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An Insight into Green Microwave-Assisted Techniques
Published in Banik Bimal Krishna, Bandyopadhyay Debasish, Advances in Microwave Chemistry, 2018
Natalia A. Gomez, Maite V. Aguinaga, Natalia Llamas, Mariano Garrido, Carolina Acebal, Claudia Domini
A similar approach was proposed by Hu et al. to extract triazines from honey samples [175]. Here, 1-Dodecanol was selected as an extracting solvent due to its low density and solubility in water and a melting point near room temperature. The extraction was performed using 2.0 g of honey dissolved in 10.0 mL of water, previously filtered. Since the extraction efficiency increased when the analytes where in their neutral form, the pH value of the sample was studied between 2.0 and 8.0, and 5.0 was selected as optimum. The addition of salt increased the viscosity of the sample solution, and the extraction efficiency decreased. Thus, the addition of salt was not recommended. 70 µL of 1-Dodecanol was added to the sample, and the mixture was irradiated at 300 W for 40 s to achieve the dispersion of the solvent by increasing its solubility and hence, accelerating the extraction. Then, the sample was centrifuged to separate the extractant from the solution. The tube was cooled in an ice bath for 5 min and the solvent drop was solidified, so it can be easily collected. The drop was transferred to a vial, diluted with methanol and analyzed by HPLC.
Developing of thermoregulating cotton fabric by incorporating of the poly(methyl methacrylate-co-methacrylamide)/fatty alcohol latent heat storing nanocapsules
Published in The Journal of The Textile Institute, 2022
Simge Özkayalar, Sennur Alay-Aksoy
In two-stage procedure, a 12.5 g quantity of core material (n-dodecanol or n-tetradecanol) was emulsified in 80 mL of distilled water at 50 °C by adding a 1 g of Triton 100 surfactant and stirring in speed of 2000 rpm. A 6.25 g MMA, a 0.5 mL of ferrous sulfate heptahydrate solution, a 0.125 g of ammonium persulfate, a 1.25 g of ethylene glycol dimethacrylate were added to the emulsion and stirring speed was decreased to 1000 rpm. A 0.125 g of sodium thiosulfate, 0.5 g of tert-Butyl hydroperoxide was added to emulsion at 75 °C and then reaction medium was heated to 85 °C. Reaction was conducted for 2 h at stirring speed of 1000 rpm to complete first step of process. To start second-stage of the process, a 0.5 g of Triton X100, a 6.25 g of MMA, a 1.25 g of MAA, a 0.25 mL of ferrous sulfate heptahydrate solution, a 0.0625 g of ammonium persulfate, and a 0.625 g of ethylene glycol dimethacrylate were added to reaction medium. Finally, a 0.0625 g of sodium thiosulfate and 0.25 g of tert-Butyl hydroperoxide were added and the reaction was carried out at 85 °C for 2 h. The abbreviated names and contents of the nanocapsules were tabulated in Table 1.
Phase behavior and microstructure of sugar surfactant-ionic liquid microemulsions
Published in Journal of Dispersion Science and Technology, 2021
Shehnaz H. Solanki, Sandeep R. Patil
The phase behavior and microstructure of a ternary system water/1-butyl-3-methylimidazolium hexafluorophosphate/Sugar Surfactant was studied as a function of temperature and sugar surfactant mass fraction, γ. In the present study, a hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was used to replace commonly used organic solvents (n-alkanes) as an oil/non-polar phase substitute in ternary microemulsion formulations, wherein, a sugar based alkyl polyglycoside nonionic surfactant was used instead of a conventional nonionic surfactant (i.e., alkyl polyoxyethylene ether class) to solubilize hydrophobic ionic liquid and water. The effect of alkanols of variable chain length (octanol, decanol and dodecanol) as co-surfactant on the phase behavior and microstructure of ionic liquid/sugar surfactant/water ternary microemulsion systems was also investigated. Moreover, phase behavior and microstructure of ternary systems, 1-butyl-3-methylimidazolium tetrafluoroborate:water (1:1)/sugar surfactant/n-alkanes (alkanes of varying chain length, i.e., octane, decane and dodecane) was also studied. The intent of the present work is to achieve the reduction in surfactant concentration required to solubilize the two immiscible solvents (Ionic Liquid and water) by replacing the alkyl polyglycolether (CiEj) surfactants by a “green alternative”, viz. alkyl glycoside or sugar surfactants (CnGm) in a ternary system and formulating microemulsion systems that are stable over a wide temperature range.
Effect of the surfactant alkyl chain length on the stabilisation of lyotropic nematic phases
Published in Liquid Crystals, 2018
Erol Akpinar, Cihan Canioz, Meric Turkmen, Dennys Reis, Antônio Martins Figueiredo Neto
In recent studies [8,13–16], we have provided new results to understand the role of some constituents of lyotropic mixture to stabilise the different nematic phases, especially the biaxial one. For instance, the kosmotrope–chaotrope interactions between the head groups of the surfactants and ions of electrolytes added to the mixture have significant effect on the stabilisation of the NB phase [12]. To obtain a lyotropic mixture exhibiting the NB phase, there should be a molecular segregation between the surfactant and the co-surfactant in the micelles [15,17,18]. All the mixtures reported in the literature showing the three nematic phases have, besides the main surfactant, long chain alcohols, such as decanol [5,19–22], undecanol [8,15], dodecanol [14], hexadecanol [23] and DaCl (decylammonium chloride) [18] as co-surfactants. In a previous work we showed that it is possible to obtain the biaxial nematic phase in a lyotropic mixture taking into account the relationship between the alkyl chain length of alcohol (Calc) and main surfactant (CSurf) molecules. The main surfactant alkyl chain length should be Calc = CSurf ± 2 [15].