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Benzene, Aromaticity, and Benzene Derivatives
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
In (c) Friedel–Crafts alkylation with the tertiary halide gives tert-butylbenzene (Section 16.2). Nitration of the activated ring gives the ortho- and para- nitro compounds (Section 16.2) and separation from the ortho- product allows isolation of the targeted product, 4-nitro-tert-butylbenzene.
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
High VOC concentrations were also found inside drycleaners. Total VOC concentrations during winter were 1135 µg/m3, 606.7 µg/m3, and 576.8 µg/m3 in D1, D2, and D3, respectively. Outdoors, it was 127.1 µg/m3, 78.2 µg/m3, and 64.3 µg/m3, respectively. The most abundant compound was toluene (480 µg/m3 during winter and 262 µg/m3 during summer). Additionally, chlorinated and brominated VOCs (carbon tetrachloride, bromoform, bromochloromethane, 1,2-bibromo-3-chloropropane, 1,1,1-trichloroethane), isopropyltoluene and 1,2,4-trimethylbenzene were found in high concentrations during both seasons. Although we did not evaluate PCE, the high abundance of toluene and chlorinated VOCs may be explained with the usage of reclaimed PCE, which include toluene, 1,1,1-trichloroethane and other chlorinated solvents, in dry cleanings (SCRD 2009). In the literature, PCE was studied in various dry cleaning establishments, and it was determined to be a dry cleaning-related VOC. Exposure to this VOC occurs when visiting drycleaners (D’Souza et al. 2009; Sherlach et al. 2011; Su et al. 2013). On the other hand, CTC is a common contaminant of indoor air and emitted from building materials or products (dry-cleaning agents, solvent, reagent in chemical synthesis, fire extinguisher fluid, fabric-spotting fluid, etc.) (Huang et al. 2014; USEPA 2010). Additionally, 1,1,1-TCA is used to clean leather and suede garments in dry cleaning (Doherty 2000). Elbir et al. (2007) also detected the significant contributions of 1,2,4-trimethylbenzene, propyl benzene, tert-butylbenzene, isoporopylbenzene and o,m-xylene possibly coming from a dry cleaning source.