The author of 《Photochemical degradation of polyhalogenated carbazoles in hexane by sunlight》 were Zhou, Shanshan; Pan, Xiaoxue; Tang, Qiaozhi; Zhu, Hongbin; Zhou, Jiayi; Zhao, Lu; Guo, Jiehong; Wang, Zunyao; Liu, Weiping; Li, An. And the article was published in Science of the Total Environment in 2019. Quality Control of 3,6-Dibromo-9H-carbazole The author mentioned the following in the article:
Polyhalogenated carbazoles (PHCZs) are a class of halogenated dibenzopyrrole, which have been increasingly detected in the environment and found to be bioaccumulative and potentially toxic. However, their environmental transformation potential is largely unknown. In this study, UV absorption spectra of carbazole (CZ) and 10 PHCZs were obtained with wavelength range 290-400 nm, and three peaks were identified in most cases with the highest occurring around 300 nm. Hexane solutions of CZ, 10 individual PHCZs, and a sediment extract containing nine other PHCZs were sep. irradiated under natural sunlight in order to investigate their photodegradation kinetics and pathways. The pseudo-first-order reaction rate constants (k) of these PHCZs varied from 0.183 h-1 to 2.394 h-1, and increased exponentially with increasing numbers of chlorines and bromines in PHCZ mols. Contribution to ln k from each bromine atom is more than doubling of that from each chlorine atom. Stepwise reduction debromination was confirmed to be one of the photodegradation mechanisms for both brominated and mixed halogenated (containing both bromine and chlorine) carbazoles. Only sporadic dechlorinated products were found during the photolysis of chlorinated carbazoles. By adopting a simplified kinetic approach, we estimated that dehalogenation contributed approx. 20% to 51% of the total loss of the parent PHCZs. In the experiment, the researchers used 3,6-Dibromo-9H-carbazole(cas: 6825-20-3Quality Control of 3,6-Dibromo-9H-carbazole)
3,6-Dibromo-9H-carbazole(cas: 6825-20-3) is used as a pharmaceutical intermediate, and also an important intermediate of synthesizing optoelectronic materials. It has been used in the preparation of N-(2-hydroxyethyl)-3,6-dibromocarbazole.Quality Control of 3,6-Dibromo-9H-carbazole
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary