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Atomic, Molecular, and Optical Physics
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Name Cyanogen chloride Dichloromethylene Dichlorodifluoromethane Carbonyl chloride Trichlorofluoromethane Tetrachloromethane Fluoromethylidyne Cyanogen fluoride Difluoromethylene Carbonyl fluoride Trifluoromethyl Trifluoroiodomethane Methylidyne Bromodichloromethane Chlorodibromomethane Tribromomethane Chloromethylene Chlorodifluoromethane Dichlorofluoromethane Trichloromethane Fluoromethylene Trifluoromethane Triiodomethane Hydrogen cyanide Hydrogen isocyanide Isocyanic acid Fulminic acid Oxomethyl (HCO) Methylene Bromochloromethane Dibromomethane Chlorofluoromethane Dichloromethane Difluoromethane Diiodomethane Diazomethane Cyanamide Formaldehyde Formic acid Methyl Borane carbonyl Bromomethane Chloromethane Methyltrichlorosilane Fluoromethane Iodomethane Formamide Nitromethane Methyl azide Methoxy Methane Urea Methanol Methanethiol Methylamine Methylhydrazine Methylsilane Cyanide Cyanate Carbon monoxide
Chemicals in California Drinking Water: Source of Contamination, Risk Assessment, and Drinking Water Standards
Published in Rhoda G.M. Wang, Water Contamination and Health, 2020
Richard H. F. Lam, Joseph P. Brown, Anna M. Fan
One major issue of concern with regard to the use of Delta water for drinking is the formation of trihalomethanes. THM are formed when certain organic substances dissolved in the water combine with chlorine used to disinfect drinking water. The most common THM compounds formed during chlorination include chloroform, bromodichloromethane, chloro-dibromomethane, and bromoform. With the exception of chlorodibro-momethane (placed in group C), the other THM compounds are classified by the U.S. EPA as probable human carcinogens (group B2). All four
Chemistry of the Poly(alkylene oxide)s
Published in F. E. Bailey, Joseph V. Koleske, Alkylene Oxides and Their Polymers, 2020
F. E. Bailey, Joseph V. Koleske
Craven and coworkers (17) prepared ethylene oxide/oxy- methylene block copolymers by means of a modified Williamson ether synthesis (18). Low-molecular-weight (-200) polyoxyethylenes were reacted with dibromomethane in the presence of potassium hydroxide in chlorobenzene solvent.
Restricted substances for textiles
Published in Textile Progress, 2022
Arun Kumar Patra, Siva Rama Kumar Pariti
Regarding polybrominated diphenyl ethers (PBDE), they are effective flame retardants and are produced by bromination of diphenyl ether in the presence of a Friedel-Craft catalyst (i.e., AlCl3) in a solvent such as dibromomethane. Diphenyl ether molecules contain 10 hydrogen atoms, any of which can be exchanged with bromine, resulting in 209 possible congeners, wherein minor compounds other than ethanol are formed (Alaee et al., 2003). Among the three products in this category, deca-bromodiphenyl ether (DBDE) has occupied the larger market share worldwide. It exists as a relatively-pure mixture containing more than 97% of DBDE itself, less than 3% of nonabromodiphenyl ether (NBDE) and a very small proportion of octaBDE. Other than textiles, DBDE also finds use as an additive flame-retardant in electrical and electronic equipment. Commercial octabromodiphenyl ether (OBDE) is a somewhat complex mixture containing only 31%–35% OBDE itself, 10%–12% hexabrominated diphenyl ether (HxBDE), 44% heptaBDE, 10%–11% NBDE and less than 1% DBDE. Its application is limited to ABS resin. Both DBDE and OBDE are available in white powder form while the third variant, pentabrominated diphenyl ether (PBDE) is a viscous liquid mainly used in textiles as an additive in polyurethane foams, but it also has some use in phenolic resins, polyesters and epoxy resins (Linda & Staskal, 2004). Commercial penta mixtures contain 50 to 60% of PBDE but its use has been substantially decreased due to a voluntary ban in Europe.
A comprehensive review on water stable metal-organic frameworks for large-scale preparation and applications in water quality management based on surveys made since 2015
Published in Critical Reviews in Environmental Science and Technology, 2022
R. Y. Li, Z. S. Wang, Z. Y. Yuan, Constance Van Horne, Viatcheslav Freger, M. Lin, R. K. Cai, J. P. Chen
Washing MOFs with organic solvents is the traditional method for purification (Woodliffe et al., 2021). Additionally, several solid separation techniques are also used and described in the literature. These solid separation techniques are based on the physical properties of MOFs and solid impurities, such as particle sizes and densities (Keene et al., 2011). These techniques include centrifugation, settling, hydro-cyclone, filtration, sonication, froth separation, flow separation, and density separation technologies. For example, the mixture of brominated solvents like dibromoethane, bromoform, and dibromomethane with densities from 1.48 to 2.89 g cm-3 is usually used for MOF particle separation based on the difference in densities (Keene et al., 2011). However, a key challenge remains, as the densities of MOFs are similar to those of solid impurities (Rubio-Martinez et al., 2017).
Volatile organic compound concentrations and their health risks in various workplace microenvironments
Published in Human and Ecological Risk Assessment: An International Journal, 2020
Simge Çankaya, Hakan Pekey, Beyhan Pekey, Burcu Özerkan Aydın
Determination of the I/O ratios of VOC concentrations in each microenvironment is important so that the dominant environment can be determined. Therefore, the mean I/O ratios during each season were calculated (Table 6). The mean concentrations of 1,1,1-trichloroethane, 1,2-dichloropropane, toluene, styrene, sec-butylbenzene, and hexachlorobutadiene were higher indoors than outdoors in all microenvironments during both seasons. Generally, indoor concentrations of 24 VOCs were higher during winter than summer. The I/O ratios of VOCs detected in this study can be divided into three categories: primarily outdoor sources (I/O < 1.5), both indoor and outdoor sources (1.5 ≤I/O ≤ 10), and primarily indoor sources (I/O > 10) (USEPA 1999). The I/O ratios of trans-1,2-dichloroethylene ranged from 0.52 to 1.14, indicating that the source was primarily outdoors (Xu et al.2016). Additionally, bromochloromethane, CTC, dibromomethane, bromodichloromethane, and chlorobenzene detected at auto paint shops were primarily from outdoor sources because the I/O ratios were low (<1.5). Chlorobenzene and xylenes detected in restaurants also had primarily outdoor sources as did benzene detected at dry cleaners and photocopy centers. The I/O ratios of some VOCs were greater than 10 in some microenvironments. Examples at dry cleaners are isopropyl toluene, isopropyl benzene, sec-butylbenzene, and hexachlorobutadiene during both winter and summer and toluene in winter. This implies that these compounds had primarily indoor sources. Other VOCs had both indoor and outdoor sources.