- One-Pot Synthesis of Tetraphene and Construction of Expanded Conjugated Aromatics
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Acene derivatives as a class of polycyclic aromatic hydrocarbons have attracted considerable interest because of their outstanding semiconductor properties. We developed a one-pot synthesis for fully conjugated tetraphene via a sequence of propargyl-allenyl isomerization, phosphine addition, intramolecular Wittig reactions, and Diels-Alder cyclization reactions. The derivative-conjugated aromatic compounds including carbazole or triphenylamine have been constructed via Pd-catalyzed coupling reaction with dibromotetraphene. These compounds show superior photophysical and electrochemical properties, which make them possible candidates for optoelectronic conjugated materials.
- Wang, Jianbo,Yao, Jinzhong,Wang, Hailong,Chen, Hao,Dong, Jingcheng,Zhou, Hongwei
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Read Online
- Industrial production method of benzo [a] anthracene
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The invention discloses an industrial production method of benzo [a] anthracene, which belongs to the technical field of organic synthesis, and comprises the following steps of carrying out lithium substitution on 2-bromonaphthalene through 2, 2, 6, 6-tetramethylpiperidine lithium, and carrying out boron esterification and acidification through triisopropyl borate to obtain 2-bromo-3-naphthaleneboronic acid, carrying out Suzuki reaction on 2-bromo-3-naphthaleneboronic acid and iodobenzene to prepare 2-bromo-3-phenyl naphthalene, carrying out lithium substitution on 2-bromo-3-phenyl naphthalene and n-butyllithium, and preparing 2-formyl-3-phenyl naphthalene through DMF, carrying out Witting reaction on 2-formyl-3-phenyl naphthalene, chloromethyl ether triphenylphosphine salt and sodium tert-butoxide to prepare 2-methoxyvinyl-3-phenyl naphthalene, and enabling 2-methoxyvinyl-3-phenyl naphthalene to be subjected to ring closing through methanesulfonic acid, and preparing benzo [a] anthracene. Compared with an existing benzo [a] anthracene synthesis method, raw materials are cheap and easy to obtain, operation is easy, discharge of three wastes is small, preparation is environmentally friendly, and industrial production is facilitated.
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- Cascade reaction for the synthesis of polycyclic aromatic hydrocarbons via transient directing group strategy
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A Pd(II)-catalyzed cascade synthesis of diverse polycyclic aromatic hydrocarbons via transient directing group strategy has been developed, involving the consecutive arylation, cyclization and aromatization. The efficiency and practicality were demonstrated by wide substrate range, concise synthetic pathway and mild reaction conditions. The subsequent transformations of the benz[a]anthracene core accessed natural bioactive PAH molecules.
- Wang, Ziqi,Dong, Wendan,Sun, Bing,Yu, Qinqin,Zhang, Fang-Lin
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supporting information
p. 4031 - 4041
(2019/07/03)
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- Reactivity Variation of Tetracyanoethylene and 4-Phenyl-1,2,4-Triazoline-3,5-Dione in Cycloaddition Reactions in Solutions
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The reasons for the very high reactivity and variability of reactivity of two dienophiles, tetracyanoethylene (1) and 4-phenyl-1,2,4-triazoline-3,5-dione (2), in the Diels–Alder reactions were considered. The data on the rate of reactions with anthracene (3), benzanthracene (4) and dibenzanthracene (5) in 14 solvents over a range of temperatures and high pressures, data on the change in the enthalpy of solvation of reagents, transition state, and adducts in the forward and backward reactions, and the enthalpies of these reactions in solution were obtained. Strong π-acceptor dienophile 1 has sharply reduced reactivity in reactions in π-donor aromatic solvents. It was observed that the π-acceptor properties of dienophile 1 disappear upon passage to the transition state and adduct. Large solvent effects on the reaction rate can be predicted for all types of reactions involving tetracyanoethylene. Very high reactivity of dienophiles 1 and, especially, 2 can be useful to catch such carcinogenic impurities such as 3–5 and neutralize them by transformation into less dangerous adducts.
- Kiselev, Vladimir D.,Kornilov, Dmitry A.,Anikin, Oleg V.,Shulyatiev, Alexey A.,Konovalov, Alexander I.
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- Facile Synthesis of Polycyclic Aromatic Hydrocarbons: Br?nsted Acid Catalyzed Dehydrative Cycloaromatization of Carbonyl Compounds in 1,1,1,3,3,3-Hexafluoropropan-2-ol
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The cycloaromatization of aromatic aldehydes and ketones was readily achieved by using a Br?nsted acid catalyst in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP). In the presence of a catalytic amount of trifluoromethanesulfonic acid, biaryl-2-ylacetaldehydes and 2-benzylbenzaldehydes underwent sequential intramolecular cationic cyclization and dehydration to afford phenacenes and acenes, respectively. Furthermore, biaryl-2-ylacetaldehydes bearing a cyclopentene moiety at the α-position underwent unprecedented cycloaromatization including ring expansion to afford triphenylenes. HFIP effectively promoted the cyclizations by suppressing side reactions presumably as a result of stabilization of the cationic intermediates.
- Fujita, Takeshi,Takahashi, Ikko,Hayashi, Masaki,Wang, Jingchen,Fuchibe, Kohei,Ichikawa, Junji
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supporting information
p. 262 - 265
(2017/01/24)
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- Ultrasound assisted Bradsher reaction in aqueous and non-aqueous media: First use of ultrasounds in electrophilic aromatic cyclisation leading to polyacenes
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The present work describes the first use of ultrasounds in the Bradsher cyclisation of activated and non-activated ortho-formyl diarylmethanes. This reaction is also the first example of electrophilic, aromatic cyclisation assisted by ultrasounds which leads to pure polycyclic, fused aromatic hydrocarbons containing 3 and 4 fused rings in excellent yields. The reaction proceeds not only in aqueous but also in non-aqueous media at milder conditions (room temperature) and in much shorter reaction times than in conventional protocols.
- Kowalska, Emilia,Ba?czewski, Piotr
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p. 743 - 753
(2016/07/25)
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- Products of the Propargyl Self-Reaction at High Temperatures Investigated by IR/UV Ion Dip Spectroscopy
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The propargyl radical is considered to be of key importance in the formation of the first aromatic ring in combustion processes. Here we study the bimolecular (self-) reactions of propargyl in a high-temperature pyrolysis flow reactor. The aromatic reaction products are identified by IR/UV ion dip spectroscopy, using the free electron laser FELIX as mid-infrared source. This technique combines mass selectivity with structural sensitivity. We identified several aromatic reaction products based on their infrared spectra, among them benzene, naphthalene, phenanthrene, indene, biphenyl, and surprisingly a number of aromatic compounds with acetylenic (ethynyl) side chains. The observation of benzene confirms that propargyl is involved in the formation of the first aromatic ring. The observation of compounds with acetylenic side chains shows that, in addition to a propargyl- and phenyl-based mechanism, the HACA (hydrogen abstraction C2H2 addition) mechanism of polycyclic aromatic hydrocarbons formation is present, although no acetylene was used as a reactant. On the basis of the experimental results we suggest a mechanism that connects the two pathways.
- Constantinidis,Hirsch,Fischer,Dey,Rijs
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p. 181 - 191
(2017/06/07)
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- Microwave flash pyrolysis: C9h8 interconversions and dimerisations
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The pyrolysis of 2-ethynyltoluene, indene, fluorene, and related compounds has been studied by sealed tube microwave flash pyrolysis (MFP), in concert with modelling of putative mechanistic pathways by density functional theory (DFT) computations. In the MFP technique, samples are admixed with graphite and subjected to intense microwave power (150-300 W) in a quartz reaction tube under a nitrogen atmosphere. The MFP reaction of 2-ethynyltoluene gave mostly indene, the product of a Roger Brown rearrangement (1,2-H shift to a vinylidene) followed by insertion. An additional product was chrysene, the likely result of hydrogen atom loss from indene followed by dimerisation. The intermediacy of dimeric bi-indene structures was supported by pyrolysis of bi-indene and by computational models. Benzo[a]anthracene and benzo[c]phenanthrene are minor products in these reactions. These are shown to arise from pyrolysis of chrysene under the same MFP conditions. MFP reaction of fluorene gave primarily bi-fluorene, bifluorenylidene, and dibenzochrysene, the latter derived from a known Stone-Wales rearrangement.
- Ajaz, Aida,Voukides, Alicia C.,Cahill, Katharine J.,Thamatam, Rajesh,Skraba-Joiner, Sarah L.,Johnson, Richard P.
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p. 1301 - 1308
(2014/11/07)
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- Indium-catalyzed construction of polycyclic aromatic hydrocarbon skeletons via dehydration
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Polycyclic aromatic compounds can be synthesized from 2-benzylic- or 2-allylbenzaldehydes using a catalytic amount of In(III) or Re(I) complexes. By using this method, polycyclic aza-aromatic compounds can also be prepared efficiently. In these reactions, only water is formed as a side product.
- Kuninobu, Yoichiro,Tatsuzaki, Tomohiro,Matsuki, Takashi,Takai, Kazuhiko
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experimental part
p. 7005 - 7009
(2011/10/09)
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- Synthesis of uniformly 13C-labeled polycyclic aromatic hydrocarbons
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Convergent synthetic pathways were devised for efficient synthesis of a series of uniformly 13C labeled polycyclic aromatic hydrocarbons de novo from U-13C-benzene and other simple commercially-available 13C-starting compounds. All target products were obtained in excellent yields, including the alternant PAH U-13C-naphthalene, U-13C-phenanthrene, U-13C-anthracene, U- 13C-benz[a]anthracene, U-13C-pyrene and the nonalternant PAH U-13C-fluoranthene.
- Zhang, Zhenfa,Sangaiah, Ramiah,Gold, Avram,Ball, Louise M.
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p. 5431 - 5435
(2011/09/14)
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- Role of temperature and hydrochloric acid on the formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons during combustion of paraffin powder, polymers, and newspaper
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Formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were determined using a laboratory-scale incinerator when combusting materials at different temperatures, different concentrations of hydrochloric acid (HCl), and when combusting various types of polymers/newspaper. Polychlorobenzenes (PCBz), polychlorophenols (PCPhs), polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and their toxic equivalency (TEQ) and PAHs were highlighted and reported. Our results imply maximum formation of chlorinated hydrocarbons at 400°C in the following order; PCBz≥PCPhs?PCDFs>PCDDs>TEQ on a parts-per-billion level. Similarly, a maximum concentration of chlorinated hydrocarbons was noticed with an HCl concentration at 1000 ppm with the presence of paraffin powder in the following order; PAHs>PCBz≥PCPhs?PCDFs>PCDDs>TEQ an a parts-per-billion level. PAHs were not measured at different temperatures. Elevated PAHs were noticed with different HCl concentrations and paraffin powder combustion (range: 27-32 μg/g). While, different polymers and newspaper combusted, nylon and acrylonitrile butadiene styrene (ABS) produced the maximum hydrogen cyanide (HCN) concentration, concentrations of PCDD/FS, dioxin-like polychlorinated biphenyls (DL-PCBs), and TEQ were in a decreasing order: polyvinylchloride (PVC)newspaperpolyethyleneterephthalate (PET) polyethylene (PE) polypropylene (PP) ABS = blank. Precursors of PCBs were in a decreasing order: PPnylonPEnewspaperABSPVCblankPET. Precursors of PCDD/Fs were in a decreasing order: newspaper PP= nylonPEABSPVC= blankPET. BTX formation was in a decreasing order; PEnylonnewspaperABSPP. PAHs formation were elevated with parts-per-million levels in the decreasing order of PPnylonPE newspaperblankABS PETPVC.
- Takasuga, Takumi,Umetsu, Norihito,Makino, Tetsuya,Tsubota, Katsuya,Sajwan, Kenneth S.,Kumar, Kurunthachalam Senthil
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- Emission factors and importance of PCDD/Fs, PCBs, PCNs, PAHs and PM 10 from the domestic burning of coal and wood in the U.K.
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This paper presents emission factors (EFs) derived for a range of persistent organic pollutants (POPs) when coal and wood were subject to controlled burning experiments, designed to simulate domestic burning for space heating. A wide range of POPs were emitted, with emissions from coal being higher than those from wood. Highest EFs were obtained for particulate matter, PM10, (～ 10 g/kg fuel) and polycyclic aromatic hydrocarbons (～ 100 mg/ kg fuel for ΣPAHs). For chlorinated compounds, EFs were highest for polychlorinated biphenyls (PCBs), with polychlorinated naphthalenes (PCNs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) being less abundant. EFs were on the order of 1000 ng/kg fuel for ΣPCBs, 100s ng/ kg fuel for ΣPCNs and 100 ng/kg fuel for ΣPCDD/Fs. The study confirmed that mono- to trichlorinated dibenzofurans, Cl1,2,3DFs, were strong indicators of low temperature combustion processes, such as the domestic burning of coal and wood. It is concluded that numerous PCB and PCN congeners are routinely formed during the combustion of solid fuels. However, their combined emissions from the domestic burning of coal and wood would contribute only a few percent to annual U.K. emission estimates. Emissions of PAHs and PM 10 were major contributors to U.K. national emission inventories. Major emissions were found from the domestic burning for Cl1,2,3DFs, while the contribution of PCDD/F-ΣTEQ to total U.K. emissions was minor.
- Lee, Robert G. M.,Coleman, Peter,Jones, Joanne L.,Jones, Kevin C.,Lohmann, Rainer
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p. 1436 - 1447
(2007/10/03)
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- Experimental study on the removal of PAHs using in-duct activated carbon injection
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This paper presents the incineration tests of municipal solid waste (MSW) in a fluidized bed and the adsorption of activated carbon (AC) on polycyclic aromatic hydrocarbons (PAHs). An extraction and high performance liquid chromatography (HPLC) technique was used to analyze the concentrations of the 16 US EPA specified PAHs contained in raw MSW, flue gas, fly ash, and bottom ash. The aim of this work was to decide the influence of AC on the distribution of PAHs during the incineration of MSW. Experimental researches show that there were a few PAHs in MSW and bottom ash. With the increase of AC feeding rate, the concentrations of three- to six-ring PAHs in fly ash increased, and the concentration of two-ring PAH decreased. The total-PAHs in flue gas were dominated by three-, and four-ring PAHs, but a few two-, five-ring PAHs and no six-ring PAHs were found. PAHs could be removed effectively from flue gas by using in-duct AC injection and the removal efficiencies of PAHs were about 76-91%. In addition, the total toxic equivalent (TEQ) concentrations of PAH in raw MSW, bottom ash, fly ash, and flue gas were 1.24 mg TEQ kg-1, 0.25 mg TEQ kg-1, 6.89-9.67 mg TEQ kg-1, and 0.36-1.50 μg TEQ N m-3, respectively.
- Zhou, Hong-Cang,Zhong, Zhao-Ping,Jin, Bao-Sheng,Huang, Ya-Ji,Xiao, Rui
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p. 861 - 869
(2007/10/03)
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- Emission factors for carbonaceous particles and polycyclic aromatic hydrocarbons from residential coal combustion in China
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Emission factors of carbonaceous particles, including black carbon (BC) and organic carbon (OC), and polycyclic aromatic hydrocarbons (PAHs) were determined for five coals, which ranged in maturity from sub-bituminous to anthracite. They were burned in the form of honeycomb briquettes in a residential coalstove, one of the most common fuel/stove combinations in China. Smoke samples were taken through dilution sampling equipment, with a high volume sampler that could simultaneously collect emissions in both particulate and gaseous phases, and a cascade impactor that could segregate particles into six fractions. Particulate BC and OC were analyzed by a thermal-optical method, and PAHs in emissions of both phases were analyzed by GC-MS. Burning of bituminous coals produced the highest emission factors of particulate matter (12.91 g/kg), BC (0.28 g/kg), OC (7.82 g/kg), and 20 PAHs (210.6 mg/kg) on the basis of burned dry ash-free (daf) coal, while the anthracite honeycomb-briquette was the cleanest household coal fuel. The size-segregated results show that more than 94% of the particles were submicron, and calculated mass median aerodynamic diameters (MMAD) of all particles were under 0.3 μm. Based on the coal consumption in the residential sector of China, 290.24 Gg (gigagrams) of particulate matter, 5.36 Gg of BC, 170.33 Gg of OC, and 4.72 Gg of 20 PAHs mass were emitted annually from household honeycomb-briquette burning during 2000. Anthracite coal should be selected preferentially and more advanced burning conditions should be applied in domestic combustion, from the viewpoint of both climate change and adverse health effects.
- Chen, Yingjun,Sheng, Guoying,Bi, Xinhui,Feng, Yanli,Mai, Bixian,Fu, Jiamo
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p. 1861 - 1867
(2008/12/21)
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- Complete study of the pyrolysis and gasification of scrap tires in a pilot plant reactor
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The pyrolysis and gasification of tires was investigated in a pilot plant reactor provided with a system for condensation of semivolatile matter. The study comprised experiments at 450°, 750°, and 1000°C both in nitrogen and 10% oxygen atmospheres. In the gas phase, only methane and benzene yields increased with temperature until 1000°C. In the liquids, the main components were styrene, limonene, and isoprene. The solid fraction (including soot) increased with temperature. Zinc content of the char decreased with increasing temperature. Analysis of the surface area of the solids showed that the area was similar in all cases to that of a commercial carbon black. The higher surface of the soot with respect to the chars was observed. The results coincided with published findings, i.e., kinetic severity function values would produce 0.2% of methane at 450°C and 4.5% at 750°-1000°C.
- Conesa, Juan A.,Martin-Gullon,Font,Jauhiainen
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p. 3189 - 3194
(2008/12/21)
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- Relationship between pressure fluctuations and generation of organic pollutants with different particle size distributions in a fluidized bed incinerator
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The hydrodynamic behaviors of fluidization perhaps significantly influence the uniformity of fluidization in fluidized bed incinerator. Good uniformity of fluidization expressed the air across uniformly through the bed and the particles being distributed well in the fluid stream. The aggregates, flocs and channels of particles do not happen during fluidization. The Good uniformity will maintain high heat and mass distribution to improve reaction efficiency. These parameters include the height of static bed, gas velocity, mixing and distribution of bed particle, which have rarely been studied in previous investigations. Consequently, this study examines how the hydrodynamic parameters affect the generation of organic pollutants (BTEXs and PAHs) during incineration. The statistical and power spectral analysis of the measured pressure fluctuation during incineration are used to elucidate the relationship between behaviors of fluidization and generation of pollutants during incineration. Experimental results show the organic concentration does not increase with uniformity of fluidization decreasing. The reason may be the explosion of the gas and the consequent thermal shock destroy the coalescent bubbles to form small bubbles again and enhance the efficiency of transfer of oxygen to increase combustion efficiency. Additionally, the mean amplitude and fluidized index of pressure fluctuation similarly vary with the concentration of organic pollutants. These two indices can be used to assess the efficiency of combustion. The four particle size distributions could be divided into two groups by statistical analysis. The Gaussian and narrow distributions belong to one group and the binary and flat the other. The organic concentration of the Gaussian and narrow distributions are lower than that of the other distributions. Consequently, the bed materials should maintain narrow or Gaussian distributions to maintain a good combustion efficiency during incineration.
- Lin, Chiou-Liang,Wey, Ming-Yen,Cheng, Han-Tsung
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p. 911 - 922
(2007/10/03)
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- Flash vacuum pyrolysis of 1,6-diphenyl-1,5-hexadien-3-ynes: Tandem diaryldienyne cyclizations to form chrysene
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Flash vacuum pyrolysis of 1,6-diphenyl-1,5-hexadien-3-yne at 1000°C and its bromo derivative at 800°C yielded chrysene as the major product through tandem diaryldienyne cyclizations.
- Sonoda, Motohiro,Itahashi, Kayo,Tobe, Yoshito
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p. 5269 - 5272
(2007/10/03)
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- Characterization of emissions during the heating of tyre contaminated scrap
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In order to characterize the compounds (type and quantities) emitted during melting of organic contaminated scrap and to investigate the mechanism of their formation, an experimental set-up has been designed and built to study precisely the influence of temperature and gas atmosphere in the conditions of an electric arc furnace. These experiments lead to the determination of mass balances (C, H, O, S) and to the quantification of unburnt compounds (tars, carbon monoxide, volatile organic compounds (VOCs), benzene, toluene, ethylbenzene and xylenes (BTEX), polyaromatic compounds (PAHs)). Degradation conditions (gas atmosphere and temperature) corresponding to different areas in the electric furnace have also been investigated. Such experiments lead to a better understanding of degradation mechanisms; this interpretation is not possible from investigations performed in an industrial furnace since there are many uncontrolled parameters (large dispersion of the results).
- Arion,Baronnet,Lartiges,Birat
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p. 853 - 859
(2007/10/03)
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- Removal of dioxins and related aromatic hydrocarbons from flue gas streams by adsorption and catalytic destruction
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The dioxin removing capacity of the shell dedioxin system (SDDS a - Ti/V oxidative type catalyst) has been tested using the Umefa lab-scale incinerator over the temperature range 100 -230°C and at space velocities of 8000 and 40,000 h-1. Other analogous organic compounds, such as PCBs, PAHs, chlorobenzenes and chlorophenols have also been investigated. Results show a high degree of dioxin removal already at 100°C (82%), which occurs mainly by adsorption. When the temperature is raised a transition towards destruction is seen and at 150°C, gas hour space velocity (GHSV) 8000 and at 230°C, GHSV 40,000 virtually all removal is by destruction. High PCDD/F destruction efficiencies are reported (> 99.9%, based on I-TEQ); the other dioxin-related species and PAHs are also removed and destroyed to a significant extent. The SDDS has proved to be an effective means of destroying organic compounds in the gas phase, particularly dioxins, at temperatures as low as 150°C.
- Liljelind, Per,Unsworth, John,Maaskant, Onno,Marklund, Stellan
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p. 615 - 623
(2007/10/03)
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- Aromatic hydrocarbon growth from indene
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Aromatic hydrocarbon growth from indene (C9H8), which contains the five-membered ring cyclopentadienyl moiety, was investigated experimentally in a 4 s flow reactor over a temperature range 650-850°C. Major products observed were three C18H12 isomers (chrysene, benz[a]anthracene and benzo[c]phenanthrene), two C17H12 isomers (benzo[a]fluorene and benzo[b]fluorene), and two C10H8 isomers (naphthalene and benzofulvene). Reaction pathways to these products are proposed. Indenyl radical addition to indene produces a resonance-stabilized radical intermediate which further reacts by one of two routes. Rearrangement by intramolecular addition produces a bridged structure that leads to the formation of C17H12 and C10H8 products. Alternatively, β scission produces biindenyl, which leads to the formation of C18H12 products by a ring condensation mechanism analogous to that proposed for cyclopentadiene-to-naphthalene conversion. Temperature dependencies of both the partitioning between these two routes and the product isomer distributions are consistent with thermochemical modeling using semi-empirical molecular orbital methods. The results further illustrate the role of resonance-stabilized radical rearrangement in aromatic growth and condensation of systems with cyclopentadienyl moieties.
- Lu, Mingming,Mulholland, James A.
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p. 625 - 633
(2007/10/03)
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- Fine particle and gaseous emission rates from residential wood combustion
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Residential wood combustion emissions were analyzed to determine emission rates and to develop chemical emissions profiles that represent the appliances and woods typically used in wood-burning-communities. Over 350 elements, inorganic compounds, and organic compounds were quantified. A range of 4-9 g/kg dry fuel of particulate matter(a dilution stack sampler equipped with a 2.5-μm particle selective cyclone. Emissions were diluted 20-70 times, cooled to ambient temperature, and allowed 80 s for condensation prior to collection. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Fine particle and se mivolatile organic compounds were collected on filter/PUF/XAD/PUF cartridges. Inorganic samples and mass were collected on Teflon and quartz filters. Volatile organic carbon compounds were trapped with Tenax (C8- C20), canister (C2-C12), and 2,4-dinitrophenylhydrazine impregnated cartridges (carbonyl compounds). Analysis of particle and semivolatile organic species was conducted by gas chromatography/mass spectrometry. Teflon filters were analyzed for mass by gravimetry, trace elements were analyzed by X-ray fluorescence and ammonium was analyzed by automated colorimetry. Quartz filters were analyzed for organic and elemental carbon by thermal/optical reflectance, and forts were analyzed by ion chromatography. Select quartz filters were analyzed by accelerator mass spectrometry for carbon-12 and carbon-14 abundance. Canister and Tenax samples were analyzed by gas chromatography with a flame ionization detector, and carbonyl compounds were analyzed by high-performance liquid chromatography. Residential wood combustion emissions were analyzed to determine emission rates and to develop chemical emissions profiles that represent the appliances and woods typically used in wood-burning communities. Over 350 elements, inorganic compounds, and organic compounds were quantified. A range of 4-9 g/kg dry fuel of particulate matter (a dilution stack sampler equipped with a 2.5-μm particle selective cyclone. Emissions were diluted 20-70 times, cooled to ambient temperature, and allowed 80 s for condensation prior to collection. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Fine particle and semivolatile organic compounds were collected on filter/PUF/XAD/PUF cartridges. Inorganic samples and mass were collected on Teflon and quartz filters. Volatile organic carbon compounds were trapped with Tenax (C8-C20), canister (C2-C12), and 2,4-dinitrophenylhydrazine impregnated cartridges (carbonyl compounds). Analysis of particle and semivolatile organic species was conducted by gas chromatography/mass spectrometry. Teflon filters were analyzed for mass by gravimetry, trace elements were analyzed by X-ray fluorescence, and ammonium was analyzed by automated colorimetry. Quartz filters were analyzed for organic and elemental carbon by thermal/optical reflectance, and ions were analyzed by ion chromatography. Select quartz filters were analyzed by accelerator mass spectrometry for carbon-12 and carbon-14 abundance. Canister and Tenax samples were analyzed by gas chromatography with a flame ionization detector, and carbonyl compounds were analyzed by high-performance liquid chromatography.
- Mcdonald, Jacob D.,Zielinska, Barbara,Fujita, Eric M.,Sagebiel, John C.,Chow, Judith C.,Watson, John G.
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p. 2080 - 2091
(2007/10/03)
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- Investigation of polycyclic aromatic hydrocarbons in fly ash from fluidized bed combustion systems
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A laboratory scale fluidized bed reactor and a bench scale 0.1 MW(th) fluidized bed combustor were used to study the effect of operating conditions on the formation of Polycyclic Aromatic Hydrocarbons (PAHs) in fly ash from fluidized bed combustion systems. A high volatile bituminous coal was chosen to investigate PAH emissions during the entire pyrolysis to oxygen-rich combustion process. During the experiments, the fluidized bed reactor was operated at temperatures between 700°C and 900°C, while the excess air ratio was varied from 0 to 1.3. An extraction and GC/MS analysis of PAHs was used in this study. Approximately 40 different PAHs were identified during the tests, of which only a few are specified by the U.S. EPA. The experimental results indicate the majority of the PAHs in the solid phase (bed and fly ash) are derived from the breakdown reactions during the processes of combustion and/or pyrolysis in a Fluidized Bed Combustion (FBC) system, although FBC systems have an efficient solid-gas mixing process and relatively long residence time. The total amount of PAHs in the fly ash was much higher than that in the raw coal and in the gas phase. Three-and four- ring aromatic compounds were the major PAHs from pyrolysis conditions, while naphthalene (two-rings) is the dominant compound in bed ash collected from oxygen-rich combustion conditions. Only naphthalene was detected in the bed ash in the FBC system. High-speed secondary air (air staging) injected into the freeboard of the FBC system is an effective method for minimizing PAH emissions, along with the other benefits including minimizing NO(x) and SO(x) emissions. A laboratory scale fluidized bed reactor and a bench scale 0.1 MWth fluidized bed combustor were used to study the effect of operating conditions on the formation of Polycyclic Aromatic Hydrocarbons (PAHs) in fly ash from fluidized bed combustion systems. A high volatile bituminous coal was chosen to investigate PAH emissions during the entire pyrolysis to oxygen-rich combustion process. During the experiments, the fluidized bed reactor was operated at temperatures between 700°C and 900°C, while the excess air ratio was varied from 0 to 1.3. An extraction and GC/MS analysis of PAHs was used in this study. Approximately 40 different PAHs were identified during the tests, of which only a few are specified by the U.S. EPA. The experimental results indicate the majority of the PAHs in the solid phase (bed and fly ash) are derived from the breakdown reactions during the processes of combustion and/or pyrolysis in a Fluidized Bed Combustion (FBC) system, although FBC systems have an efficient solid-gas mixing process and relatively long residence time. The total amount of PAHs in the fly ash was much higher than that in the raw coal and in the gas phase. Three-and four-ring aromatic compounds were the major PAHs from pyrolysis conditions, while naphthalene (two-rings) is the dominant compound in bed ash collected from oxygen-rich combustion conditions. Only naphthalene was detected in the bed ash in the FBC system. High-speed secondary air (air staging) injected into the freeboard of the FBC system is an effective method for minimizing PAH emissions, along with the other benefits including minimizing NOx and SOx emissions.
- Liu, Kunlei,Xie, Wei,Zhao, Zheng-Bao,Pan, Wei-Ping,Riley, John T.
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p. 2273 - 2279
(2007/10/03)
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- Evaluation of acute toxicity and genotoxicity of liquid products from pyrolysis of Eucalyptus grandis wood
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Slow pyrolysis of Eucalyptus grandis wood was performed in an oven laboratory, and smoke was trapped and condensed to yield liquid products. Polycyclic aromatic hydrocarbons (PAHs) and phenolic fractions were isolated from the former liquid products using adsorption column chromatography (ACC) and identified by GC/MS. Concentrations of PAH and phenolic fractions in total pyrolysis liquids were respectively 48.9 μg/g and 8.59% (w/w). Acute toxicity of total samples of pyrolysis liquids and the phenolic fraction was evaluated by means of two bioassays, namely, 24-h immobilization bioassay with Daphnia magna and Microtox(TM) bioassays, the latter employing the luminescent bacteria Photobacterium phosphoreum. Total pyrolysis liquids and the PAH fraction were evaluated for genotoxicity by the Microtox(TM) bioassay conducted using rehydrated freeze-dried dark mutant of the luminescent bacteria Vibrio fisheri strain M169. Total pyrolysis liquids and the phenolic fraction, respectively, in concentrations of 170 and 68 mg/L were able to immobilize 50% (EC50) of the D. magna population following 24-h exposure. Concentrations of 19 and 6 mg/L, respectively, for total pyrolysis liquids and phenolic fraction were the effective concentrations that resulted in a 50% (EC50) reduction in light produced by bacteria in the Microtox(TM) bioassay. Accordingly, the Microtox(TM) bioassay was more sensitive to toxic effects of both kind of samples than the D. magna bioassay, particularly for the phenolic fraction. Regarding to the genotoxicity evaluation, the results achieved by Microtox(TM) bioassay showed that total pyrolysis liquids had no genotoxic effects with and without exogenous metabolic activation using rat liver homogenate (S9). However, the PAH fraction showed toxic effects with rat liver activation and had a dose-response number (DRN) equal to 1.6, being in this way suspected genotoxic. The lowest detected concentration (LDC) of the PAH fraction able to cause genotoxic effects was 375 μg/L.
- Pimenta,Bayona,Garcia,Solanas
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p. 169 - 175
(2007/10/03)
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- The effect of oils on PAH, PCDD, PCDF, and PCB emissions from a spark engine fueled with leaded gasoline
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The effect of synthetic and mineral oils on the formation of polyaromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) in emissions from a spark ignition engine was studied on a Skoda Favorit engine fueled with leaded gasoline. The test cycle simulated urban traffic conditions on a chassis dynamometer, in accordance with the ECC 83.00 test. The data for selected PAHs as well as PCDDs, PCDFs, and PCBs congener profiles are presented. PCDD/Fs emissions for an unused oil and the oil after 10 000-km operation varied from 300 to 2000 fmol/m3, PCBs emissions from 75 to 178 pmol/m3, and PAHs emissions from 150 to 420 μg/m3. The content of PCBs in oils varied from 2 to 920 mg/kg.
- Broz, Jan,Grabic, Roman,Kilian, Juraj,Lojkasek, Milan,Marklund, Stellan,Ocelka, Tomas,Pekarek, Vladimir,Pribyl, Josef,Tydlitat, Vratislav,Vyska, Jan
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p. 1905 - 1911
(2007/10/03)
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- Influence of combustion conditions on the PCDD/F-, PCB-, PCBz- and PAH- concentrations in the post-combustion chamber of a waste incineration pilot plant
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Experiments at a pilot scale waste incinerator (0.5 MW thermal power) showed that the conditions in the postcombustion chamber (650-900°C) are strongly influencing the formation of chlorinated and non-chlorinated aromatics. Non-optimal combustion conditions resulted in increased concentrations of mono- to trichlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and polycyclic aromatic hydrocarbons (PAH), while chlorinated benzenes (PCBz), polychlorinated biphenyls (PCB) and the higher chlorinated PCDD/F are only weakly affected or even decrease. The changes in concentration of the compounds investigated over a time span of hours gave hints on 'memory effects' in this combustion zone. For mono- and dichlorinated benzenes, a high correlation (r2 = 0.80) with the international toxicity equivalent (I-TEQ) value of PCDD/F was observed. As recently has been demonstrated, this correlation can be utilized for an indirect on-line measurement of the I-TEQ by a novel laser mass spectrometric technique (REMPI-TOFMS). (C) 2000 Elsevier Science Ltd.
- Blumenstock,Zimmermann,Schramm,Kettrup
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p. 987 - 993
(2007/10/03)
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- Combustion of high calorific value waste material: Organic atmospheric pollution
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Waste tire combustion in an atmospheric fluidized-bed (AFB) reactor (7 cm i.d., 76 cm height) has been performed in a laboratory plant with the aim of studying the polycyclic aromatic hydrocarbon (PAH) emissions as a function of combustion temperature. The main aim has been to compare these organic emissions with the ones obtained when coal is burned at the same combustion conditions. PAH emissions have been analyzed in solids collected in two cyclons at the exit of the reactor and in a trap system formed by a condenser, a filter (20 μm), and an adsorbent. After PAH extraction with dimethylformamide (DMF) by sonication, fluorescence spectroscopy in the synchronous mode (FS) has been used as an analytical technique to quantify the PAHs emitted. It could be concluded that higher PAH emissions are generated when this waste material is burnt at the same conditions used for coal atmospheric fluidized-bed combustion (AFBC).
- Mastral, Ana M.,Callen, Maria S.,Murillo, Ramon,Garcia, Tomas
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p. 4155 - 4158
(2007/10/03)
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- Characterization of the combustion products of polyethylene
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Polyethylene (PE) was burned in a tube-type furnace with an air flow at a temperature of 600~900°C. Combustion products were collected with glass wool, glass fiber filter, and XAD-2 adsorbent. The analysis of the products was performed with GC-FID and GC-MSD. At low temperature, hydrocarbons were the major components, while at higher temperature the products were composed of polycyclic aromatic hydrocarbons. With the high performance of the Hewlett-Packard 6890GC-5973MSD, more compounds were identified in comparison with previous studies.
- Piao, Mingjun,Chu, Shaogang,Zheng, Minghui,Xu, Xiaobai
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p. 1497 - 1512
(2007/10/03)
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- The impact of turbulent mixing on the oxidation of a chlorinated hydrocarbon
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Combustion of chlorinated wastes can lead to the formation of hazardous byproducts. Rates of mixing of fuel and air in combustion systems can have an impact on the composition of the byproducts. Methyl chloride and methane were burned in a turbulent diffusion flame in a combustion wind tunnel with a coflow of air. Reynolds numbers were varied from 3500 to 7200. A water- cooled sampling probe was used to obtain gas samples from within the flame at a number of locations and at various Reynolds numbers. The postflame gases and particulate matter were trapped above the flames with sorbent tubes and filters. The samples were desorbed and analyzed for aromatic species and other trace products of incomplete combustion. Destruction of the methyl chloride was essentially complete for all the Reynolds numbers that were studied. Small amounts of low molecular weight chlorinated compounds were fOUnd within the flame and in the postflame gases. The major chlorinated species in the postflame gases was chloronaphthalene. Low Reynolds number flames were found to Yield larger amounts of aromatic and chlorinated aromatic species than the high Reynolds number flames. Fluoranthene was present in greater amounts on the soot particles at lower Reynolds numbers, suggesting that the rate of mixing of reactants could have an impact on the toxicity of the combustion byproducts. Combustion of chlorinated wastes can lead to the formation of hazardous byproducts. Rates of mixing of fuel and air in combustion systems can have an impact on the composition of the byproducts. Methyl chloride and methane were burned in a turbulent diffusion flame in a combustion wind tunnel with a coflow of air. Reynolds numbers were varied from 3500 to 7200. A water-cooled sampling probe was used to obtain gas samples from within the flame at a number of locations and at various Reynolds numbers. The postflame gases and particulate matter were trapped above the flames with sorbent tubes and filters. The samples were desorbed and analyzed for aromatic species and other trace products of incomplete combustion. Destruction of the methyl chloride was essentially complete for all the Reynolds numbers that were studied. Small amounts of low molecular weight chlorinated compounds were found within the flame and in the postflame gases. The major chlorinated species in the postflame gases was chloronaphthalene. Low Reynolds number flames were found to yield larger amounts of aromatic and chlorinated aromatic species than the high Reynolds number flames. Fluoranthene was present in greater amounts on the soot particles at lower Reynolds numbers, suggesting that the rate of mixing of reactants could have an impact on the toxicity of the combustion byproducts.
- Yang, Gosu,Jones, A. Daniel,Kennedy, Ian M.
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p. 1265 - 1268
(2007/10/03)
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- Effects of an oxidation catalytic converter and a biodiesel fuel on the chemical, mutagenic, and particle size characteristics of emissions from a diesel engine
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This study was conducted to obtain additional information on exhaust emissions with potential health importance from an indirect injection diesel engine, typical of those in use in underground mines, when operated using a soy-derived, fatty-acid mono-ester (or biodiesel) fuel and an oxidation catalytic converter (OCC). Compared to emissions with the diesel fuel without the OCC, use of the diesel (D2) and biodiesel fuel with the OCC had similar reductions (50-80%) in total particulate matter (TPM). The solid portion of the TPM was lowered with the biodiesel fuel. Particle-associated polynuclear aromatic hydrocarbon and 1-nitropyrene emissions were lower with use of the biodiesel fuel as compared to the D2 fuel, with or without the OCC. Vapor- phase PAH emissions were reduced (up to 90%) when the OCC was used with either fuel. Use of the OCC resulted in over 50% reductions in both particle and vapor-phase-associated mutagenic activity with both fuels. No vapor- phase-associated mutagenic activity was detected with the biodiesel fuel; only very low levels were detected with the D2 fuel and the OCC. Use of the OCC caused a moderate shift in the particle size/volume distribution of the accumulation mode particles to smaller particles for the diesel fuel and a reduction of particle volume concentrations at some of the tested conditions for both fuels. The nuclei mode did not contribute significantly to total particle volume concentrations within the measured particle size range (~0.01-1.0 μm). The biodiesel fuel reduced total particle volume concentrations. Overall, use of this OCC for the engine conditions tested with the biodiesel fuel, in particular, resulted in generally similar or greater reductions in emissions than for use of the D2 fuel. Use of the biodiesel fuel should not increase any of the potentially toxic, health- related emissions that were monitored as part of this study. Detailed information necessary to evaluate impact of using a biodiesel fuel on potentially health-related emissions from a diesel engine typical of those used in many underground mining operations are provided. Compared to emissions with the diesel fuel without the oxidation catalytic converter (OCC), use of the diesel (D2) and biodiesel fuel with the OCC had a similar reductions in total particulate matter (TPM). The solid portion of the TPM was lowered with the biodiesel fuel. Particle-associated polynuclear aromatic hydrocarbon and 1-nitropyrene emissions were lower with use of the biodiesel fuel as compared to the D2 fuel, with or without the OCC.
- Bagley, Susan T.,Gratz, Linda D.,Johnson, John H.,McDonald, Joseph F.
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p. 1183 - 1191
(2007/10/03)
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- Alkali Metal Mediated Conversion of Arene Oxides and Arene Imines into Aromatic Hydrocarbons
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K-Region oxides and imines of phenanthrene, chrysene, benzanthracene, and dibenzanthracene react in tetrahydrofuran with lithium and sodium to give the parent hydrocarbons. In the presence of excessive metal, the latter are converted into dianions from which the parent compounds can be regenerated upon quenching with oxygen. Metalate derivatives of the oxides and imines are proposed to be the corresponding reaction intermediates in the deoxygenation and deamination processes.
- Elmalak, Omar,Rabinovitz, Mordecai,Blum, Jochanan
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p. 291 - 292
(2007/10/02)
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- A Rapid, Convergent, and Regioselective Synthesis of Anthracenes
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Anthracenes are obtained in moderate to good yield by the simultaneous treatment of benzocyclobutenols and halobenzenes with LTMP in tetrahydropyran.In the key step of this one-pot process, o-toluoyl anion intermediates from the known ring-opening of benzocyclobutenoxides add to halobenzene derived arynes.Methoxy-substituted benzocyclobutenols which are readily made regiospecifically by known methods also react regiospecifically with the single benzyne generated from either a 2- or 3-haloanisole.For example, the only trimethoxyanthracene isolated (48percent yield) from the reaction of 6-methoxybenzocyclobutenol (8) with 5-chloro-1,3-dimethoxybenzene is the 1,3,8-isomer 20.When 1,2-dihydrocyclobutaphenanthren-1-ol (14) and/or halonaphthalenes are the reactants, benzannulated anthracenes are formed; e.g., tribenzanthracene in 68percent yield from 14 and bromonaphthalene.In another extension, pentaphene (31) was made in one pot from o-dichlorobenzene.
- Fitzgerald, John J.,Drysdale, Neville E.,Olofson, R. A.
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p. 7122 - 7126
(2007/10/02)
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- Cycloaromatization of α-oxoketene dithioacetals and β-oxodithioacetals with benzyl-,1-(naphthylmethyl) and 2-(naphthylmethyl)magnesium halides: Synthesis of condensed polynuclear aromatic hydrocarbons
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An efficient route for the synthesis of substituted naphthalenes, phenanthrenes and other polynuclear aromatic hydrocarbons has been developed. The methodology involves 1,2- (or sequential 1,4- and 1,2-) addition of either benzyl, 1-(naphthylmethyl) or 2-(naphthylmethyl) magnesium halides to α-oxoketene dithioacetals or β-oxodithioacetals followed by borontrifluoride etherate catalyzed cycloaromatization of the resulting carbinols.
- Srinivasa Rao,Balu, Maliakel P.,Ila, Hiriyakkanavar,Junjappa, Hiriyakkanavar
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p. 3499 - 3510
(2007/10/02)
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- FLOW-VACUUM PYROLYSIS OF DIBENZOTRICYCLO2,5>-DECA-3,7,9-TRIENE (syn-DIBENZONENITZESCU'S HYDROCARBON) AND OF TRIBENZOTRICYCLO2,5>DECA-3,7,9-TRIENE (TRIBENZO-NENITZESCU'S HYDROCARBON)
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Retro-diene reactions are the favoured pathways in the flow-vacuum pyrolysis of both title hydrocarbons 6 and 7. The main reactions products in the pyrolysis of 6 are: the angular dimer 17 of benzocyclobutene (Cava's dimer), naphthalene, dibenzocyclooctene and benzobiphenylene. From the pyrolysis products of 7, anthracene, Cava's dimer 17 and dibenzocyclooctene were identified. The reaction mechanisms are discussed and a comparison with pyrolyses of related Nenitzescu's hydrocarbons is presented.
- Banciu, Mircea D.,Pop, Mircea,Petride, Aurica,Stanescu, Michaela Dina
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p. 907 - 916
(2007/10/03)
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- Photochemistry of Stilbenes. 8. Eliminative Photocyclization of o-Methoxystilbenes
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The synthetic value of the eliminative photocyclization of o-methoxystilbenes to give phenanthrenes with loss of the element of methanol has been enhanced by the use of tert-butyl alcohol as the solvent and sulfuric acid as a catalyst. 2-Methoxy-5-X-stilbenes and 2-methoxy-3-X-stilbenes undergo this photoreaction to produce the corresponding 2-X-phenanthrenes and 4-X-phenanthrenes, respectively.This regioselective photochemical route to these particular types of substituted phenanthrenes represents an improvement synthetically over the well-known oxidative photocyclization method with meta-substituted stilbenes, from which approximately 1:1 mixtures of 2-substituted and 4-substituted phenanthrenes usually are obtained.An attempt to extend the scope of this eliminative photocyclization method to the synthesis of benzanthracene by the ultraviolet irradiation of 3-methoxy-2-styrylnaphthalene was not successful, but this synthetic objective was achieved in an alternative way by the eliminative photocyclization of 5,6,7,8-tetrahydro-3-methoxy-2-styrylnaphthalene followed by oxidation of the resulting 8,9,10,11-tetrahydrobenzanthracene with DDQ.
- Mallory, Frank B.,Rudolph, M. Jonathan,Oh, Soon M.
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p. 4619 - 4626
(2007/10/02)
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- Studies in the Rearrangement of Spiranes: Synthesis of 1',2',3',4'-Tetrahydrospiro and Its Derivatives and Their Rearrangement on Catalytic Dehydrogenation
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1',2',3',4'-Tetrahydrospiro (2a) and its 7'-methyl (2b), 5',8'-dimethyl (2c) and 6',7'-cyclohexeno (2d) derivatives have been synthesized starting from the anhydride of indane-2-carboxy-2-acetic acid and appropriate aromatic hydrocarbons.These spiranes when dehydrogenated using 10percent Pd-C as catalyst, underwent smooth rearrangement giving benzanthracene (7a), 2-methylbenzanthracene (7b), 1,4-dimethylbenzanthracene (7c) and pentaphene (7d) respectively.
- Chatterjee, D. N.,Guha, Jayasree
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p. 402 - 406
(2007/10/02)
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- Synthesis and Deamination of 7,12-Dihydrobenzanthracen-7,12-imines. A New Benzanthracene Synthesis
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The Diels-Alder reaction between isoindoles (7) and 1-naphthalyne, as generated from 1-bromo-2-fluoronaphthalene (11a), 1-bromo-2-iodonaphthalene (11b), or 1-bromo-2-naphthyl p-toluenesulfonate (11c), affords the corresponding 7,12-dihydrobenzanthracen-7,12-imine (17).Oxidative deamination of 17 with m-chloroperbenzoic acid gives the polyhalogenated benzanthracenes(3, 19a-d) in fair to good overall yields.A similar sequence with 7 and 5,6,7,8-tetrafluoro-1-naphthalyne, as generated from 1,2,3,4-tetrafluoro-5-chloronaphthalene (14a), 1,2,3,4-tetrafluoro-5-bromonaphthalene (14b), or 6-bromo-1,2,3,4-tetrafluoro- 5-naphthyl p-toluenesulfonate (16), gives, after deamination of the intermediate benzanthracenimine 18, benzanthracenes 5 and 19e in low overall yield.
- Gribble, Gordon W.,LeHoullier, Craig S.,Sibi, Mukund P.,Allen, Robert W.
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p. 1611 - 1616
(2007/10/02)
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- Twin Benzoannulation of Naphthalene via 1,3-, 1,6-, and 2,6-Naphthodiyne Synthetic Equivalents. New Syntheses of Triphenylene, Benzanthracene, and Naphthacene
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New syntheses of triphenylene (4), benzanthracene (5), naphthacene (6), and the tetramethylated derivatives 17 and 25 are described that feature, as the key step, the formal Diels-Alder cycloaddition between a naphthodiyne synthon (1, 2, or 3) and a furan (10 or 14).Subsequent deoxygenation affords the arene in 16-28percent overall yield from dibromo ditosylate 7, 8, or 9.The latter are prepared in two steps from commercially available 2,3- or 2,7-dihydroxynaphthalene, and, with phenyllithium, serve as synthetic equivalents of 1, 2, and 3.The X-ray structure of the anti isomer of 23 is discussed in some detail.
- Gribble, Gordon W.,Perni, Robert B.,Onan, Kay D.
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p. 2934 - 2939
(2007/10/02)
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- Preparation of Isobenzofuran-Aryne Cycloadducts
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A one-pot procedure is described for carrying out the sequence 1,4-elimination of acetal 1 to form isobenzofuran; the formation of 1,3-dilithioisobenzofuran; the conversion to 1,3-bis(trimethylsilyl)isobenzofuran (5); the generation of arynes and cycloaddition to 5.This method allows the use of lithium tetramethylpiperidide induced dehydrohalogenation of haloaromatics to generate the arynes, a procedure which fails with unsilylated isobenzofuran due to the acidity of the 1,3-protons.The protiodesilylation of the cycloadducts occurs with surprising ease, upon treatmentwith either tetraalkylammonium fluoride/THF or base (potassium tert-butoxide or KOH) in Me2SO, to furnish the novel unsubstituted isobenzofuran-aryne adducts.Three examples are given, utilizing benzyne, 1-naphthalyne, and 3-pyridine.Procedures for subsequent deoxygenation of the cycloadducts to anthracene, benzanthracene, and benzisoquinoline, respectively, are described.The cycloadduct precursor of benzanthracene is shown to undergo highly regioselective reduction on treatment with lithium tri-tert-butoxyaluminohydride/triethylborane, with preferential attack occurring at the more accessible 7-position.
- Crump, Stephen L.,Netka, Jill,Rickborn, Bruce
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p. 2746 - 2750
(2007/10/02)
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- DEOXYGENATION OF TERTIARY AMINE N-OXIDES AND ARENE OXIDES BY IRON (II) PORPHYRIN AS A MODEL OF CYTOCHROME P-450 DEPENDENT REDUCTION
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Tetraphenylporphiratoiron (II), a model complex of reduced cytochrome P-450, reduces several substrates such as tertiary amine N-oxides and arene oxides at room temperature in anaerobic conditions.A process for the direct oxene transfer from oxide to reduced iron porphyrin is suggested.KEYWORDS - cytochrome P-450; reduction; deoxygenation; tertiary amine N-oxide; tetraphenylporphinatoiron (II); oxene transfer; arene oxide; ferryl oxide
- Miyata, Naoki,Santa, Tomofumi,Hirobe, Masaaki
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p. 377 - 380
(2007/10/02)
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- Reductive Cyclization of Keto Acids to Polycyclic Aromatic Hydrocarbons by Hydroiodic Acid-Red Phosphorus
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Hydroiodic acid-red phosphorus in acetic acid causes ring closure of o-naphthoylbenzoic acids and of o-naphthoylnaphthoic acids to yield benzanthracene and dibenzanthracenes
- Platt, Karl L.,Oesch, Franz
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p. 2601 - 2603
(2007/10/02)
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- SYNTHESIS OF 3-METHYLCHOLANTHRENE
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A novel synthesis of 3-methylcholanthrene is described which is operationally simpler than the method in current use and is potentially applicable to the synthesis of a wide range of other polycyclic hydrocarbons and their oxidized carcinogenic metabolites.
- Jacobs, Stephen A.,Harvey, Ronald G.
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p. 1093 - 1096
(2007/10/02)
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- An Expeditious Synthesis of Benzanthracene and some of Its Oxygenated Derivatives
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Benzanthracenes were synthesized by reaction of ortho-quinodimethane and 1,2-dihydronaphthalenes.
- Levy, Louis A.,Pruitt, Lynn
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p. 227 - 228
(2007/10/02)
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