21948-96-9Relevant articles and documents
Salt effects on the aqueous two-phase system of Gemini(12-3-12, 2Br -)/SDS/PEG
Al-Hakimi, Abdulaziz Mohammed,Shang, Yazhuo,Liu, Honglai,Hu, Ying
, p. 1307 - 1313 (2009)
The effect of added salts (NaCl, KCl and NaBr) on the aqueous two-phase system (ATPS) formed in mixtures of Gemini(12-3-12, 2Br-)/sodium dodecyl sulfate/polyethylene glycol has been investigated. Phase diagrams of the aqueous systems containing Gemini(12-3-12, 2Br-), sodium dodecyl sulfate (SDS), polyethylene glycol(PEG) and a salt have been determined experimentally at 313.15 K. The results indicate that the addition of salts not only induces the appearance of ATPS-A (in which anionic surfactant is in excess), shortens the phase separation time, enlarges the regions of ATPS-C (in which cationic surfactant is in excess), and decreases the minimum concentration required for forming an ATPS, but also alters the matching between anionic and cationic surfactants. Extractive experiments also showed that these salts notably enhance the extraction ability of ATPS; the Gemini-rich phase exhibits prominent cohesive action with xylenol orange, regardless of whether or not it is the upper phase or the lower phase.
First evaluation of the thermodynamic properties for spheres to elongated micelles transition of some propanediyl-α,ω-bis(dimethylalkylammonium bromide) surfactants in aqueous solution
Fisicaro, Emilia,Compari, Carlotta,Duce, Elenia,Contestabili, Cristina,Viscardi, Guido,Quagliotto, Pieriuigi
, p. 1744 - 1749 (2005)
The apparent and partial molar enthalpies, apparent molar volumes, and adiabatic compressibilities at 298 K of the aqueous solutions of the cationic gemini surfactants propanediyl-α,ω-bis(octyldimethylammonium bromide) (8-3-8) and propanediyl-α,ω-bis(dodecyldimethylammonium bromide) (12-3-12) have been measured as a function of concentration. The trends of the partial molar enthalpies versus concentration are the first well documented thermodynamic evidence of sphere to rod transition in the micellar phase, involving a detectable quantity of heat, and allow the determination of the change in enthalpy associated with this transition. The changes in enthalpies upon micellization and for the sphere to elongated micelles transition, ΔHs-r have been obtained from the experimental data by using a pseudo-phase transition approach: -1.5 kJ mol-1 for 8-3-8 and -3.9 kJ mol-1 for 12-3-12. No evidence of the above transition is found in the trends of volumetric properties versus m. The apparent adiabatic molar compressibilities for the compounds under investigation are also reported here for the first time: a negative group contribution for the methylene group is evaluated, when the surfactants are present in solution as a single molecule, reflecting its solvation structure. In the micellar phase, the -CH2- group contribution becomes positive. A value of 1.17 × 10-3 cm3 bar-1 mol-1 for the change in adiabatic molar compressibility upon micellization is obtained. The lower values of the methylene group contributions to the volumetric properties for the monomers support the hypothesis of partial association of the chains before the cmc.
Gemini surfactants foam formation ability and foam stability depends on spacer length
Kuliszewska, Edyta,Brecker, Lothar
, p. 951 - 957 (2014/11/08)
A series of cationic gemini surfactants containing different spacer length were synthesized and analyzed structurally. It was shown that the surface tension (σ) and critical micelle concentration (CMC), which had a maximum for the n-C4H8 spacer depended on the spacer length. The foaming ability and foam stability are high for the gemini surfactants with short spacers (C2H4 to n-C4H8), while longer spacers lead to a distinct decrease of these foam parameters. Foaming properties are discussed in terms of configuration and conformation of a surfactant molecule and in relation to micellization state kinetic.
Synthesis, molecular structure, spectral properties and antifungal activity of polymethylene-α,ω-bis(n,n-dimethyl-n-dodecyloammonium bromides)
Brycki, Bogumil,Kowalczyk, Iwona,Kozirog, Anna
experimental part, p. 319 - 335 (2011/04/18)
Hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (1), pentamethylene-1,5-bis(N,N-dimethyl-N-dodecylammonium bromide) (2), tetramethylene-1,4-bis(N,N-dimethyl-N-dodecylammonium bromide) (3), trimethylene-1,3-bis(N,N-dimethyl-N-dodecylammonium bromide) (4) and ethylene-1,2-bis(N,N-dimethyl-N-dodecylammonium bromide) (5) have been obtained and characterized by FTIR and NMR spectroscopy. DFT calculations have also been carried out. The optimized bond lengths, bond angles and torsion angles calculated by Hartree-Fock/3-21G(d,p) approach have been presented. MIC values for A. niger, P. chrysogenum, C. albicans have been determined and the relationship between MIC and spacer length has been discussed.
