- Synthesis and evaluation of novel cationic gemini surfactants based on Guava crude fat as petroleum-collecting and dispersing agents
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Cationic gemini surfactants based on Guava fat mixed fatty alcohols and isolated fatty alcohols C8, C12, C16, C18 were synthesized. The surface properties and thermodynamic parameters of micellization process, of the new cationic gemini surfactants have been investigated. Furthermore, the petroleum-collecting and dispersing indices of obtained surfactants, in waters of varying salinity have been studied. The results revealed that the tendency of these surfactants toward adsorption process was more than its tendency micellization and show high petroleum-collecting and dispersing properties.
- Abo-Riya, Mohammed,Tantawy, Ahmed H.,El-Dougdoug, Wagdy
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p. 642 - 650
(2016/07/06)
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- Towards room-temperature ionic liquid crystals
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Ionic liquid crystals (ILCs) with displaying birefringence have great potential in various (bio)sensor schemes. So far, their high transition temperatures prevent their application. We demonstrate in a novel series of ILCs, based on archetypical mesogens, how to reduce clearing temperatures and we explain our results qualitatively.
- Fernandez, Alexandra Alvarez,De Haan, Laurens T.,Kouwer, Paul H.J.
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p. 354 - 357
(2013/07/11)
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- Synthesis and surface active properties of gemini cationic surfactants and interaction with anionic azo dye (AR52)
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A homologous series of new gemini cationic surfactants were synthesized and characterized using micro elemental analysis, FTIR, 1H-NMR and mass spectra. The surface activities of these amphiphiles were determined based on the data of surface tension. Critical micelle concentration, effectiveness of the surface tension reduction, efficiency of adsorption, maximum surface excess, minimum surface area and critical packing parameter were evaluated. The effect of cationic micelles on solubilization of anionic azo dye, sulforhodamine B (Acid Red 52) in aqueous micellar solution of the synthesized gemini cationic surfactants was studied at pH 6.9 ± 0.5 and 25°C. The results showed that the solubility of dye rose with increasing surfactant concentration as a consequence of some association between the dye and the micelles. It was also observed that the aggregation of surfactant and dye takes place at a surfactant concentration below the CMC of the individual surfactant. The partition coefficients between the bulk water and surfactant micelles as well as the Gibbs energies of distribution of dye between the bulk water and surfactant micelles were calculated using a pseudo-phase model. The effect of the hydrophobic chain length of Gemini cationic surfactants on the distribution parameters was also reported. The results show favorable solubilization of dye in cationic micelles. AOCS 2011.
- Abdel-Salam, Fatma H.,El-Said, Asrar G.
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experimental part
p. 371 - 379
(2012/07/14)
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- Soft antimicrobial agents: Synthesis and activity of labile environmentally friendly long chain quaternary ammonium compounds
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A series of soft quaternary ammonium antimicrobial agents, which are analogues to currently used quaternary ammonium preservatives such as cetyl pyridinium chloride and benzalkonium chloride, were synthesized. These soft analogues consist of long alkyl chain connected to a polar headgroup via chemically labile spacer group. They are characterized by facile nonenzymatic and enzymatic degradation to form their original nontoxic building blocks. However, their chemical stability has to be adequate in order for them to have antimicrobial effects. Stability studies and antibacterial and antiviral activity measurements revealed relationship between activity, lipophilicity, and stability. Their minimum inhibitory concentration (MIC) was as low as 1 μg/mL, and their viral reduction was in some cases greater than 6.7 log. The structure-activity studies demonstrate that the bioactive compounds (i.e., MIC for Gram-positive bacteria of 10μg/mL) have an alkyl chain length between 12 and 18 carbon atoms, with a polar headgroup preferably of a small quaternary ammonium group, and their acquired inactivation half-life must be greater than 3 h at 60 °C.
- Thorsteinsson, Thorsteinn,Másson, Már,Kristinsson, Karl G.,Hjálmarsdóttir, Martha A.,Hilmarsson, Hilmar,Loftsson, Thorsteinn
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p. 4173 - 4181
(2007/10/03)
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