- REDUCTIVE RING CLOSURE OF HELICENES
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Reduction of -helicene (1) by alkali metal in THF yields a closed condensed polycyclic dianion i.e. benzoperylene dianion (3=).The ring closure reaction takes place via dihydro intermediate (2=).
- Ayalon, Ari,Rabinovitz, Mordecai
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Read Online
- Probing Diels-Alder reactivity on a model CNT sidewall
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We have synthesized a cycloparaphenylene containing a perylene motif that is a model for a carbon nanotube sidewall. The reactivity of the sidewall model towards a Diels-Alder reaction using a masked acetylene was examined and similar reactivity was observed between the macrocyclic and planar substrate. This study suggests that a Diels-Alder reaction is a viable method for carbon nanotube growth using an appropriate template.
- Jackson, Evan P.,Sisto, Thomas J.,Darzi, Evan R.,Jasti, Ramesh
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Read Online
- ORGANIC COMPOUND, THREE-DIMENSIONAL ORGANIC FRAMEWORK FORMED BY USING ORGANIC COMPOUND, SEPARATION SIEVE AND OPTICAL LAYER, WHICH COMPRISE ORGANIC FRAMEWORK, AND OPTICAL DEVICE COMPRISING OPTICAL LAYER AS OPTICAL AMPLIFICATION LAYER
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An organic compound, a three-dimensional organic structure formed by using the organic compound, a separation sieve and an optical layer having the organic structure, and an optical device having the optical layer as an optical amplification layer are provided. The organic structure includes a plurality of organic molecules self-assembled by non-covalent bonding. Each of the unit organic molecules has an aromatic ring, a first pair of substituents being connected to immediately adjacent positions of substitutable positions of the aromatic ring, and a second pair of substituents being connected to immediately adjacent positions of remaining substitutable positions of the aromatic ring. The unit organic molecules are self-assembled by van der Waals interaction, London dispersion interaction or hydrogen bonding between the first and the second pairs of the substituents and by pi-pi interactions between the aromatic rings.
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Paragraph 0356; 0359; 0360
(2019/02/13)
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- Organic compound and 3-dimensional organic framework formed using the same
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Provided is a three-dimensional organic framework. The organic framework comprises a plurality of organic molecules which are self-assembled by non-covalent bonds. Each of the organic molecules comprises: a first pair of substituents which are each bound to an aromatic ring and to immediately adjacent positions among substitutable positions of the aromatic ring; and a second pair of substituents which are each bound to immediately adjacent positions among the rest of the substitutable positions. The organic molecules are self-assembled through Van Der Waals interactions, London dispersion interactions, or hydrogen bonding between the first and second pairs of the substituents, and andpi;-andpi; interactions between the aromatic rings.COPYRIGHT KIPO 2018
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Paragraph 0321; 0325; 0326
(2018/07/07)
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- Facile photochemical synthesis of 5,10-disubstituted [5]helicenes by removing molecular orbital degeneracy
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Photocyclodehydrogenation is a key reaction to synthesize helicenes; however, because of overannulation, it is not applicable to the synthesis of [5]helicene. Introduction of a cyano group was found to remove the orbital degeneracy of the low-lying unoccupied MOs; consequently, the lowest excitation comprises a single transition involving the C2-antisymmetric MO. Therefore, the problematic overannulation can be effectively suppressed. Moreover, in combination with the Knoevenagel reaction, a one-pot synthesis of 5,10-dicyano[5]helicene with 67% yield was accomplished.
- Ito, Natsuki,Hirose, Takashi,Matsuda, Kenji
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supporting information
p. 2502 - 2505
(2014/05/20)
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- Synthesis of [5]helicenes with a substituent exclusively on the interior side of the helix by metal-catalyzed cycloisomerization
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[5]Helicenes with a substituent exclusively oriented toward the interior curvature of the helix are synthesized by metal-catalyzed cycloisomerization. In addition, novel azulene-fused helicenes have been found through cycloisomerization studies. These [5]helicenes shows a high enough configurationally stability to allow resolution by HPLC on a chiral stationary phase.
- Yamamoto, Kosuke,Okazumi, Mieko,Suemune, Hiroshi,Usui, Kazuteru
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supporting information
p. 1806 - 1809
(2013/06/04)
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- Benzannulated cycloheptanones from binaphthyl platforms
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Preparations of benzannulated cycloheptanones starting from unique binaphthyl molecular platforms are described. Binaphthyl acetic acids proved suitable percursors for fused cycloheptanone architectures. Seven-membered rings embedded in binaphthyl units were selectively generated by use of Eaton's reagent. Isomeric helical architectures arising from electrophilic cyclisation processes at second reaction sites in the precursors could also be obtained under different acidic conditions. Unambiguous discrimination between isomeric geometries was provided by multiple quantum NMR sequences. DFT calculations were performed and gave evidence of different behaviour of the substrates towards intramolecular electrophilic substitution. The theoretical approach confirmed the experimental results, agreeing completely with X-ray data. Preparations of benzannulated cycloheptanones starting from binaphthyl molecular platforms are described. Copyright
- Pieters, Gregory,Sbargoud, Kamal,Bridoux, Alexandre,Gaucher, Anne,Marque, Sylvain,Bourdreux, Flavien,Marrot, Jerome,Flot, David,Wantz, Guillaume,Dautel, Olivier,Prim, Damien
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supporting information
p. 490 - 497
(2013/02/25)
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- Fluorescent coronene monoimide gels via H-bonding induced frustrated dipolar assembly
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Two stage self-assembly of novel coronene monoimide (CMI) based gels that results in resurfacing of monomer emission in the aggregated state is reported. This process is attributed to a frustrated head-head dipolar assembly forced by hydrogen bonding.
- Jain, Ankit,Rao, K. Venkata,Kulkarni, Chidambar,George, Anjana,George, Subi J.
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supporting information; scheme or table
p. 1467 - 1469
(2012/03/11)
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- Expeditious synthesis of helicenes using an improved protocol of photocyclodehydrogenation of stilbenes
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An improved procedure has been developed for photodehydrocyclization of stilbenes for the synthesis of phenanthrenes and helicenes. This procedure involves the use of THF as a scavenger of hydriodic acid produced during iodine mediated photodehydrocyclization. The use of THF is advantageous due to its higher boiling point, lower cost and easy availability as compared to propylene oxide. The method is applied to synthesize a number of phenanthrenes and helicenes. ARKAT-USA, Inc.
- Talele, Harish R.,Chaudhary, Anju R.,Patel, Parthiv R.,Bedekar, Ashutosh V.
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experimental part
p. 15 - 37
(2011/06/19)
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- One-step conversion of aromatic hydrocarbon bay regions into unsubstituted benzene rings: A reagent for the low-temperature, metal-free growth of single-chirality carbon nanotubes
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A tube ride: The controlled chemical synthesis of uniform, single-walled carbon nanotubes from short hydrocarbon templates, such as aromatic belts and geodesic nanotube end-caps, by a Diels-Alder cycloaddition/rearomatization strategy requires a potent masked acetylene capable of transforming hydrocarbon bay regions into new unsubstituted benzene rings in a single operation. Nitroethylene has been found to effect such benzannulations (see scheme).
- Fort, Eric H.,Scott, Lawrence T.
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supporting information; experimental part
p. 6626 - 6628
(2010/10/21)
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- Synthesis of derivatives of phenanthrene and helicene by improved procedures of photocyclization of stilbenes
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An improved method has been developed for photocyclization of stilbene to construct phenanthrenes and benzo[c]phenanthrenes. This reaction is promoted by iodine while tetrahydrofuran is used as an efficient and inexpensive scavenger of hydroiodic acid produced during the photocyclization sequence. In another process, cyclohexene is used as a reagent for dehydrogenation step in place of THFI2.
- Talele, Harish R.,Gohil, Monik J.,Bedekar, Ashutosh V.
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scheme or table
p. 1182 - 1186
(2009/12/25)
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- Organic Silane Compound, Method of Producing the Same, and Organic Thin Film Using the Same
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The present invention provides a highly ordered, crystallized organic thin film superior in electroconductive properties that is resistant to exfoliation, a compound for preparation of the thin film, and a method of producing the same. An organic silane compound, characterized in that a molecule represented by General Formula (I) is substituted with a silyl group. A method of producing the organic silane compound, comprising halogenating a molecule (I) and allowing it to react with a silane derivative. An organic thin film, wherein the organic silane compound molecule is oriented with its silyl group located in the substrate side and the molecule (I) region in the film surface side. (wherein, x1 and x2 are integers satisfying 1≦x1, 1≦x2, and 2≦x1+x2≦8; each of y1 and z1 is independently an integer of 2 to 8; each of y2 and z2 is independently an integer of 0 to 8; and the skeleton may be substituted with a hydrophobic group).
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Page/Page column 6-7
(2009/01/24)
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- Thermal cyclodehydrogenations to form 6-membered rings: Cyclizations of [5]helicenes
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Flash vacuum pyrolysis (FVP) of [5]helicene induces a thermal cyclodehydrogenation to form benzo[ghi]perylene. Evidence is presented that supports an electrocyclization-rearomatization mechanism and is inconsistent with mechanistic alternatives involving the intermediacy of aryl radicals or carbenes in the helicene fjord region.
- Xiang, Xue,Scott, Lawrence T.
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p. 3937 - 3940
(2008/02/11)
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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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- 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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- Semivolatile and volatile compounds in combustion of polyethylene
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The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
- Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
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p. 615 - 627
(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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- Analysis of hydrocarbons and ash particles formed from contaminated industrial biowaste under combustion-like conditions
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A concept of multizone combustion of pulp and paper-generated biowaste was investigated. The biowaste was initially fed into the low-temperature region (1250 K) and then subjected to the high-temperature treatment (1770 K), which was followed by sudden quenching in a second lowtemperature zone (1250 K). This type of burning is called the low-high-low temperature process (LHL). It was found that destruction of selected polycyclic aromatic compounds occurred during the LHL process before they were emitted into the atmosphere. The biowaste material underwent dramatic morphological changes, which influenced segregation of metals within ash particles and their leachability. The heavy metals (Cr, Cd, Pb) were encapsulated and immobilized within the ash particle core surrounded by a compact shell consisting of condensed layers of light nonhazardous metals (Si, Al, Na, K). It seems that the multizone combustion of biowaste may be an attractive and useful way for the clean and efficient disposal of contaminated biowastes.
- Kozinski, Janusz A.,Zheng, Guohui,Uloth, Vic,Gangli, Peter,Hutny, Wes
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p. 4318 - 4325
(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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- BROMINE AUXILIARIES IN PHOTOSYNTHESES OF HELICENES
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Bromine substituents on benzene rings direct photocyclizations away from their ortho positions.This principle prevents helicenes from photocyclizing and methoxyls from photoeliminating.It makes possible the photosynthesis of helicene and of a tetramethoxy-derivative of helicene.
- Liu, Longbin,Katz, Thomas J.
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p. 6831 - 6834
(2007/10/02)
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- An Unusual Fluorine Atom Rearrangement in the Photocyclization of 1-Fluorohelicenes
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Oxidative photocyclization of 1-fluorohelicene and two of its chlorine-substituted derivatives leads to the formation of 8-fluorobenzoperylenes through an unprecedented inter-ring fluorine atom migration; photoelimination of HF to give benzoperylenes also occurs as a competing process.The rearrangement pathway predominates when the irradiation is carried out at 0 deg C in air-saturated benzene solution containing 10 -3 M iodine; the elimination pathway predominates at higher temperatures or in the absence of either oxygen or iodine.The rearrangement isrationalized by postulating a triplet-state photocyclization to give a dihydrobenzoperylene intermediate, followed by abstraction of the tertiary hydrogen atom from that intermediate to give a radical that subsequently undergoes a fluorine atom shift by an SNi'mechanism.
- Mallory, Frank B.,Mallory, Clelia W.
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p. 526 - 532
(2007/10/02)
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- Determination of Rate Constants for Electron Transfer from Radical Anions of Aromatic Compounds to Diaryl Disulfides
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Rate constants for electron transfer from the radical anions of aromatic compounds to diaryl disulfides (ArSSAr) have been determined in tetrahydrofuran.By the change of the reduction potentials of the aromatic compounds from -1.04 to -1.91 V (vs.SCE), the rate constants varied from 0.015 to 2.3 * 108 M-1 s-1; conventional spectrophotometry has been employed to measure the slow reaction rates, and the xenon-flash photolysis technique has been applied to the fast reaction systems.The reaction including the free ion or the loose ion pair of the thioxanthone sulfone radical anion, (TO-SO2)-/., was faster than that including the tight ion pair.In the case of the (TO-SO2)-/., Na+-PhSSPh system, temperature variation yielded the free energy of activation (ΔG* = 18.7 kcal/mol) and activation enthropy (ΔS* = -29.1 eu) at 22.4 deg C; the reduction potential of PhSSPh was estimated to be -1.80 V vs.SCE from ΔG* value.Electron-withdrawing substituents of ArSSAr increase the rates and vice versa; the Hammett reaction constants (ρ) were estimated to be ca. +1.50 and 1.40 for electron transfer from perylene radical anion and (TO-SO2)-/.,Na+ to ArSSAr, respectively.The factors controlling the rates have been examined.
- Tagaya, Hideyuki,Aruga, Tamotsu,Ito, Osamu,Matsuda, Minoru
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p. 5484 - 5489
(2007/10/02)
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