Jia, Xuhong; Huang, Rui; Yang, Xiaoguang; Tao, Wan; Zhu, Xinhua published an article in 2021. The article was titled 《Synthesis and Characterization of a Novel Class of Zwitterionic Fluorocarbon Surfactants Based on Perfluorobutyl》, and you may find the article in Tenside, Surfactants, Detergents.Formula: C4H7BrO2 The information in the text is summarized as follows:
Perfluorooctane sulfonate (PFOS) and its derivatives had been banned due to their potential environmental hazards, although they possessed excellent surface activity. An effective method to solve this problem was to shorten the fluorocarbon chain of these surfactants from C8H17 to C4F9. As previous studies had shown, zwitterionic surfactants possess higher surface activity but have lower toxicity compared to other types of surfactants. In view of this, a class of novel zwitterionic fluorocarbon surfactants (n-CFNA-Br) with perfluorobutyl moiety was synthesized in this work. Their structures were characterized by FTIR, 1H NMR, 13C NMR, 19F NMR and MS. The results showed that all synthesized n-CFNA-Br had almost the same min. surface tension, but their critical micelle concentration (CMC) decreased with increasing length of hydrophobic carbon chain. In pure water, the surface tension at the CMC (γCMC) of the four n-CFNA-Br were about 20 mN/m, and the CMC values were 7.73 mmol/L for 1-CFNA-Br, 4.70 mmol/L for 2-CFNA-Br, 4.13 mmol/L for 3-CFNA-Br, and 3.36 mmol/L for 4-CFNA-Br, indicating high efficiency and effectiveness. In 0.1 mol/L NaCl, the CMC values reduced to less than half of the CMC values measured in the pure aqueous surfactant solution, while the surface tensions γCMC remained almost unchanged, indicating good salinity tolerance of the synthesized surfactants. The acidic surfactant solutions exhibited similar CMC values to the saline solutions, but the surface tension γCMC increased slightly to 25 mN/m. However, further investigation showed that the n-CFNA-Br surfactants exhibited poor surface activity in alk. solution (0.1 mol/L NaOH). In the pH range of 6.6 to 10.4, white precipitates appeared in the surfactant solutions after some time, indicating that the n-CFNA-Br are not suitable for use in alk. systems with pH greater than 6.6. In the experiment, the researchers used many compounds, for example, 4-Bromobutanoic acid(cas: 2623-87-2Formula: C4H7BrO2)
4-Bromobutanoic acid(cas: 2623-87-2) belongs to carboxylic acids. The chief chemical characteristic of the carboxylic acids is their acidity. They are generally more acidic than other organic compounds containing hydroxyl groups but are generally weaker than the familiar mineral acids (e.g., hydrochloric acid, HCl, sulfuric acid, H2SO4, etc.).Formula: C4H7BrO2
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary