CCl4 emissions in eastern China during 2021–2022 and exploration of potential new sources

Abstract

According to the Montreal Protocol, the production and consumption of ozone-layer-depleting CCl4 for dispersive applications was globally phased out by 2010, including China. However, continued CCl4 emissions were disclosed, with the latest CCl4 emissions unknown in eastern China. In the current study, based on the atmospheric measurements of ~12,000 air samples taken at two sites in eastern China, the 2021–2022 CCl4 emissions are quantified as 7.6 ± 1.7 gigagrams per year. This finding indicates that CCl4 emissions continued after being phased out for dispersive uses in 2010. Subsequently, our study identifies potential industrial sources (manufacture of general purpose machinery and manufacture of raw chemical materials, and chemical products) of CCl4 emissions.

Site-Selective Photobromination of O-Acetylated Carbohydrates in Benzotrifluoride

“…Accordingly, the Ferrier photobromination mirrors the Wohl-Ziegler bromination of benzylic and allylic substrates across mechanistic and practical aspects. , The major limitation of these reactions, however, is their dependency on CCl 4 as a solvent. CCl 4 is a hepatotoxic and ozone-depleting substance which was banned from commercial production and sale under the 1994 Montreal Protocol . Unfortunately, while multiple sets of CCl 4 -free conditions have been sourced for the Wohl-Ziegler bromination, a single, versatile substitute compatible with the Ferrier photobromination has yet to be identified. − It can also be considered that commercial heat lamps, which inherently vary by their luminous flux (Φ v ) and emission wavelength (λ) ranges, introduce great concerns for reproducibility across studies.…”