- Regiospecifically Fluorinated Polycyclic Aromatic Hydrocarbons via Julia-Kocienski Olefination and Oxidative Photocyclization. Effect of Fluorine Atom Substitution on Molecular Shape
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A modular synthesis of regiospecifically fluorinated polycyclic aromatic hydrocarbons (PAHs) is described. 1,2-Diarylfluoroalkenes, synthesized via Julia-Kocienski olefination (70-99% yields), were converted to isomeric 5- and 6-fluorobenzo[c]phenanthrene, 5-and 6-fluorochrysene, and 9- and 10-benzo[g]chrysene (66-83% yields) by oxidative photocyclization. Photocyclization to 6-fluorochrysene proceeded more slowly than conversion of 1-styrylnaphthalene to chrysene. Higher fluoroalkene dilution led to a more rapid cyclization. Therefore, photocyclizations were performed at higher dilutions. To evaluate the effect of fluorine atom on molecular shapes, X-ray data for 5- and 6-fluorobenzo[c]phenanthrene, 6-fluorochrysene, 9- and 10-fluorobenzo[g]chrysene, and unfluorinated chrysene as well as benzo[g]chrysene were obtained and compared. The fluorine atom caused a small deviation from planarity in the chrysene series and decreased nonplanarity in the benzo[c]phenanthrene derivatives, but its influence was most pronounced in the benzo[g]chrysene series. A remarkable flattening of the molecule was observed in 9-fluorobenzo[g]chrysene, where the short 2.055 ? interatomic distance between bay-region F-9 and H-8, downfield shift of H-8, and a 26.1 Hz coupling between F-9 and C-8 indicate a possible F-9···H-8 hydrogen bond. In addition, in 9-fluorobenzo[g]chrysene, the stacking distance is short at 3.365 ? and there is an additional interaction between the C-11-H and C-10a of a nearby molecule that is almost perpendicular.
- Banerjee, Shaibal,Sinha, Saikat,Pradhan, Padmanava,Caruso, Alessio,Liebowitz, Daniel,Parrish, Damon,Rossi, Miriam,Zajc, Barbara
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Read Online
- Alumina-Mediated π-Activation of Alkynes
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The ability to induce powerful atom-economic transformation of alkynes is the key feature of carbophilic π-Lewis acids such as gold- and platinum-based catalysts. The unique catalytic activity of these compounds in electrophilic activations of alkynes is explained through relativistic effects, enabling efficient orbital overlapping with π-systems. For this reason, it is believed that noble metals are indispensable components in the catalysis of such reactions. In this study, we report that thermally activated γ-Al2O3activates enynes, diynes, and arene-ynes in a manner enabling reactions that were typically assigned to the softest π-Lewis acids, while some were known to be triggered exclusively by gold catalysts. We demonstrate the scope of these transformations and suggest a qualitative explanation of this phenomenon based on the Dewar-Chatt-Duncanson model confirmed by density functional theory calculations.
- Akhmetov, Vladimir,Amsharov, Konstantin,Feofanov, Mikhail,Sharapa, Dmitry I.
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supporting information
p. 15420 - 15426
(2021/09/30)
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- Chrysene-Based Blue Emitters
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Chrysene and its bisbenzannulated homologue, naphtho[2,3-c]tetraphene, were synthesized through a PtCl2-catalyzed cyclization of alkynes, which also furnished corresponding biaryls subsequent to a Glaser coupling reaction of the starting alkynes. The optoelectronic properties of 5,5′-bichrysenyl and 6,6′-binaphtho[2,3-c]tetraphene were compared to their chrysene-based “monomers”. Oxidative cyclodehydrogenations of bichrysenyl and its higher homologue towards large nanographenes were also investigated.
- Nathusius, Marvin,Ejlli, Barbara,Rominger, Frank,Freudenberg, Jan,Bunz, Uwe H. F.,Müllen, Klaus
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p. 15089 - 15093
(2020/10/21)
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- Construction of Phenanthrenes and Chrysenes from β-Bromovinylarenes via Aryne Diels-Alder Reaction/Aromatization
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A highly efficient transition-metal-free general method for the synthesis of polycyclic aromatic hydrocarbons like phenanthrenes and chrysenes (and tetraphene) from β-bromovinylarenes and arynes has been developed. The reactions proceed via an aryne Diels-Alder (ADA) reaction, followed by a facile aromatization. This is the first report on direct construction of chrysenes (and tetraphene) using the ADA approach. Unlike the literature method which is limited to only 9/10-substituted derivatives, this method gives access to a wide variety of functionalized phenanthrenes.
- Singh, Vikram,Verma, Ram Subhawan,Khatana, Anil K.,Tiwari, Bhoopendra
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p. 14161 - 14167
(2019/10/28)
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- A novel and efficient synthesis of phenanthrene derivatives via palladium/norbornadiene-catalyzed domino one-pot reaction
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Herein we report a novel palladium-catalyzed reaction that results in phenanthrene derivatives using aryl iodides, ortho-bromoben-zoyl chlorides and norbornadiene in one pot. This dramatic transformation undergoes ortho-C–H activation, decarbonylation and subsequent a retro-Diels–Alder process. Pleasantly, this protocol has a wider substrate range, shorter reaction times and higher yields of products than previously reported methods.
- Zhong, Yue,Wu, Wen-Yu,Yu, Shao-Peng,Fan, Tian-Yuan,Yu, Hai-Tao,Li, Nian-Guang,Shi, Zhi-Hao,Tang, Yu-Ping,Duan, Jin-Ao
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supporting information
p. 291 - 298
(2019/02/20)
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- Oxidative, Iodoarene-Catalyzed Intramolecular Alkene Arylation for the Synthesis of Polycyclic Aromatic Hydrocarbons
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A catalytic, metal-free and chemoselective oxidative intramolecular coupling of arene and alkene C?H bonds is reported. The active hypervalent iodine (HVI) reagent, generated catalytically in situ from iodotoluene and meta-chloroperoxybenzoic acid (m-CPBA), reacts with o-vinylbiphenyls to generate polyaromatic hydrocarbons in up to 95 % yield. Experimental evidence suggests the reactions proceed though vinyliodonium and, possibly, vinylenephenonium intermediates.
- Zhao, Zhensheng,Britt, Liam H.,Murphy, Graham K.
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p. 17002 - 17005
(2018/11/01)
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- Further insight into the photochemical behavior of 3-aryl-N-(arylsulfonyl)propiolamides: tunable synthetic route to phenanthrenes
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Reported herein is further insight into the photochemical behaviour of 3-aryl-N-(arylsulfonyl)-propiolamides, which provides a straightforward way to access meaningful phenanthrenes. Mechanistic investigation indicated that aryl migration, C-C coupling, 1,3-hydrogen shift, desulfonylation and elimination were involved in the process. Moreover, this protocol allowed for scale-up using a flow reactor.
- Chen, Ming,Zhao, Xinxin,Yang, Chao,Wang, Yanpei,Xia, Wujiong
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p. 12022 - 12026
(2017/03/01)
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- Convenient Phenacene Synthesis by Sequentially Performed Wittig Reaction and Mallory Photocyclization Using Continuous-Flow Techniques
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Various phenacenes possessing chrysene, picene, and fulminene frameworks were prepared by using a continuous-flow synthetic protocol in which Wittig reaction affording diarylethenes and their Mallory photocyclization producing phenacene skeletons were sequentially performed. The Wittig reaction solution, containing the diaryl ethene obtained from an arylaldehyde and an arylmethyltriphenylphosphonium salt, was mixed with an iodine solution in the flow system and, subsequently, the solution was subjected to the photoreaction. Desired phenacenes were obtained with high to moderate chemical yield. For the present protocol, isolation of the intermediary diarylethene, which is the key precursor of the phenacene, is unnecessary. The approach provides a convenient method to supply a variety of phenacene samples, which are needed for initial systematic surveys in material science.
- Okamoto, Hideki,Takahashi, Haruhiko,Takane, Takamitsu,Nishiyama, Yasuhiro,Kakiuchi, Kiyomi,Gohda, Shin,Yamaji, Minoru
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p. 2949 - 2957
(2017/06/27)
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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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p. 262 - 265
(2017/01/24)
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- A method of chemical synthesis * ring
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The invention discloses a method for chemically compounding (img file='DDA0000712956880000012. TIF' wi='52' he='60'/) rings. The method for preparing the formula I (img file='DDA0000712956880000012. TIF' wi='52' he='60'/) rings (which also is a (img file='DDA0000712956880000013. TIF' wi='55' he='57'/) ring) comprises the steps that 2 - (4 - alkoxy phenyl) ethinyl acetophenone in the formula II and 2-alkynylbenzaldehydes in a formula III are dissolved in organic solvent, then generate a cyclization reaction after adding an accelerant in a system to stir, and a compound showed in the formula I is obtained after reacting. The method for chemically compounding the (img file='DDA0000712956880000012. TIF' wi='52' he='60'/) rings is a one-pot synthesis method, compounds the compound in a manual way for the first time, and raw materials in the method are low in cost and are easy to obtain, are simple in reaction operation, mild in conditions and suitable for large-scale preparation, and have important application value. (img file='DDA0000712956880000011. TIF' wi='1430' he='485'/).
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Paragraph 0024; 0025
(2018/02/04)
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- Br?nsted Acid-Promoted One-Pot Synthesis of Chrysene Derivatives via Isochromenylium Intermediate Formed in Situ
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Trifluoromethanesulfonic acid (HOTf) promoted cross-coupling of ortho-[2-(4-methoxylphenyl)-alkynyl]acetophenones with ortho-alkynylbenzaldehydes affording chrysene derivatives has been developed. The present cascade reaction provides a facile one-pot synthesis of multisubstituted chrysenes as well as naked chrysene under mild conditions. The mechanism experimental results demonstrate isochromenylium is a key intermediate for this transformation.
- Guo, Biao,Zhou, Yiming,Zhang, Lei,Hua, Ruimao
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p. 7635 - 7641
(2015/08/18)
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- Base-Promoted/Gold-Catalyzed Intramolecular Highly Selective and Controllable Detosylative Cyclization
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A highly selective, controllable and synthetically useful base-promoted intramolecular detosylative cyclization of bis-N-tosylhydrazones has been achieved, affording N-containing heterocycles and cyclic olefins under transition-metal-free or gold-catalyzed procedures, respectively. Moreover, an effective and practical metal-free or gold-catalyzed approach to synthesize polycyclic aromatic compounds is also reported. Basic cyclizations: A highly selective, controllable, and synthetically useful base-promoted intramolecular detosylative cyclization of bis-N-tosylhydrazones affords N-containing heterocycles and cyclic olefins under transition-metal-free or gold-catalyzed procedures, respectively. Moreover, an effective and practical metal-free or gold-catalyzed approach to synthesize polycyclic aromatic compounds is also reported.
- Zhu, Chenghao,Qiu, Lin,Xu, Guangyang,Li, Jian,Sun, Jiangtao
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supporting information
p. 12871 - 12875
(2015/09/07)
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- Use of external radical sources in flash vacuum pyrolysis to facilitate cyclodehydrogenation reactions in polycyclic aromatic hydrocarbons
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A new process to facilitate the cyclodehydrogenation of polycyclic aromatic hydrocarbons (PAHs) in flash vacuum pyrolysis (FVP) using an external radical source is described. Using hexanes as an external radical source the conversion of various PAHs to their cyclodehydrogenated products is vastly increased. Various other volatile organic compounds were also examined to determine their ability to act as external radical sources in FVP.
- Amick, Aaron W.,Martin, Sara E.
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p. 1338 - 1343
(2014/11/08)
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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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- Efficient synthetic photocyclization for phenacenes using a continuous flow reactor
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The continuous flow reaction technique has been applied to the photocyclization of 1,2-diarylethenes, the so-called Mallory reaction, to afford phenacenes in high chemical yields and efficiencies (114-288mg h-1). The present technique will allow us to produce several grams of phenacenes at a time.
- Okamoto, Hideki,Takane, Takamitsu,Gohda, Shin,Kubozono, Yoshihiro,Sato, Kaori,Yamaji, Minoru,Satake, Kyosuke
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p. 994 - 996
(2014/07/22)
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- Bismuth-catalyzed synthesis of polycyclic aromatic hydrocarbons (PAHs) with a phenanthrene backbone via cyclization and aromatization of 2-(2-arylphenyl)vinyl ethers
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The reaction of 2-(2-arylphenyl)vinyl ethers in the presence of a catalytic amount of bismuth(III) triflate gave substituted phenanthrenes in excellent yields under mild reaction conditions. The reaction was also applied to the construction of other polycyclic aromatic hydrocarbons (PAHs), such as chrysene, helicene, and pyrene having a phenanthrene backbone, via regioselective cyclization. This method has the advantages of easy availability of the cyclization precursors, operational simplicity, and high reaction efficiency.
- Murai, Masahito,Hosokawa, Naoki,Roy, David,Takai, Kazuhiko
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supporting information
p. 4134 - 4137
(2014/09/30)
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- 3,6,9,12-tetrasubstituted chrysenes: Synthesis, photophysical properties, and application as blue fluorescent OLED
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A short synthesis of unsubstituted chrysene is described to provide a cheap source of this compound. This chrysene was used to prepare 3,6,9,12- tetrabromochrysene, which was subsequently transformed into various 3,6,9,12-tetrasubstituted chrysenes bearing four aryl, alkynyl, or amino groups by means of the Suzuki, Sonogashira, or Buchwald-Hartwig coupling reaction, respectively. These substituents result in large bathochromic shifts in the chrysene absorption and emission spectra. These new chrysene derivatives show blue fluorescent emission (401-471 nm) with high quantum yields (0.44-0.87). DFT calculations on these chrysenes rationalize well the substituent effects on their HOMO and LUMO energy levels. One representative chrysene (6g) was used as a blue fluorescent emitter in an OLED device that showed an outstanding external quantum efficiency (η = 6.31%) with blue emission [CIE (x, y) = (0.13, 0.20)] and a low turn-on voltage (3.0 V).
- Wu, Tien-Lin,Chou, Ho-Hsiu,Huang, Pei-Yun,Cheng, Chien-Hong,Liu, Rai-Shung
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p. 267 - 274
(2014/01/17)
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- Light-induced carbocyclization of iodoalkenes
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The direct irradiation of iodoalkenes leads to the formation of carbon-centered radical by homolysis of the C-I bond. The photoreaction is used in cyclizations with formation of six membered rings.
- Campos-Gómez, Esther,Campos, Pedro J.,González, Héctor F.,Rodríguez, Miguel A.
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p. 4292 - 4295
(2012/07/16)
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- Straightforward synthesis of phenanthrenes from styrenes and arenes
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Semi-one-pot synthesis of phenanthrenes from styrenes and arenes was developed through cross-dehydrogenative coupling. A sequence of Heck-type coupling and photo-cyclization were involved and a variety of functionalities were tolerated. This method provides an effective and practical protocol towards the synthesis of substituted phenanthrenes. The Royal Society of Chemistry 2012.
- Li, Hu,He, Ke-Han,Liu, Jia,Wang, Bi-Qin,Zhao, Ke-Qing,Hu, Ping,Shi, Zhang-Jie
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supporting information; experimental part
p. 7028 - 7030
(2012/08/07)
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- Rhodium(II)-catalyzed cyclization of bis(N-tosylhydrazone)s: An efficient approach towards polycyclic aromatic compounds
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Ahead of the PAC: Polycyclic aromatic compounds (PACs) can be easily accessed by the combination of Suzuki-Miyaura cross-coupling and a [Rh 2(OAc)4]-catalyzed carbene reaction using easily available bis(N-tosylhydrazone)s as intermediates (see scheme; Ts=4-toluenesulfonyl). Copyright
- Xia, Ying,Liu, Zhenxing,Xiao, Qing,Qu, Peiyuan,Ge, Rui,Zhang, Yan,Wang, Jianbo
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p. 5714 - 5717
(2012/07/28)
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- Facile synthesis of picene from 1,2-Di(1-naphthyl)ethane by 9-fluorenone-sensitized photolysis
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A facile formation of picene was achieved by photosensitization of 1,2-di(1-naphthyl)ethane using 9-fluorenone as a sensitizer. This sensitized photoreaction is the first photochemical cyclization of ethylene-bridged naphthalene moieties to afford the picene skeleton. 5,8-Dibromopicene, prepared by this procedure using 1,2-di[1-(4-bromonaphthyl)]ethane as the substrate, was readily converted to novel functionalized picenes by conventional substitution and cross-coupling reactions.
- Okamoto, Hideki,Yamaji, Minoru,Gohda, Shin,Kubozono, Yoshihiro,Komura, Noriko,Sato, Kaori,Sugino, Hisako,Satake, Kyosuke
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scheme or table
p. 2758 - 2761
(2011/06/26)
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- Palladium-catalyzed intramolecular C-H activation: A synthetic approach towards polycyclic aromatic hydrocarbons
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A simple and convenient synthetic protocol for the construction of polycyclic aromatic hydrocarbons has been developed. A variety of phenanthrene, benzo[c]phenanthrene and chrysene derivatives was synthesized via Pd-catalyzed intramolecular C-H activation followed by acid-catalyzed water elimination.
- Paul, Sunanda,Jana, Rathin,Ray, Jayanta K.
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experimental part
p. 1463 - 1468
(2010/08/20)
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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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- Synthesis of substituted benzene derivatives by homo- and hetero-coupling of 2-bromobenzaldehyde and bromovinylaldehydes followed by McMurry coupling
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A convenient synthetic approach to substituted benzene derivatives by modified Ullmann cross-coupling of 2-bromobenzaldehyde and bromovinylaldehydes followed by intramolecular McMurry coupling has been developed.
- Some, Surajit,Dutta, Bishnupada,Ray, Jayanta K.
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p. 1221 - 1224
(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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- Short and efficient synthesis of coronene derivatives via ruthenium-catalyzed benzannulation protocol
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TpRuPPh3(CH3CN)2PF6 (3 mol %) was very active in catalytic benzannulation of 1-phenyl-2-ethynylbenzenes in dichloroethane (60 °C, 36 h) to afford phenanthrene in 95% yield. This method is applicable to the synthesis of various polycyclic aromatic hydrocarbons via two- and four-fold benzannulations, including various substituted coronene derivatives (53-86% yields) using this catalyst at a moderate loading (10 mol %).
- Shen, Hung-Chin,Tang, Jhih-Meng,Chang, Hsu-Kai,Yang, Chia-Wei,Liu, Rai-Shung
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p. 10113 - 10116
(2007/10/03)
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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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- 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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- Heck vinylation of aryl iodides by a silica sol-gel entrapped Pd(II) catalyst and its combination with a photocyclization process
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(Equation presented) Silica sol-gel encaged PdCl2(PPh 3)2 is a recyclable catalyst for the Heck vinylation of aryl iodides. It is possible to couple the Heck reaction with photocyclization in a one-pot process.
- Hamza, Khalil,Abu-Reziq, Raed,Avnir, David,Blum, Jochanan
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p. 925 - 927
(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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- 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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- Transient puffs of trace organic emissions from a batch-fed waste propellant incinerator
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Emissions data have been obtained from a waste propellant incinerator. The incinerator is a dual fixed hearth, controlled air incinerator equipped with acid gas and particulate scrubbing. Puffing has been evident in this waste propellant incinerator by spikes in the CO concentration. Transient puffs of organics may travel down the combustion chambers and lead to stack emissions. The major conclusions from this study are that (1) transient puffs are formed due to the semi-batch feed nature of the combustion process (causing a local oxygen deficiency) and high water content of the desensitized propellant; (2) in batch-fed combustors, puffs can contribute to most of the organic emissions (which are relatively low) measured with US EPA sampling and analytical methods; (3) it is estimated that batch-fed combustion contributes up to 7-18 times more emissions than steady-state combustion will generate; (4) by applying dispersion analyses to determine the amount of oxygen deficiency in the flame zone, the combustion zone concentration of CO during batch-fed operation could be as high as 160,000 ppm, compared to a measured peak stack concentration of 1200 ppm CO; and (5) an organic sample is collected and averaged over at least a 2-h period that smooths out the transient peaks of organics emissions during batch-fed operation. For emissions that are associated with long-term potential health impacts, this is an appropriate sampling method. However, if a compound has a short-term potential health impact, it may be important to measure the time-resolved emissions of the compound.
- Hart, John R.
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p. 559 - 569
(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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- 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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- Evolution of products in the combustion of scrap tires in a horizontal, laboratory scale reactor
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A horizontal laboratory reactor was used to study the evolution of byproducts from the combustion of scrap tires at five nominal temperatures (ranging from 650 to 1050 °C) and different oxygen:sample ratios A model was used to calculate the bulk air ratio (λ), and the oxygen consumption was discussed considering this ratio λ. More than 100 volatile and semivolatile compounds were identified and quantified by gas chromatography mass spectrometry, plotting their yields vs the bulk air ratio and temperature. Five different behaviors considering the bulk air ratio and the temperature were identified.
- Fullana,Font,Conesa,Blasco
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p. 2092 - 2099
(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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- Ground state EDA complex formation between [60]fullerene and a series of polynuclear aromatic hydrocarbons
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Formation constants of 1:1 adducts of [60]fullerene with naphthalene, phenanthrene, anthracene, pyrene and chrysene have been determined in CCl4 medium. Ionisation potentials of donor molecules and charge transfer (CT) transition energies of the [60]fullerene adducts have been found to correlate in accordance with the Mulliken equation. From such correlation the electron affinity of [60]fullerene has been calculated to be 2.32 eV in solution. A good estimate for the sp2C-sp2C resonance integral β in benzenoid hydrocarbons has also been obtained from the observed CT transition energies.
- Datta, Kakali,Banerjee, Manas,Seal, Bejoy K.,Mukherjee, Asok K.
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p. 531 - 534
(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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- 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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- 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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- Kinetics of the reduction of dialkyl peroxides. New insights into the dynamics of dissociative electron transfer
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The concerted dissociative reduction of di-tert-butyl peroxide (DTBP), dicumyl peroxide (DCP), and di-n-butyl peroxide (DNBP) is evaluated by both heterogeneous and homogeneous electron transfer using electrochemical methods. Electrochemical and thermochemical determination of the O-O bond energies and the standard potentials of the alkoxyl radicals allow the standard potentials for dissociative reduction of the three peroxides in N,N-dimethylformamide and acetonitrile to be evaluated. These values allowed the kinetics of homogeneous ET reduction of DTBP and DCP by a variety of radical anion donors to be evaluated as a function of overall driving force. Comparison of the heterogeneous ET kinetics of DTBP and DNBP as a function of driving force for ET allowed the distance dependence on the reduction kinetics of the former to be estimated. Results indicate that the kinetics of ET to DTBP is some 0.8 order of magnitude slower in reactivity than DNBP because of a steric effect imposed by the bulky tert-butyl groups. Experimental activation parameters were measured for the homogeneous reduction of DTBP with five mediators, covering a range of 0.4 eV in driving force over the temperature range -30 to 50°C in DMF. The temperature dependence of the kinetics leads to unusually low preexponential factors for this series. The low preexponential factor is interpreted in terms of a nonadiabatic effect resulting from weak electronic coupling between the reactant and product surfaces. Finally, the data are discussed in the context of recent advances of dissociative electron transfer reported by Saveant and by German and Kuznestov. In total the results suggest that these peroxides undergo a nonadiabatic dissociative electron transfer and represent the first reported class of compounds where this effect is reported.
- Donkers, Robert L.,Maran, Flavio,Wayner, Danial D. M.,Workentin, Mark S.
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p. 7239 - 7248
(2007/10/03)
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- Supercritical water oxidation of 2-chlorophenol effected by Li+ and CuO/zeolites
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Catalytic oxidation of 2-chlorophenol (2CP) in supercritical water was investigated. Experimentally, conversion of 2CP in supercritical water oxidation (SCWO) process is effectively enhanced in the presence of Li+ that also reduces the formation of higher chlorinated phenols and PAHs. The global reaction rate of SCWO of 2CP in the presence of Li+ is expressed as: 92.5 exp (-10.5/RT)[2CP]0.95[O2]0.56[H2O]0.45. The undesired by-products in the SCWO of 2CP are also extensively reduced in the channels of zeolite catalysts. By EXAFS spectroscopy, Cu-O and Cu-Cu are identified as the main oxidation active species in the zeolite channels. Cl-bonded CuO species in zeolite Y are not observed.
- Lin, Kuen-Song,Wang, H. Paul,Yang
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p. 1385 - 1396
(2007/10/03)
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- Synthesis of substituted 3′, 4′-dihyrospiro [indane-1, 2′(1′H) naphthalene]-1′-ols and their catalytic dehydrogenation
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Catalytic dehydrogenation of 5′, 7′-dimethyl-3′, 4′-dihydrospiro[indane-1, 2′(1′H) naphthalene]-1′-ol 5a, 7′-ethyl-3′,4′-dihydrospiro[indane-1, 2′-(1′H) naphthalene]-1′-ol 5b, 6-methyl-3′, 4′-dihydrospiro[indane-1, 2′(1′H) naphthalene]-1′-ol 5c and 6, 7′-dimethyl-3′, 4′-dihydrospiro[indane-1, 2′(1′H) naphthalene]-1′-ol 5d affords 1, 3-dimethylchrysene 6a, a mixture of 3-ethyl chrysene 6b and chrysene, 3-methylchrysene 6c and 3, 9-dimethylchrysene 6d, respectively. Condensation of anhydride of 1a of 1-carboxyindane-1-acetic acid with m-xylene and ethylbenzene give ketoacids 2a and 2b while 2c and 2d are obtained by condensation of the anhydride 1b of 1-carboxy-6-methylindane-1-acetic acid with benzene and toluene respectively. Catalytic reduction in acetic acid solution of 2a, 2c, 2d, and in ethanolic solution of 2b, give 3a, 3c, 3d and 3b. In ethanolic solution, 2c and 2d give esters 3cE and 3dE. Intramolecular acylation of 3a, 3b, 3c and 3cE and 3d and 3dE give 4a, 4b, 4c and 4d which after LAH reduction followed by dehydrogenation gave chrysenes 6a, 6b, 6c and 6d. Structures of all compounds corroborate their spectral data.
- Mitra, Ashutosh,Chowdhury, Mridula,Biswas, Tapan Kumar,Das, Sunil Baran
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p. 1120 - 1125
(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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- From phenylenes to acenes: Flash vacuum pyrolytic isomerization of angular [3]phenylene to benzo[ghi]fluoranthene
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The flash vacuum pyrolysis of angular [3]phenylene and bis(2-ethynylphenyl)ethyne produces benzo[ghi]fluoranthene and chrysene, respectively.
- Matzger, Adam J.,Vollhardt, K. Peter C.
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p. 1415 - 1416
(2007/10/03)
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- Complexation of aromatic hydrocarbons with a macrocycle containing four tropolone units in water
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The stability constants K of nine complexes formed from aromatic hydrocarbons and the macrocycle 1 in water were measured by the transport method (1H nmr spectroscopy was used in the case of benzene as guest). Their values increase with the number of aromatic rings in the aromatic hydrocarbons. A value of -1.5 Kcal mol-1 was obtained for the aromatic π-π interaction energy at 25°C.
- Poh, Bo-Long,Ng, Yian Yian
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p. 11913 - 11918
(2007/10/03)
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- Electrophotographic member
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Disclosed is an electrophotographic member containing as a charge transport material a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative which is remarkably excellent in solubility in an organic solvent and/or a binder such as polycarbonate resin, etc., can show very excellent electrophotographic properties such as high sensitivity, low residual potential and high durability. Further, a fluorine-containing N,N,N',N'-tetraarylbenzidine derivative usable as a charge transport material, and a process for producing the same are disclosed. Furthermore, a fluorine-containing diarylamine usable for producing the fluorine-containing N,N,N',N'-tetraarylbenzidine derivative, and a process for producing the same are disclosed.
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