpy of sublimation........... 1901 7.23.1. Enthalpy of formation ͑solid͒...... 1920 7.13.5. Summary....................... 1902 7.23.2. Enthalpy of fusion............... 1920 7.14. Phenanthrene. ....................... 1902 7.23.3. Enthalpy of vaporization. ......... 1921 7.14.1. Enthalpy of formation ͑solid͒...... 1902 7.23.4. Enthalpy of sublimation........... 1921 7.14.2. Enthalpy of fusion............... 1903 7.23.5. Summary....................... 1922 7.14.3. Enthalpy of vaporization. ......... 1904 7.24. Chrysene............................ 1922 7.14.4. Enthalpy of sublimation........... 1904 7.24.1. Enthalpy of formation ͑solid͒...... 1922 7.14.5. Summary....................... 1905 7.24.2. Enthalpy of fusion............... 1922 7.15. Pyracene. .......................... 1906 7.24.3. Enthalpy of vaporization. ......... 1923 7.15.1. Enthalpy of formation ͑solid͒...... 1906 7.24.4. Enthalpy of sublimation........... 1923 7.15.2. Enthalpy of fusion............... 1906 7.24.5. Summary....................... 1924 7.15.3. Enthalpy of vaporization. ......... 1906 7.25. Benzo͓c͔phenanthrene.................. 1924 7.15.4. Enthalpy of sublimation........... 1906 7.25.1. Enthalpy of formation ͑solid͒...... 1924 7.15.5. Summary....................... 1907 7.25.2. Enthalpy of fusion............... 1925 7.16. Pyrene.............................. 1907 7.25.3. Enthalpy of vaporization. ......... 1925 7.16.1. Enthalpy of formation ͑solid͒...... 1907 7.25.4. Enthalpy of sublimation........... 1925 7.16.2. Enthalpy of fusion............... 1907 7.25.5. Summary....................... 1925 7.16.3. Enthalpy of vaporization. ......... 1908 7.26. p-Terphenyl.......................... 1926 7.16.4. Enthalpy of sublimation........... 1909 7.26.1. Enthalpy of formation ͑solid͒...... 1926 7.16.5. Summary....................... 1909 7.26.2. Enthalpy of fusion............... 1926 7.17. Fluoranthene......................... 1910 7.26.3. Enthalpy of vaporization. ......... 1927 7.17.1. Enthalpy of formation ͑solid͒...... 1910 7.26.4. Enthalpy of sublimation........... 1927 7.17.2. Enthalpy of fusion............... 1910 7.26.5. Summary....................... 1927 7.17.3. Enthalpy of vaporization. ......... 1911 7.27. o-Terphenyl.......................... 1928 7.17.4. Enthalpy of sublimation........... 1911 7.27.1. Enthalpy of formation ͑solid͒...... 1928 7.17.5. Summary....................... 1912 7.27.2. Enthalpy of fusion..............
Load more

Recommended publications
  • May-June 2013 OUTLOOK on Volume 35 No
    CHEMISTRY International The News Magazine of IUPAC May-June 2013 OUTLOOK ON Volume 35 No. 3 LATIN AMERICA Neglected Tropical Diseases INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY Green Chemistry in Teaching From the Editor CHEMISTRY International ay is a month of many celebrations. As we have mentioned several Mtimes before in CI, 20 May is World Metrology Day, which com- The News Magazine of the International Union of Pure and memorates the signing by representatives of 17 nations of The Metre Applied Chemistry (IUPAC) Convention on that day in 1875. This year, the theme is “Measurements in Daily Life”—see more at www.worldmetrologyday.org. www.iupac.org/publications/ci While living in the states, but having grown up in Belgium, I have found that measurements in my daily life can be quite bewildering. A simple Managing Editor: Fabienne Meyers length mentioned in inches, a travel distance Production Editor: Chris Brouwer referred to in miles, a quantity in a cook book Design: pubsimple specified in spoons or cups, or my own weight blurred in pounds on my bathroom scale make All correspondence to be addressed to: no sense to me. And, it is beyond me that this Fabienne Meyers “New World” is stuck in a nonmetric system. If IUPAC, c/o Department of Chemistry on 20 May I can convince just one friend that Boston University SI is the way to go, even for daily usage, it is Metcalf Center for Science and Engineering worth celebrating! 590 Commonwealth Ave. There are many more international and world days in May, several that Boston, MA 02215, USA are even recognized by the UN or UNESCO.
    [Show full text]
  • Principles of Surface Chemistry Central to the Reactivity of Organic Semiconductor Materials
    Loyola University Chicago Loyola eCommons Dissertations Theses and Dissertations 2018 Principles of Surface Chemistry Central To the Reactivity of Organic Semiconductor Materials Gregory J. Deye Follow this and additional works at: https://ecommons.luc.edu/luc_diss Part of the Inorganic Chemistry Commons Recommended Citation Deye, Gregory J., "Principles of Surface Chemistry Central To the Reactivity of Organic Semiconductor Materials" (2018). Dissertations. 2952. https://ecommons.luc.edu/luc_diss/2952 This Dissertation is brought to you for free and open access by the Theses and Dissertations at Loyola eCommons. It has been accepted for inclusion in Dissertations by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. Copyright © 2018 Gregory J Deye LOYOLA UNIVERSITY CHICAGO PRINCIPLES OF SURFACE CHEMISTRY CENTRAL TO THE REACTIVITY OF ORGANIC SEMICONDUCTOR MATERIALS A DISSERTATION SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY PROGRAM IN CHEMISTRY BY GREGORY J. DEYE CHICAGO, IL AUGUST 2018 Copyright by Gregory J. Deye, 2018 All rights reserved. ACKNOWLEDGMENTS The scientific advances and scholarly achievements presented in this dissertation are a direct result of excellent mentorships, collaborations, and relationships for which I am very grateful. I thank my advisor, Dr. Jacob W. Ciszek, for his professionalism in mentorship and scientific discourse. He took special care in helping me give more effective presentations and seek elegant solutions to problems. It has been a privilege to work at Loyola University Chicago under his direction. I would also like to express gratitude to my committee members, Dr.
    [Show full text]
  • Synthesis and Properties of Corannulene Derivatives: Journey to Materials Chemistry and Chemical Biology
    Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2008 Synthesis and properties of corannulene derivatives: journey to materials chemistry and chemical biology Hayama, Tomoharu Abstract: Corannulene, also called as [5]-circulene, is a C20H10 fragment of buckminsterfullerene, C60. The most interesting property of corannulene is probably its bowl structure and bowl-to-bowl inversion. The unique curvature has many possiblities for applications in different fields. Today, large-scale synthesis of corannulene is possible and thus, the time has come to exploit its physical properties. This disserta- tion is divided into four areas: 1) efficient synthesis of sym-pentaarylsubstituedcorannulene derivatives, 2) solvent effect on the bowl inversion, 3) development of the method for solution-phase nanotube syn- thesis, and 4) designing a corannulene-based synthetic receptor. sym-pentaarylsubstituedcorannulenes are quite attractive compounds because of their five-fold symmetry and curvature. The efficient synthesis has been accomplished from sym-pentachlorocorannulene with the coupling reaction using N-heterocyclic carbene ligands in a moderately good yield in spite of its five low-reactive chlorides. The inversion energies of some sym-pentaarylsubstituedcorannulenes have been investigated in different types of sol- vent. The variable temperature 1H-NMR spectra were measured, and line shape analysis or coalescence approximation were used to evaluate the rate parameters. This experiment suggested endo-group inter- actions of those compounds and shows influences of solvent polarity or volume on the inversion energies. In addition, the bowl depths will also be compared and discussed using the crystallographic structural data. The high-energy per-ethynylated polynuclear compound decapentynyl-corannulene has been pre- pared via aryl-alkyne coupling chemistry of decachlorocorannulene.
    [Show full text]
  • Exploring Antiaromaticity in Single-Molecule Junctions Formed
    Nanoscale View Article Online PAPER View Journal | View Issue Exploring antiaromaticity in single-molecule junctions formed from biphenylene derivatives† Cite this: Nanoscale, 2019, 11, 20659 Markus Gantenbein,‡a Xiaohui Li, ‡b Sara Sangtarash, *‡c Jie Bai, b Gunnar Olsen, a Afaf Alqorashi,c Wenjing Hong, *b Colin J. Lambert *c and Martin R. Bryce *§a We report the synthesis of a series of oligophenylene-ethynylene (OPE) derivatives with biphenylene core units, designed to assess the effects of biphenylene antiaromaticity on charge transport in molecular junctions. Analogues with naphthalene, anthracene, fluorene and biphenyl cores are studied for compari- son. The molecules are terminated with pyridyl or methylthio units. Single-molecule conductance data were obtained using the mechanically controllable break junction (MCBJ) technique. It is found that when electrons pass from one electrode to the other via a phenylene ring, the electrical conductance is almost independent of the nature of the pendant π-systems attached to the phenylene ring and is rather insensi- Creative Commons Attribution 3.0 Unported Licence. tive to antiaromaticity. When electrons pass through the cyclobutadiene core of the biphenylene unit, transport is sensitive to the presence of the relatively weak single bonds connecting the two phenylene rings of biphenylene, which arise from partial antiaromaticity within the cyclobutadiene core. This leads to Received 25th June 2019, a negligible difference in the molecular conductance compared to the fluorene or biphenyl analogues Accepted 26th August 2019 which have standard single bonds. This ability to tune the conductance of molecular cores has no ana- DOI: 10.1039/c9nr05375a logue in junctions formed from artificial quantum dots and reflects the quantum nature of electron trans- rsc.li/nanoscale port in molecular junctions, even at room temperature.
    [Show full text]
  • Determination of Sublimation Enthalpy and Vapor Pressure for Inorganic and Metal-Organic Compounds by Thermogravimetric Analysis∗
    Connexions module: m33649 1 Determination of Sublimation Enthalpy and Vapor Pressure for Inorganic and Metal-Organic Compounds by Thermogravimetric Analysis∗ Andrew R. Barron This work is produced by The Connexions Project and licensed under the Creative Commons Attribution License y 1 Introduction Metal compounds and complexes are invaluable precursors for the chemical vapor deposition (CVD) of metal and non-metal thin lms. In general, the precursor compounds are chosen on the basis of their relative volatility and their ability to decompose to the desired material under a suitable temperature regime. Unfortunately, many readily obtainable (commercially available) compounds are not of sucient volatility to make them suitable for CVD applications. Thus, a prediction of the volatility of a metal-organic compounds as a function of its ligand identity and molecular structure would be desirable in order to determine the suitability of such compounds as CVD precursors. Equally important would be a method to determine the vapor pressure of a potential CVD precursor as well as its optimum temperature of sublimation. It has been observed that for organic compounds it was determined that a rough proportionality exists between a compound's melting point and sublimation enthalpy; however, signicant deviation is observed for inorganic compounds. Enthalpies of sublimation for metal-organic compounds have been previously determined through a vari- ety of methods, most commonly from vapor pressure measurements using complex experimental systems such as Knudsen eusion, temperature drop microcalorimetry and, more recently, dierential scanning calorime- try (DSC). However, the measured values are highly dependent on the experimental procedure utilized. For example, the reported sublimation enthalpy of Al(acac)3 (Figure 1a, where M = Al, n = 3) varies from 47.3 to 126 kJ/mol.
    [Show full text]
  • Polycyclic Aromatic Hydrocarbon Structure Index
    NIST Special Publication 922 Polycyclic Aromatic Hydrocarbon Structure Index Lane C. Sander and Stephen A. Wise Chemical Science and Technology Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899-0001 December 1997 revised August 2020 U.S. Department of Commerce William M. Daley, Secretary Technology Administration Gary R. Bachula, Acting Under Secretary for Technology National Institute of Standards and Technology Raymond G. Kammer, Director Polycyclic Aromatic Hydrocarbon Structure Index Lane C. Sander and Stephen A. Wise Chemical Science and Technology Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899 This tabulation is presented as an aid in the identification of the chemical structures of polycyclic aromatic hydrocarbons (PAHs). The Structure Index consists of two parts: (1) a cross index of named PAHs listed in alphabetical order, and (2) chemical structures including ring numbering, name(s), Chemical Abstract Service (CAS) Registry numbers, chemical formulas, molecular weights, and length-to-breadth ratios (L/B) and shape descriptors of PAHs listed in order of increasing molecular weight. Where possible, synonyms (including those employing alternate and/or obsolete naming conventions) have been included. Synonyms used in the Structure Index were compiled from a variety of sources including “Polynuclear Aromatic Hydrocarbons Nomenclature Guide,” by Loening, et al. [1], “Analytical Chemistry of Polycyclic Aromatic Compounds,” by Lee et al. [2], “Calculated Molecular Properties of Polycyclic Aromatic Hydrocarbons,” by Hites and Simonsick [3], “Handbook of Polycyclic Hydrocarbons,” by J. R. Dias [4], “The Ring Index,” by Patterson and Capell [5], “CAS 12th Collective Index,” [6] and “Aldrich Structure Index” [7]. In this publication the IUPAC preferred name is shown in large or bold type.
    [Show full text]
  • Estimation of Enthalpy of Bio-Oil Vapor and Heat Required For
    Edinburgh Research Explorer Estimation of Enthalpy of Bio-Oil Vapor and Heat Required for Pyrolysis of Biomass Citation for published version: Yang, H, Kudo, S, Kuo, H-P, Norinaga, K, Mori, A, Masek, O & Hayashi, J 2013, 'Estimation of Enthalpy of Bio-Oil Vapor and Heat Required for Pyrolysis of Biomass', Energy & Fuels, vol. 27, no. 5, pp. 2675-2686. https://doi.org/10.1021/ef400199z Digital Object Identifier (DOI): 10.1021/ef400199z Link: Link to publication record in Edinburgh Research Explorer Document Version: Early version, also known as pre-print Published In: Energy & Fuels General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 04. Oct. 2021 Estimation of Enthalpy of Bio-oil Vapor and Heat Required for Pyrolysis of Biomass Hua Yang,† Shinji Kudo,§ Hsiu-Po Kuo,‡ Koyo Norinaga, ξ Aska Mori, ξ Ondřej Mašek,|| and Jun-ichiro Hayashi †, ξ, §, * †Interdisciplinary Graduate School of Engineering Sciences, Kyushu University,
    [Show full text]
  • An Indicator of Triplet State Baird-Aromaticity
    inorganics Article The Silacyclobutene Ring: An Indicator of Triplet State Baird-Aromaticity Rabia Ayub 1,2, Kjell Jorner 1,2 ID and Henrik Ottosson 1,2,* 1 Department of Chemistry—BMC, Uppsala University, Box 576, SE-751 23 Uppsala, Sweden; [email protected] (R.A.); [email protected] (K.J.) 2 Department of Chemistry-Ångström Laboratory Uppsala University, Box 523, SE-751 20 Uppsala, Sweden * Correspondence: [email protected]; Tel.: +46-18-4717476 Received: 23 October 2017; Accepted: 11 December 2017; Published: 15 December 2017 Abstract: Baird’s rule tells that the electron counts for aromaticity and antiaromaticity in the first ππ* triplet and singlet excited states (T1 and S1) are opposite to those in the ground state (S0). Our hypothesis is that a silacyclobutene (SCB) ring fused with a [4n]annulene will remain closed in the T1 state so as to retain T1 aromaticity of the annulene while it will ring-open when fused to a [4n + 2]annulene in order to alleviate T1 antiaromaticity. This feature should allow the SCB ring to function as an indicator for triplet state aromaticity. Quantum chemical calculations of energy and (anti)aromaticity changes along the reaction paths in the T1 state support our hypothesis. The SCB ring should indicate T1 aromaticity of [4n]annulenes by being photoinert except when fused to cyclobutadiene, where it ring-opens due to ring-strain relief. Keywords: Baird’s rule; computational chemistry; excited state aromaticity; Photostability 1. Introduction Baird showed in 1972 that the rules for aromaticity and antiaromaticity of annulenes are reversed in the lowest ππ* triplet state (T1) when compared to Hückel’s rule for the electronic ground state (S0)[1–3].
    [Show full text]
  • Ammonia, Anhydrous Ama
    AMMONIA, ANHYDROUS AMA CAUTIONARY RESPONSE INFORMATION 4. FIRE HAZARDS 7. SHIPPING INFORMATION 4.1 Flash Point: 7.1 Grades of Purity: Commercial, industrial, Common Synonyms Liquefied compressed Colorless Ammonia odor Not flammable under conditions likely to refrigeration, electronic, and metaflurgical Liquid ammonia gas be encountered grades all have purity greater than 99.5% 4.2 Flammable Limits in Air: 15.50%- 7.2 Storage Temperature: Ambient for pressurized 27.00% ammonia; low temperature for ammonia at Floats and boils on water. Poisonous, visible vapor cloud is produced. 4.3 Fire Extinguishing Agents: Stop flow of atmospheric pressure Avoid contact with liquid and vapor. Keep people away. gas or liquid. Let fire burn. 7.3 Inert Atmosphere: No requirement Wear goggles, self-contained breathing apparatus, and rubber overclothing (including gloves). 4.4 Fire Extinguishing Agents Not to Be 7.4 Venting: Safety relief 250 psi for ammonia Stop discharge if possible. Used: None under pressure. Pressure-vacuum for Stay upwind and use water spray to ``knock down'' vapor. 4.5 Special Hazards of Combustion ammonia at atmospheric pressure. Call fire department. Products: Not pertinent Isolate and remove discharged material. 7.5 IMO Pollution Category: Currently not available 4.6 Behavior in Fire: Not pertinent Notify local health and pollution control agencies. 7.6 Ship Type: 2 4.7 Auto Ignition Temperature: 1204°F Protect water intakes. 7.7 Barge Hull Type: 2 4.8 Electrical Hazards: Class I, Group D Combustible. 4.9 Burning Rate: 1 mm/min. Fire 8. HAZARD CLASSIFICATIONS Wear goggles, self-contained breathing apparatus, and rubber over- 4.10 Adiabatic Flame Temperature: Currently clothing (including gloves).
    [Show full text]
  • HEATS of COMBUSTION of DIAMOND and of GRAPHITE by Ralph S
    r---------------___........,._ . _____~ ~_ U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS RESEARCH PAPER RP1140 Part of Journal of Research of the }.{ational Bureau of Standards, Volume 21, October 1938 HEATS OF COMBUSTION OF DIAMOND AND OF GRAPHITE By Ralph S. Jessup ABSTRACT Measurements were made of the heats of combustion of one artificial graphite, two natural graphites, and two samples of diamond. The bomb calorimeter used was calibrated electrically and by means of benzoic acid. The amount of reaction in each combustion experiment was determined from the mass of carbon dioxide formed. This method of determining the amount of reaction automatically eliminates the effect of unburned carbon and of some impurities. It was found, however, that results for different samples did not agree unless the samples were purified. Two methods of purification were used: (a) heating in vacuo to 1,800° C and (b) treatment with hydrochloric and hydrofluoric acids and subsequent heating in vacuo to 200° C to remove traces of the acids. Both methods yielded graphite containing only small amounts of impurities. The mean value obtained for the heat of combustion (-/lH) of the purified graphites in oxygen at 25° C and a constant pressure of 1 atmosphere to form gaseous carbon dioxide at the same temperature and pressure was 393.396 international kilojoules per mole (44.010 g of CO2). The maximum deviation of the mean value for anyone of the purified samples from this value was 0.021 percent. The two samples of diamond, purified by treatment with aqueous hydrochloric and hydrofluoric acids and subsequently heated in vacuo to about 570° C, had average particle sizes of 2.5 I'- and 39.5 1'-, respectively, and yielded the following respective mean values for the heat of combustion (-/lH) at 25° C and 1 atmos­ phere, in oxygen to form gaseous carbon dioxide: 395.771 and 395.287 interna­ tional kilojoules per mole.
    [Show full text]
  • SAFETY DATA SHEET Cyclopentane
    SAFETY DATA SHEET Cyclopentane Section 1. Identification GHS product identifier : Cyclopentane Chemical name : cyclopentane Other means of : cyclopentane (dot); pentamethylene identification Product use : Synthetic/Analytical chemistry. Synonym : cyclopentane (dot); pentamethylene SDS # : 001124 Supplier's details : Airgas USA, LLC and its affiliates 259 North Radnor-Chester Road Suite 100 Radnor, PA 19087-5283 1-610-687-5253 24-hour telephone : 1-866-734-3438 Section 2. Hazards identification OSHA/HCS status : This material is considered hazardous by the OSHA Hazard Communication Standard (29 CFR 1910.1200). Classification of the : FLAMMABLE LIQUIDS - Category 2 substance or mixture AQUATIC HAZARD (ACUTE) - Category 3 AQUATIC HAZARD (LONG-TERM) - Category 3 GHS label elements Hazard pictograms : Signal word : Danger Hazard statements : Highly flammable liquid and vapor. May form explosive mixtures in Air. Harmful to aquatic life with long lasting effects. Precautionary statements General : Read label before use. Keep out of reach of children. If medical advice is needed, have product container or label at hand. Prevention : Wear protective gloves. Wear eye or face protection. Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking. Use explosion- proof electrical, ventilating, lighting and all material-handling equipment. Use only non- sparking tools. Take precautionary measures against static discharge. Keep container tightly closed. Avoid release to the environment. Response : IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower. Storage : Store in a well-ventilated place. Keep cool. Disposal : Dispose of contents and container in accordance with all local, regional, national and international regulations. Hazards not otherwise : None known.
    [Show full text]
  • Exploitation of Baird Aromaticity and Clar's Rule for Tuning The
    Article Exploitation of Baird Aromaticity and Clar’s Rule for Tuning the Triplet Energies of Polycyclic Aromatic Hydrocarbons Felix Plasser Department of Chemistry, Loughborough University, Loughborough LE11 3TU, UK; [email protected] Abstract: Polycyclic aromatic hydrocarbons (PAH) are a prominent substance class with a variety of applications in molecular materials science. Their electronic properties crucially depend on the bond topology in ways that are often highly non-intuitive. Here, we study, using density functional theory, the triplet states of four biphenylene-derived PAHs finding dramatically different triplet excitation energies for closely related isomeric structures. These differences are rationalised using a qualitative description of Clar sextets and Baird quartets, quantified in terms of nucleus independent chemical shifts, and represented graphically through a recently developed method for visualising chemical shielding tensors (VIST). The results are further interpreted in terms of a 2D rigid rotor model of aromaticity and through an analysis of the natural transition orbitals involved in the triplet excited states showing good consistency between the different viewpoints. We believe that this work constitutes an important step in consolidating these varying viewpoints of electronically excited states. Keywords: aromaticity; antiaromaticity; chemical shift; hydrocarbons, benzene; p-conjugated systems Citation: Plasser, F. Exploitation of Baird Aromaticity and Clar’s Rule for 1. Introduction Tuning the Triplet Energies of Polycyclic Aromatic Hydrocarbons. Polycyclic aromatic hydrocarbons (PAHs) are a fascinating class of molecules provid- Chemistry 2021, 3, 532–549. http:// ing versatile organic semi-conductors [1] for a variety of use cases such as photovoltaics [2] doi.org/10.3390/chemistry3020038 including singlet fission [3,4], charge transport [5], and field-effect transistors [6].
    [Show full text]