The Krafft temperatures, surface tensions and bacteriostatic efficacies of a series of dodecyl/tetradecyltrimethylammonium salts with new type counterions based on the general formula RN+(CH3)3 A− were measured. The results revealed that the Krafft temperatures of the studied products were below 0 °C and the surface tensions of water were decreased to 22–42 mN m−1 when applying these surfactants at a concentration range from 10−2 to 10−4 mol L−1. Moreover, the physicochemical parameters such as the saturation adsorption value, the minimum area per surfactant molecule and the standard thermodynamic parameters of adsorption and micellization varied with different counterions for these prepared quaternary ammonium salts. In addition, the bacteriostatic tests showed that the counterions with shorter carbon chain lengths were associated with greater efficacy for the novel quaternary ammonium salts studied here.
To accurately describe the adsorption equilibria of N 2 and O 2 on LiLSX zeolite in the design of air separation by pressure swing adsorption, an applicable model (aNRTL−RAST) was developed. It was based on the real adsorbed solution theory (RAST) in which the activity coefficient was calculated by the nonrandom two-liquid theory (aNRTL). The binary adsorbate− adsorbate interaction parameters of the aNRTL theory were estimated from the pure component isotherms. The aNRTL−RAST model was used to predict the mixed gas equilibrium data under different adsorption conditions and compared with the extended Langmuir (E-L), two-dimensional equation of state (2D-EOS), and ideal adsorbed solution (IAST) models. aNRTL−RAST showed better accuracy than the other models, and the average errors for different adsorption conditions were <5%. Therefore, this model can be used to predict the adsorption equilibrium of mixed gases, avoiding complicated and tedious experiments. This study provides a theoretical basis for the selection of oxygen adsorbents for the separation process design of industrial air separation.
A series of catanionic surfactants based on the general formula CH3CH2(CH2)11CH2N+(CH3)3 · −OOCCH2(CH2)nCH2CH3 (n = 2, 4, 6, 8, 10) were synthesized, and measured their critical micelle concentrations (CMC) and the corresponding surface tension at CMC (γCMC). The results revealed that the surface tensions of water were decreased to 21–34 mN · m−1 when applying these surfactants at a concentration range from 10−3 to 10−4 mol · L−1. Moreover, the performance of foaming, emulsification, anti-static and rewetting of the surfactants were investigated and the results showed that both the rewetting and emulsifying ability of the prepared surfactants were much better than that of conventional surfactants. In addition, the anti-static and foaming properties were also improved at the same condition compared to that of conventional surfactants.
A series of tetradecyltrimethylammonium carboxylates based on the general formula-CH 3 (CH 2 ) 12 CH 2 N þ (CH 3 ) 3 Á -OOCCH 2 (CH 2 ) n CH 2 CH 3 (n ¼ 4, 6, 8) were synthesized. The tetradecyldimethylamines were quaternized with dimethyl carbonate, followed by reaction with different carboxylic acids to prepare the tetradecyltrimethylammonium carboxylates, and their structures were characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The critical micelle concentration and the minimum surface tension of these surfactants were also studied. The results indicated that the prepared surfactants could reduce the surface tension of water to 21-26 mN/m at concentration levels of 10 À4 mol/L. Furthermore, their wetting ability and emulsifying ability were also investigated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.