DOCSLIB.ORG

Unexpected Chemistry from the Reaction of Naphthyl and Acetylene at Combustion-Liketemperatures** Dorian S

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Unexpected Chemistry from the Reaction of Naphthyl and Acetylene at Combustion-Liketemperatures** Dorian S Angewandte Chemie International Edition:DOI:10.1002/anie.201411987 Gas-Phase Chemistry German Edition:DOI:10.1002/ange.201411987 Unexpected Chemistry from the Reaction of Naphthyl and Acetylene at Combustion-LikeTemperatures** Dorian S. N. Parker,Ralf.I.Kaiser,* Biswajit Bandyopadhyay, Oleg Kostko,Tyler P. Troy,and Musahid Ahmed* Abstract: The hydrogen abstraction/acetylene addition Thehydrogen abstraction/acetylene addition (HACA) (HACA)mechanism has long been viewed as akey route to mechanism has been proposed as akey route to PAH aromatic ring growth of polycyclic aromatic hydrocarbons formation in high-temperature environments up to 2500 K.[1,7] (PAHs) in combustion systems.However,doubt has been This fundamental route involves the sequential reaction of an drawn on the ubiquity of the mechanism by recent electronic aromatic radical such as the phenyl radical (C6H5C)with two structure calculations whichpredict that the HACA mechanism acetylene (C2H2)molecules leading eventually to the simplest [1,8] starting from the naphthyl radical preferentially forms ace- PAH, naphthalene (C10H8 ;Equations (1)–(3)). After for- naphthylene,therebyblocking cyclization to athird six- mation of naphthalene (C10H8), the HACA mechanism has membered ring. Here,byprobing the products formed in the been proposed to continue through hydrogen atom abstrac- reaction of 1- and 2-naphthyl radicals in excess acetylene under tion from the naphthalene ring leading to the 1- and/or 2- [9] combustion-like conditions with the help of photoionization naphthyl radical (C10H7C), upon which athird six-membered mass spectrometry,weprovideexperimental evidence that this aromatic ring is proposed to be formed through successive reaction produces 1- and 2-ethynylnaphthalenes (C12H8), reactions with two acetylene molecules leading to anthracene acenaphthylene (C12H8)and diethynylnaphthalenes (C14H8). and phenanthrene (C14H10). Reaction of 1-naphthyl radicals Importantly,neither phenanthrene nor anthracene (C14H10) with asingle acetylene molecule has been proposed to was found, which indicates that the HACA mechanism does synthesize acenaphthylene (C12H8)—a prospective precursor not lead to cyclization of the thirdaromatic ring as expected to nonplanar PAHs like corannulene and possibly to fullerene but rather undergoes ethynyl substitution reactions instead. (Scheme 1).[10] he gas-phase reactions of unsaturated hydrocarbons and C10H7C 127 u C2H2 26 u C12H8 152 u HC 1u 1 T ð Þþ ð Þ! ð Þþ ð ÞðÞ their radicals rapidly,exothermically,and sequentially form CH 152 u C H C 151 u HC 1u 2 hexagonal six-carbon ring structures leading to large poly- 12 8ð Þ! 12 7 ð Þþ ð ÞðÞ cyclic aromatic hydrocarbons (PAH) in sooting flames[1] of, [2] [3] [4] CH C 151 u C H 26 u C H 176 u HC 1u 3 for example,methane, benzene, and toluene. PAHs and 12 7 ð Þþ 2 2ð Þ! 14 8ð Þþ ð ÞðÞ their derivatives are considered to be toxic byproducts produced during the incomplete combustion of fossil fuels; However,recently,the molecular growth processes from these compounds are also linked to food poisoning,cancer,[5] naphthalene to anthracene and phenanthrene involving the and global warming.[6] An intimate understanding of their HACA mechanism have come under scrutiny.Comprehen- formation and growth mechanisms is therefore crucial to sive electronic structure calculations demonstrate that upon eventually eliminate the formation of PAHs in combustion formation of the 1-naphthyl radical (C10H7C), addition of processes. acetylene (C2H2)would form predominantly acenaphthylene [8a] (C12H8). Mebel et al. provide compelling evidence that the rapid cyclization of the C12H9 intermediate to form afive- [*] Dr.D.S.N.Parker,Prof. Dr.R.I.Kaiser membered ring is much faster than the addition of asecond Department of Chemistry,UniversityofHawaii at Manoa acetylene molecule leading to C14H11 followed by hydrogen Honolulu, HI 96822, (USA) loss to yield athird aromatic ring:anthracene and/or E-mail:[email protected] phenanthrene.Acomparison of these predictions with data Homepage:http://www.chem.hawaii.edu/Bil301/welcome.html from combustion flames shows that the HACA-type mech- Dr.B.Bandyopadhyay,Dr. O. Kostko, Dr.T.P.Troy,Dr. M. Ahmed ChemicalSciences Division, Lawrence Berkeley National Laboratory anism only accounts for up to 6% of phenanthrene and Berkeley,CA947200, (USA) E-mail:[email protected] [**] This work was supported by the US Department of Energy,Basic Energy Sciences (DE-FG02-03ER15411) to the University of Hawaii. The authors M.A.,B.B.,O.K.,and T.P.T., and the Advanced Light Source are supported by the Director,Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, through the Chemical Sciences Division. Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/anie.201411987. Scheme 1. Structures of acenaphthylene, corannulene, and fullerene. Angew.Chem. Int.Ed. 2015, 54,5421 –5424 2015 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim 5421 Angewandte. Communications anthracene at combustion-relevant temperatures from 1000 to 2000 K.[11] Doubts were raised earlier still on the ability of the HACA mechanism to reach the large mass of high-order PAHs such as coronene (300 u) at the experimentally observed rates,byonly adding 24 uineach step.[12] Although certainly present in combustion environments,HACAroutes have often been labeled as the most important routes to PAH formation, simply based on the observation of abundant acetylene,the knowledge that aromatic radicals play apivotal role in PAHformation, and the neatness of the empirical formula by addition of C2H2 followed by hydrogen emission. Recent work by Shukla et al. has shown that phenyl addition cyclization (PAC)forms large-mass PAHs at amuch more convincing rate than the HACA mechanism, by addition of 77 uateach step.[13] Our investigation aims to identify the product distribution for the HACA mechanism leading from the prototypical bicyclic radical, the 1- and 2-naphthyl radicals to tricyclic PAHs phenanthrene and anthracene by sequential addition to acetylene molecules.Although the HACA mechanism operates over arange of aromatic radicals and experimental conditions,our experiment investigates acentral pathway from bi- to tricyclic PAHs that is representative of the sequential two-step acetylene addition mechanism that builds an extra aromatic ring onto aPAH radical. By studying the reactions of the 1- and 2-naphthyl radicals (C10H7C)with acetylene (C2H2)under simulated combustion conditions,weprovide experimental evidence that the HACA mechanism forms firstly 1- and 2-ethynylnaphthalene (C12H8) and acenaphthylene (C12H8)and secondly diethynyl naph- thalenes (C14H8)with surprisingly no formation of the Figure 1. Mass spectra of the products of the reaction of a) 1-naphthyl previously postulated tricyclic PAHs phenanthrene and and b) 2-naphthyl radicals with acetylene in the pyrolysis reactor at apressure of 300 Torr recorded at aphoton energy of 9.0 eV. anthracene (C14H10). Theisomer-specific products of these reactions were monitored and identified by exploiting single- photon ionization by tunable vacuum ultraviolet (VUV) C14H8 (176 u) products are formed through the reaction of the [14] light. Ionized molecules were detected by reflectron time- naphthyl radical (C10H7C;127 u) with one and two acetylene of-flight mass spectrometry (ReTOF). In separate experi- molecules (C2H2 ;26u)through aseries of acetylene addition/ ments,continuous beams of 1-naphthyl and 2-naphthyl hydrogen atom eliminations [Equations (1)–(3)] with the radicals (C10H7C)were generated in situ through quantitative molecules indicated in bold detected in the present study. pyrolysis of their 1- and 2-iodonaphthalene (C10H7I) precur- Theinterpretation of the mass spectra alone provides clear sors,respectively.Each precursor was seeded in pure acety- proof that in the reaction of naphthyl radicals with acetylene, lene (C2H2)atpressures of 300 Torr and expanded into only the hydrocarbons of the molecular formulae C12H8 and aresistively heated silicon carbide tube (“pyrolytic reactor”) C14H8 are formed and no C14H10 isomers.Therefore,we at 1200 100 K.[15] Theacetylene molecules did not only act conclude that neither phenanthrene nor anthracene are Æ as aseeding gas,but also as areactant with the pyrolytically reaction products under the present experimental conditions. generated naphthyl radicals.The neutral molecular beam was It should be noted that both, phenanthrene and anthracene, then interrogated by quasicontinuous tunable vacuum ultra- have been observed and studied under identical conditions in violet (VUV) radiation in the extraction region of aReTOF the experimental apparatus in which they are fully observable mass spectrometer.The photoionized molecules were col- and identifiable.Furthermore,inthe preparation stages of the lected by amicrochannel plate detector with mass spectra experiment, the reactions were conducted at arange of being collected at intervals of 0.05 eV between 8.00 and temperatures while monitoring the mass spectra for the signal 10.00 eV (see the Supporting Information, SI). at m/z 178 (C14H10); no signal was observed at any temper- Figure 1depicts the mass spectra for the reaction of 1- ature from no heating to 1500 K. naphthyl and 2-naphthyl radicals with acetylene recorded at We now focus on the identification of each isomer by aphotoionization energy of 9.0 eV.These data provide clear analyzing the photoionization efficiency(PIE) curves,which
Load more

Recommended publications
  • Reactivity and Functionalization of Naphthalene and Anthracene Complexes of {Tpw(NO)(Pme3)}
    Reactivity and Functionalization of Naphthalene and Anthracene Complexes of {TpW(NO)(PMe3)} Laura Jessica Strausberg Baltimore, Maryland B.A., Hollins University, 2008 A Dissertation presented to the Graduate Faculty of the University of Virginia in Candidacy for the Degree of Doctor of Philosophy Department of Chemistry University of Virginia July, 2013 ii Abstract Chapter 1 introduces the organic chemistry of aromatic hydrocarbons, with attention paid to regiochemical outcomes of organic reactions. The binding of naphthalene and anthracene to metal complexes is discussed, along with organic transformations they undergo as a result of their complexation. The previous work on osmium and rhenium complexes of naphthalene from the Harman group is explored. Finally, some spectroscopic techniques for exploring the chemistry of {TpW(NO)(PMe3)} complexes of naphthalene and anthracene are introduced. Chapter 2 discusses the highly distorted allyl complexes formed from {TpW(NO)(PMe3)} and the exploration of their origin. Attempts at stereoselectively deprotonating these cationic complexes is also discussed. 2 Chapter 3 describes our study of TpW(NO)(PMe3)(3,4-η -naphthalene)’s ability to undergo a Diels-Alder reaction with N-methylmaleimide. A solvent study suggested that this reaction proceeds by a concerted mechanism. To probe the mechanism further, we synthesized a series of methylated and methoxylated naphthalene complexes and measured their rates of reaction with N-methylmaleimide compared to the parent complex. We found that 1- substitution on the naphthalene increased the rate of cycloaddition, even if the substituent was in the unbound ring, while 2-substitution slowed the reaction rate when in the bound ring. This information is consistent with a concerted mechanism, as a 2-substituted product would be less able to isomerize to form the active isomer for the cycloaddition to occur.
    [Show full text]
  • Crystal Structure of Methyl 10-(Pyridin-4-Yl)-Anthracene-9
    Z. Kristallogr. NCS 2018; 233(3): 441–443 Xiang Huang and Da-Bin Shi* Crystal structure of methyl 10-(pyridin-4-yl)- anthracene-9-carboxylate, C21H15NO2 Table 1: Data collection and handling. Crystal: Block, colorless Size: 0.30 × 0.20 × 0.10 mm Wavelength: Mo Kα radiation (0.71073 Å) µ: 0.09 mm−1 Diffractometer, scan mode: Bruker SMART, φ and ω-scans θmax, completeness: 27.6°, >99% N(hkl)measured, N(hkl)unique, Rint: 9199, 3516, 0.027 Criterion for Iobs, N(hkl)gt: Iobs > 2 σ(Iobs), 2700 N(param)refined: 218 Programs: Bruker programs [1], SHELX [2, 3] before stirring for 2 h at 65 °C. Crude 10-bromo-anthracene- 9-carboxylic acid was precipitated by adding the acetic acid solution to 800 mL of ice/water slush, followed by suc- https://doi.org/10.1515/ncrs-2017-0334 tion filtration. The residue on the filter was dissolved in Received October 31, 2017; accepted February 20, 2018; available 500 mL of a 5% aquaeus solution of K2CO3 followed by online March 6, 2018 gravity filtration to remove undissolved side products such as 9,10-dibromoanthracene. The filtrate was acidified with Abstract concentrated HCl to precipitate crude 10-bromo-anthracene- Aba a = C21H15NO2, orthorhombic, 2 (no. 41), 22.149(2) Å, 9-carboxylic acid, which was recrystallized from 100 mL b = c = V = 3 Z = 13.2899(12) Å, 10.6679(10) Å, 3140.2(5) Å , 8, ethanol to yield 5.76 g of yellow needles. R F = wR F2 = T = gt( ) 0.0418, ref( ) 0.0953, 296(2) K.
    [Show full text]
  • Construction of Novel Molecular Architectures from Anthracene Units and Acetylene Linkers*
    Pure Appl. Chem., Vol. 84, No. 4, pp. 917–929, 2012. http://dx.doi.org/10.1351/PAC-CON-11-09-07 © 2012 IUPAC, Publication date (Web): 9 February 2012 Construction of novel molecular architectures from anthracene units and acetylene linkers* Shinji Toyota‡ Department of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama 700-0005, Japan Abstract: To create novel π-conjugated compounds, we constructed various molecular archi- tectures from anthracene units and acetylene linkers. Several cyclic oligomers ranging from dimers to dodecamers were synthesized by macrocyclization of acyclic precursors with metal-catalyzed coupling reactions. The structures, dynamic behavior, and spectroscopic fea- tures were greatly influenced by the number of anthracene units and the combination of building units and linkers. Optically active and circular dichroism (CD)-active enantiomers of some chiral cyclic oligomers were resolved by chiral high-performance liquid chromato - graphy (HPLC). Conformational analysis of hexamers and higher oligomers was performed with the aid of density functional theory (DFT) calculations. Acyclic oligomers underwent reversible folding–unfolding processes via photochemical and thermal reactions. These results suggest that transannular π–π interactions between anthracene units are important fac- tors in controlling the structural and spectroscopic properties and functions of π-conjugated compounds. The scope and perspectives of this molecular design are discussed on the basis of previous studies. Keywords: aromatic compounds; alkynes; π–π interactions; stereochemistry; structure. INTRODUCTION In the chemistry of aromatic compounds, oligomeric structures consisting of simple repeating units are fascinating motifs for the creation of new compounds. The merits of this molecular design are the acces- sibility to a large number of compounds from simple building units as well as the ease of tuning elec- tronic properties by structural modifications.
    [Show full text]
  • Dissolved Organic Matter-Mediated Photodegradation of Anthracene and Pyrene in Water Siyu Zhao, Shuang Xue*, Jinming Zhang, Zhaohong Zhang & Jijun Sun
    www.nature.com/scientificreports OPEN Dissolved organic matter-mediated photodegradation of anthracene and pyrene in water Siyu Zhao, Shuang Xue*, Jinming Zhang, Zhaohong Zhang & Jijun Sun Toxicity and transformation process of polycyclic aromatic hydrocarbons (PAHs) is strongly depended on the interaction between PAHs and dissolved organic matters (DOM). In this study, a 125W high- pressure mercury lamp was used to simulate the sunlight experiment to explore the inhibition mechanism of four dissolved organic matters (SRFA, LHA, ESHA, UMRN) on the degradation of anthracene and pyrene in water environment. Results indicated that the photodegradation was the main degradation approach of PAHs, which accorded with the frst-order reaction kinetics equation. The extent of degradation of anthracene and pyrene was 36% and 24%, respectively. DOM infuence mechanism on PAHs varies depending upon its source. SRFA, LHA and ESHA inhibit the photolysis of anthracene, however, except for SRFA, the other three DOM inhibit the photolysis of pyrene. Fluorescence quenching mechanism is the main inhibiting mechanism, and the binding ability of DOM and PAHs is dominantly correlated with its inhibiting efect. FTIR spectroscopies and UV–Visible were used to analyze the main structural changes of DOM binding PAHs. Generally, the stretching vibration of N–H and C–O of polysaccharide carboxylic acid was the key to afect its binding with anthracene and C–O–C in aliphatic ring participated in the complexation of DOM and pyrene. Polycyclic aromatic hydrocarbons (PAHs) are typical persistent organic pollutants with two or more fused ben- zene rings that are widely distributed in multi-media, such as atmosphere, water, sediment, snow, and biota1–4.
    [Show full text]
  • Polycyclic Aromatic Hydrocarbons (Pahs)
    Polycyclic Aromatic Hydrocarbons (PAHs) Factsheet 4th edition Donata Lerda JRC 66955 - 2011 The mission of the JRC-IRMM is to promote a common and reliable European measurement system in support of EU policies. European Commission Joint Research Centre Institute for Reference Materials and Measurements Contact information Address: Retiewseweg 111, 2440 Geel, Belgium E-mail: [email protected] Tel.: +32 (0)14 571 826 Fax: +32 (0)14 571 783 http://irmm.jrc.ec.europa.eu/ http://www.jrc.ec.europa.eu/ Legal Notice Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use which might be made of this publication. Europe Direct is a service to help you find answers to your questions about the European Union Freephone number (*): 00 800 6 7 8 9 10 11 (*) Certain mobile telephone operators do not allow access to 00 800 numbers or these calls may be billed. A great deal of additional information on the European Union is available on the Internet. It can be accessed through the Europa server http://europa.eu/ JRC 66955 © European Union, 2011 Reproduction is authorised provided the source is acknowledged Printed in Belgium Table of contents Chemical structure of PAHs................................................................................................................................. 1 PAHs included in EU legislation.......................................................................................................................... 6 Toxicity of PAHs included in EPA and EU
    [Show full text]
  • Anthracene Related to Carcinogenicity1
    [CANCER RESEARCH 29,506—509,March1969] Molecular Site of Substituents of Benz(a)anthracene Related to Carcinogenicity1 JohnPatakiandCharlesHuggins The Ben May Laboratory for Cancer Research, The University ofChicago, Chicago, Illinois 60637 SUMMARY The tumor-producing effect of dibenz(a,h)anthracene led Cook (5) to undertake experiments showing that 9-isopropyl Benz(a)anthracene did not induce tumors in rats, but its BA is a (weak) carcinogenand Fieseret aL (9) synthesizedthe derivatives were highly and equally carcinogenic when they stronger cancer-producing substances 7-methyl-BA and possessed two or three methyl groups in any combination at 7,8-DMBA. Considerably later it was found that 7,12-DMBA the following special sites: positions 6, 7, 8, or 12. Derivatives (1), 7,8,12-TMBA (1), and 6,7,8-TMBA (21) are very powerful of benz(a)anthracene with pairs of methyl groups at sites 1 carcinogens. It was evident that substitution of BA at positions and 12 or 3 and 9 were not carcinogenic. 7,12-Dimethylbenz 7 and 8 to form cholanthrene or 7,8-DMBA was more effective (a)anthracene and 7,8,12-trimethylbenz(a)anthracene are in promoting carcinogenic potency than substitution of BA at equivalent in their ability to elicit neoplasms in rats and far positions 8 and 9 was, irrespective of whether a new ring was exceed 3-methylcholanthrene and benzo(a)pyrene in this formed or the substituents remained as alkyl groups. regard. MATERIALSANDMEThODS INTRODUCTION Chemicals. Of 26 compounds which were tested, four were In this paper it will be demonstrated that the addition of new.
    [Show full text]
  • COMMUNICATION HACA’S Heritage: a Free Radical Pathway to Phenanthrene in Circumstellar Envelopes of Asymptotic Giant Branch Stars Tao Yang,[A] Ralf I
    COMMUNICATION HACA’s Heritage: A Free Radical Pathway to Phenanthrene in Circumstellar Envelopes of Asymptotic Giant Branch Stars Tao Yang,[a] Ralf I. Kaiser,[a]* Tyler P. Troy,[b] Bo Xu,[b] Oleg Kostko,[b] Musahid Ahmed,[b]* Alexander M. Mebel,[c]* Marsel V. Zagidullin[d] and Valeriy N. Azyazov[d] Abstract: The Hydrogen-Abstraction/Acetylene-Addition (HACA) mechanism has been central for the last decades in attempting to rationalize the formation of polycyclic aromatic hydrocarbons (PAHs) as detected in carbonaceous meteorites such as in Murchison. Nevertheless, the basic reaction mechanisms leading to the formation of even the simplest tricyclic PAHs like anthracene and phenanthrene are still elusive. Here, by exploring the previously unknown chemistry of the ortho-biphenylyl radical with acetylene, we deliver compelling evidence on the efficient synthesis of phenanthrene in carbon-rich circumstellar environments. However, the lack of formation of the anthracene isomer implies that HACA alone cannot be responsible for the formation of PAHs in extreme environments. Considering the Figure 1. Structures of biphenyl, naphthalene, acenaphthylene, overall picture, alternative pathways such as vinylacetylene- anthracene, and phenanthrene. mediated reactions are required to play a crucial role in the synthesis of complex PAHs in circumstellar envelopes of dying systems.[17-20] Based on electronic structure calculations[19, 21-24] and carbon-rich stars. kinetic modeling,[16, 25-29] HACA has been suggested to involve a repetitive sequence of atomic
    [Show full text]
  • A COMPARATIVE STUDY of TWO STAGE ELECTROCHEMICAL OXIDATION of ANTHRACENE, NAPHTHALENE and BENZENE USING Ce4+/Ce3+ REDOX SYSTEM
    Bulletin 0/ Electrochemistry 15 (7-8) Jul y-AugUSl 1999, pp 293-297 0256-1654/99/$ 3-50 © 19QQ CEeR [ A COMPARATIVE STUDY OF TWO STAGE ELECTROCHEMICAL OXIDATION OF ANTHRACENE, NAPHTHALENE AND BENZENE USING Ce4+/Ce3+ REDOX SYSTEM T VUAYARARATIII, R KANAKAM SRINIVASAN AND M NoF.L Central Ekctrodll'lllical Research Institute, Karaikudi 630000_ INDIA Two st.a~e electrochemical oxidation of anthracene, naphthalene and henzene were carried out to evaluate the relative ease of oxidation. Electrochemically generated Ce4+ species from sulphuric acid as well as methane sulphonic acid were employed to study the chemical oxidation step. The chemical step was carried out Iwth in the absence and in presence of added solvents such as dichloromethane and dichloroethane. 2.0 M methane sulphonic acid was found to be the medium of choice for the efficient oxidation of all the three compounds. Relatively higher reaction temperatures were reC(uind for the oxidation of naphthalene and henzene when compared to anthracene. In the case of henzene excess reactant itst'lf had to he used as a solvent. The reaction time was found to he considerably hi~her for henzene when compared to the other two compounds. Under optimum conditinns maximum yidd elf anthraquinune, naphthaquinone and benzoquinone were found to be 97%, 93% and 45% respectively. Keywords: Redo" system, electrochemical oxidation, polycylindro carbons INTRODUCTION present work wht'Tever possible efforts werc made to improve the yield and efficiency. 4 Ce + salts are known to he an efficient oxidising ag,'nt for EXI'ERIMENTAL the. oxidation of polycyclic hydrocarbons like anthracene and naphthalene [I-51.
    [Show full text]
  • Triplet States and Triplet Excitons in Chemically Mixed Crystals
    o (1995 ΛCA PHYSICA POLONICA A o 3 IE SAES A IE ECIOS I CEMICAY MIE CYSAS O ACIIE WI AACEE O MOAWSKI A OCOOW Isiue o ysics ois Acaemy o Sceces A oików 3/ - Wasawa oa (Received May 9, 1995) eicae o oessos Kyso igoń óe W oee a isław uiewic o e occasio o ei 7 iay? Seca a emoa caaceisics a ei emeaue eeece o e og-ie (osoescece a eaye uoescece emissioii o cemicay mie cysas o aciie II (os wi aacee (gues wee suie ue coiios o aious seca esouios a iee moes o eciaio e eegy o - asiios o ecio a a o a saes ae ee eemie a e aue a eegy sceme o e ie saes o cysas ae ee esaise e cke aageme o os moecues io wo iee ais i e cysa sucue o aciie II is eeae i e eegeic "oue" sucue o e a saes o o . e saow a e ee as (o aciie a o aacee oigi e- seciey Migaio o ie eciaioii eegy i ese cemicay mie cysas is cooe eomiay y e ie-ie aiiaio o ecios (eie eeogeeous o kogeeous amos i e woe em- eaue age e omaio o ie ecimes o aciie was eiiey ue ou ACS umes 317Ks 335q 7135+- 1 Ioucio Some ime ago e wo-comoe ogaic soi souios wi susiu- ioa isoe ie isooicay o cemicay mie moecua cysas seeme o e ey aacie as e moe sysems o igy isoee sysems (eg moecu- a gasses oymes a iquis [1] I as ue ou owee a i cemicay Sumie o iiaio o e Isiue o ysica a eoeica Cemisy ecica Uiesiy o Wocław Wocław oa (9 470 O.
    [Show full text]
  • Optimal Conditions for Treatment of Contaminated Waters with Anthracene by Fenton Processes in Close System Reactor Faiq F
    ISSN: 0974-2115 www.jchps.com Journal of Chemical and Pharmaceutical Science Optimal conditions for treatment of contaminated waters with anthracene by Fenton processes in close system reactor Faiq F. Karam*1 Falah H. Hussein2 Sadiq J. Baqir3 Ayad F. Alkaim4 *1 Chemistry Department, College of Science, Al-Qadisiyah University, Diwaniya 58002, Iraq 2 College of Pharmacy, Babylon University, Hilla 51002, Iraq 3 Chemistry Department, College of Science, Babylon University, Hilla 51002, Iraq 4 Chemistry Department, College of Science for women, Babylon University, Hilla 51002, Iraq *Corresponding author: E-mail: [email protected] Abstract Advanced Oxidation Processes such as Fenton, Photo-Fenton and Electro-Fenton have been applied effectively to remove the organic pollutants from the water and soil previously. Fenton reaction principle is based on the addition of hydrogen peroxide to the contaminated water or waste water in the presence ferrous salts as a catalyst to generate hydroxyl radicals. In this study, the effect of different parameters on the degradation by Fenton processes have been reported such as concentration of Anthracene, amount of FeSO4, pH value, temperature and hydrogen peroxide amount. The results indicate that the perfect conditions for degradation of Anthracene by Fenton -1 process were: Anthracene concentration 16 mg l , mass of FeSO4 = 120mg, pH of solution =4, temperature of solution 50 ₒC and Concentration of hydrogen peroxide = 150 mg l-1. KEYWORD: Fenton, pollution with PAHs, degradation of Anthracene, water treatment. 1. INTRODUCTION Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous environmental contaminants that mainly originate by incomplete combustion of organic matter. Some of these have mutagenic and carcinogenic potentials(Paula 2009).
    [Show full text]
  • Liquid-Phase Oxidation of Anthracene in Acetic Acid with an Oxygen/Nitric Acid System
    J. Chem. Tech. Biotechnol. 1990, 49, 5544 Liquid-phase Oxidation of Anthracene in Acetic Acid with an Oxygen/Nitric Acid System C. K. Das & N. S. Das Central Fuel Research Institute, PO FRI, District Dhanbad, Bihar PIN 828 108, India (Received 18 September 1989; accepted 24 November 1989) ABSTRACT Oxidation of anthracene in acetic acid by the oxygenlnitric acid system has been studied and an attempt has been made to ascertain a practical limit of the amount of solvent keeping the commercial prospects in view. The effects of other reaction parameters such as flow rate, amount of nitric acid and water, residence time, etc., have been investigated. While opting for a solvent1 substrate ratio of 10, the optimum conversion of anthracene to anthraquinone fiee from nitro-compounds has been found to be 91 with purity of 98.7%, acceptable to dye-stuff industries. Key words: anthracene, anthraquinone, oxidation in liquid phase, oxygen, nitric acid. 1 INTRODUCTION Oxidation of anthracene in the liquid phase by nitric acid is a thermodynamically favourable reaction. Several attempts have been made earlier to develop the process, using this comparatively low-priced yet strongly oxidising agent to explore commercial viabilities.'" Oxidation with nitric acid alone is a stoichiometric reaction. Very dilute acid at lower temperature requires a long induction period, while with the use of strong nitric acid, the product purity may be affected, due to side reactions, such as nitration, which may also affect the overall economy of the process.'S2 However, nitric acid as co-oxidant with airloxygen has been found to be useful in oxidising anthra~ene.'.~.~The concentration of the acid requires proper adjustment to suppress the formation of undesired by-products and accordingly, an optimum limit has been suggested previously by the present authors.* In spite ofthe fact that the synthesis involves mild reaction conditions and simple techniques, thus 55 J.
    [Show full text]
  • DNA Interactions and Photocleavage by Anthracene, Acridine, and Carbocyanine-Based Chromophores
    Georgia State University ScholarWorks @ Georgia State University Chemistry Dissertations Department of Chemistry Fall 9-23-2013 DNA Interactions and Photocleavage by Anthracene, Acridine, and Carbocyanine-Based Chromophores Carla Mapp Follow this and additional works at: https://scholarworks.gsu.edu/chemistry_diss Recommended Citation Mapp, Carla, "DNA Interactions and Photocleavage by Anthracene, Acridine, and Carbocyanine-Based Chromophores." Dissertation, Georgia State University, 2013. https://scholarworks.gsu.edu/chemistry_diss/82 This Dissertation is brought to you for free and open access by the Department of Chemistry at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Chemistry Dissertations by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]. DNA INTERACTIONS AND PHOTOCLEAVAGE BY ANTHRACENE, ACRIDINE, AND CARBOCYANINE-BASED CHROMOPHORES by CARLA TERRY MAPP Under the Direction of Dr. Kathryn B. Grant ABSTRACT The interaction of small molecules with DNA has been extensively studied and has produced a large catalogue of molecules that non-covalently bind to DNA though groove binding, intercalation, electrostatics, or a combination of these binding modes. Anthracene, acridine, and carbocyanine-based chromophores have been examined for their DNA binding properties and photo-reactivities. Their planar aromatic structures make them ideal chromophores that can be used to probe DNA structural interactions and binding patterns. We have studied DNA binding and photocleavgage properties of a bisacridine chromophore joined by a 2,6-bis(aminomethyl)pyridine copper-binding linker (Chapter II), a series of 9-aminomethyl anthracene chromophores (Chapters III and IV), both under conditions of high and low ionic strength, as well as a series of pentamethine linked symmetrical carbocyanine dyes (Chapter V).
    [Show full text]