34244-14-9Relevant articles and documents
Seasonal variability of 1-chloropyrene on atmospheric particles and photostability in toluene
Ohura, Takeshi,Kitazawa, Atsushi,Amagai, Takashi
, p. 831 - 837 (2004)
The occurrence of a mutagenic compound, 1-chloropyrene (Cl-Py), in extracts of ambient particulate matter at an urban site in Japan has been investigated. Samples were collected with a high-volume air sampler for 24 h periods over the course of 1 week in winter (February), spring (May), summer (August), and autumn (November) 2002. The Cl-Py levels showed seasonal variation, ranging from 2.4 pg/m3 (summer) to 18.9 pg/m3 (winter). This variation would indicate that the lower temperatures in winter results in an increased distribution of Cl-Py from vapor phase to the particle phase. In addition, there is also the possibility that ambient Cl-Py is emitted from seasonal sources or is susceptible to photodegradation by sunlight, or both. The photodegradation of Cl-Py in a laboratory experiment was conducted to simulate the compound's fate on airborne particle surfaces. The degradation of Cl-Py proceeded by a first-order reaction with a rate constant of 0.72 h-1. In the presence of a radical sensitizer, 9,10-anthraquinone (AQ), the photodegradation rate of Cl-Py was elevated in comparison with the rate in the absence of AQ. In addition, the dechlorination of Cl-Py (i.e., the formation of Py) occurred in the presence of AQ.
Oxidative Photochlorination of Electron-Rich Arenes via in situ Bromination
Düsel, Simon Josef Siegfried,K?nig, Burkhard
supporting information, p. 1491 - 1495 (2019/04/30)
Electron-rich arenes are oxidatively photochlorinated in the presence of catalytic amounts of bromide ions, visible light, and 4CzIPN as organic photoredox catalyst. The substrates are brominated in situ in a first photoredox-catalyzed oxidation step, followed by a photocatalyzed ipso-chlorination, yielding the target compounds in high ortho/para regioselectivity. Dioxygen serves as a green and convenient terminal oxidant. The use of aqueous hydrochloric acid as the chloride source reduces the amount of saline by-products.
Mechanistic studies into amine-mediated electrophilic arene borylation and its application in MIDA boronate synthesis
Bagutski, Viktor,Del Grosso, Alessandro,Carrillo, Josue Ayuso,Cade, Ian A.,Helm, Matthew D.,Lawson, James R.,Singleton, Paul J.,Solomon, Sophia A.,Marcelli, Tommaso,Ingleson, Michael J.
supporting information, p. 474 - 487 (2013/02/25)
Direct electrophilic borylation using Y2BCl (Y2 = Cl2 or o-catecholato) with equimolar AlCl3 and a tertiary amine has been applied to a wide range of arenes and heteroarenes. In situ functionalization of the ArBCl2 products is possible with TMS 2MIDA, to afford bench-stable and easily isolable MIDA-boronates in moderate to good yields. According to a combined experimental and computational study, the borylation of activated arenes at 20 C proceeds through an S EAr mechanism with borenium cations, [Y2B(amine)] +, the key electrophiles. For catecholato-borocations, two amine dependent reaction pathways were identified: (i) With [CatB(NEt 3)]+, an additional base is necessary to accomplish rapid borylation by deprotonation of the borylated arenium cation (σ complex), which otherwise would rather decompose to the starting materials than liberate the free amine to effect deprotonation. Apart from amines, the additional base may also be the arene itself when it is sufficiently basic (e.g., N-Me-indole). (ii) When the amine component of the borocation is less nucleophilic (e.g., 2,6-lutidine), no additional base is required due to more facile amine dissociation from the boron center in the borylated arenium cation intermediate. Borenium cations do not borylate poorly activated arenes (e.g., toluene) even at high temperatures; instead, the key electrophile in this case involves the product from interaction of AlCl3 with Y2BCl. When an extremely bulky amine is used, borylation again does not proceed via a borenium cation; instead, a number of mechanisms are feasible including via a boron electrophile generated by coordination of AlCl3 to Y2BCl, or by initial (heteroarene)AlCl3 adduct formation followed by deprotonation and transmetalation.
Behavior and prediction of photochemical degradation of chlorinated polycyclic aromatic hydrocarbons in cyclohexane
Ohura, Takeshi,Amagai, Takashi,Makino, Masakazu
, p. 2110 - 2117 (2008/09/19)
The photochemical degradation of 11 chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and the corresponding 5 parent PAHs was examined to simulate the compound's fate on aerosol surfaces. All the ClPAHs and PAHs decayed according to the first-order reaction rate kinetics. The photolysis rates of ClPAHs varied greatly according to the skeleton of PAHs; the rates of chlorophenanthrenes (ClPhes) and 1-chloropyrene were higher than those of corresponding parent PAHs, whereas chlorofluoranthenes, 7-chlorobenz[a]anthracene and 6-chlorobenzo[a]pyrene were more stable under irradiation compared to respective parent PAH. Considering the photoproducts of ClPhes detected, the oxidation could occur immediately at positions of the highest frontier electron density. Finally, the quantitative structure-property relationship models were developed for direct photolysis half-lives and average quantum yields of the ClPAHs and parent PAHs, in which the significant factors affecting photolysis were ELUMO+1, total energy and surface area, and ELUMO, ELUMO - EHOMO and total energy, respectively.
Reaction of polycyclic aromatic hydrocarbons adsorbed on silica in aqueous chlorine
Nakamura, Hideyuki,Tomonaga, Yuzo,Miyata, Kana,Uchida, Mitsuo,Terao, Yoshiyasu
, p. 2190 - 2195 (2007/10/03)
The reaction of polycyclic aromatic hydrocarbons (PAHs) previously adsorbed on silica gel or diatomaceous earth with sodium hypochlorite was carried out to elucidate their reactivity to aqueous chlorine. It was demonstrated that the PAHs adsorbed on silica reacted more rapidly than the PAHs themselves in water, leading to the formation of many chlorinated and oxidized derivatives. A similar reaction in the presence of potassium bromide was found to preferentially produce corresponding brominated derivatives. These reactions seem to proceed through PAHs adsorbed on the silica surface and halogenating agents, the electrophilicity of which may be raised by the catalytic effect of the silanol group of the silica surface. These findings from the environmental viewpoint suggest that the reaction of hydrophobic compounds adsorbed on sediment cannot be neglected.
SURFACE PHOTOCHEMISTRY: THE PHOTO-CHLORINATION OF AROMATIC HYDROCARBONS WITH FERRIC CHLORIDE ON ALUMINA
Hasebe, Masato,Lazare, Catherine,Mayo, Paul de,Weedon, Alan C.
, p. 5149 - 5152 (2007/10/02)
Irradiation of a number of aromatic hydrocarbons adsorbed on alumina in the presence of ferric chloride leads to monochlorination.
