Thermodynamics of Micellization of Nonionic Saccharide-Based N-Acyl-N-alkylaldosylamine and N-Acyl-N-alkylamino-1-deoxyalditol Surfactants

Abstract

). Thermodynamics of micellization of nonionic saccharide-based N-acyl-N-alkylaldosylamine and Nacyl-N-alkylamino-1-deoxyalditol surfactants. Langmuir, 15(6), 2009Langmuir, 15(6), -2014 https://doi.org/10.1021/la981404w Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Eight homologous series of nonionic carbohydrate-derived surfactants in which the alkyl chains are linked through N-acylated amine bonds were synthesized, and their critical micelle concentrations (cmc's) and standard enthalpies of micellization were determined using titration microcalorimetry. Gibbs energies of micellization (∆micG°) were calculated from the critical micelle concentrations. N-Acyl-N-alkylaldosylamines (acyl ) acetyl/propionyl, aldosyl ) glucosyl/lactosyl) and N-acyl-N-alkylamino-1-deoxyalditols (acyl ) acetyl/propionyl, alditol ) glucitol/lactitol) with alkyl chain lengths of 8, 10, and 12 carbon atoms show a 10-fold decrease in cmc when the length of the chain is increased by two methylene groups. The enthalpograms for the C8 analogs are more complicated than those for the C10 and C12 analogs. Therefore, the enthalpograms were modeled using a computer-based program which takes account of the nonideal properties of the solutions, yielding enthalpies of micelle formation. Increments in the thermodynamic parameters show satisfactory self-consistency. Each CH2 group contributes -2.4 kJ mol -1 to ∆micH°, ∆micG°-(CH2) is -3.0 kJ mol -1 for each series, and T∆micS°(CH2) is 0.7 kJ mol -1 at 40°C. Although the change in entropy is the main driving force for micellization, the enthalpy of micellization may also contribute significantly to the Gibbs energy of micellization, particularly for longer alkyl chains.

Synthesis and evaluation of N-alkyl-β-d-glucosylamines on the growth of two wood fungi, Coriolus versicolor and Poria placenta

“…[16][17][18][19][20][21][22] In the past, GPA, OcGPA and DoGPA were partially characterized by NMR spectroscopy. In this study, we fully characterized all synthesized glucosylamines using both FTIR and NMR spectroscopy.…”

“…The methods previously reported 16,18,19,22 were slightly modified and used to synthesize DHEtGPA, BuGPA, HeGPA, OcGPA and DoGPA. Reactions carried out between D-glucose and different alkylamines such as diethanolamine, butylamine, hexylamine, octylamine and dodecylamine in MeOH or EtOH gave DHEtGPA, BuGPA, HeGPA, OcGPA and DoGPA, respectively.…”

Understanding organic reactions in water: from hydrophobic encounters to surfactant aggregates

“…62 Titration calorimetric data for nonionic carbohydrate-derived surfactants 63 show interesting but complicated patterns in the contributions to standard Gibbs energies and enthalpies of micelle formation. A similar comment applies to aqueous solutions containing alkylpolyoxyethylene glycol ethers.…”

Heat Evolution of Micelle Formation, Dependence of Enthalpy, and Heat Capacity on the Surfactant Chain Length and Head Group

“…In other words, dissociation of micelles (demicellization) is characterized by a positive and high heat capacity, C P , and is exothermic at low temperatures but endothermic at high temperatures (8). Hence, at a specific temperature, T * , demicellization is athermal (13).…”

“…Recently, it has been hypothesized that head group-head group interactions make temperature-independent exothermic contribution to the heat of dissociation of micelles (13 heat capacity associated with demicellization C P,chain heat capacity associated with transfer of polar head from micelles to water C P,head heat capacity associated with demicellization of head groups…”