Modulating the Aggregation Behavior of 1-Methyl-3-Octylimidazolium Chloride by Alcohols in Aqueous Media

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• 作者：Amalendu Pal ; Alka Yadav
• 刊名：Journal of Surfactants and Detergents
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：19
• 期：5
• 页码：1053-1062
• 全文大小：629 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Industrial Chemistry and Chemical Engineering
  Surfaces and Interfaces and Thin Films
  Polymer Sciences
  Waste Water Technology, Water Pollution Control, Water Management and Aquatic Pollution
  Analytical Chemistry
  Physical Chemistry
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1558-9293
• 卷排序：19

文摘

The self-organization and aggregation behavior of a surface active ionic liquid (SAIL) 1-methyl-3-octylimidazolium chloride [C₈mim]Cl, was investigated in aqueous solutions of alcohols 1,2-propanediol and 1-propanol in different compositions using conductivity, surface tension and fluorescence measurements at room temperature. This surface active ionic liquid was synthesized by the reaction of 1-methylimidazole with 1-chlorooctane. Fluorescence spectroscopy was employed to get detailed insight into the local microenvironment of the aggregates, critical aggregation concentrations (CAC) and aggregation number (N_agg.). Degree of ionization (α), CAC and various thermodynamic parameters like the standard Gibbs free energy of aggregation (ΔG_agg.0), standard enthalpy of aggregation (ΔH_agg.0) and standard entropy of aggregation (ΔS_agg.0) were calculated using conductivity measurements at different temperatures (288.15, 298.15 and 308.15 K). The surface activity of the IL in various mixed solvents was evaluated from surface tension measurements by calculating various surface parameters like the minimum surface area occupied by a single ionic liquid molecule (A_min), adsorption efficiency (pC₂₀), maximum excess concentration at the surface (Γ_max), effectiveness of surface tension reduction(Π_CAC), surface tension at CAC (γ_CAC), p (packing parameter) and CAC at different compositions. Increases in the CAC values were observed with the increase in the amount of alcohols which is attributed to the balancing between electrostatic and hydrophobic interactions. The results from different techniques show that the CAC increases with increase in the amount of the alcohol which is due to the solubilization of the IL molecules which delays the aggregation process. This shows that the spontaneity of the aggregation process of IL decreases with the increase in the concentration of alcohols in water.KeywordsIonic liquidAlcoholsConductanceSurface tensionFluorescence