Modeling Chemical Reactivity in Ionic Detergent Micelles: a Review of Fundamentals

Quina, Frank H.

doi:10.5935/0103-5053.20150311

Cited by 2 publications

(4 citation statements)

References 1 publication

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“…The α mic value obtained was 0.412 ± 0.005, indicating that nearly 40% of chloride ions are free in the bulk, in which the mobility in the solution due to the interaction with the micelle is not changed. 24,25 The cmc and α mic values reported here are consistent with those obtained by Gonzaleź-Peŕez et al 26 (cmc = 0.97055 mmol kg −1 and α mic = 0.417, at 298.15 K).…”

Section: Interaction Between Pvoh (Or Pvcooh) and C 16supporting

confidence: 91%

Thermodynamics of Aggregation between the Cationic Surfactant and Polymer Based on Biodegradable Poly(vinyl Alcohol)

et al. 2022

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The formation of aggregates between carboxylated (PVCOOH) or neutral hydrolyzed (PVOH) poly(vinyl alcohol) and hexadecylpyridinium chloride (C16PyCl) was examined by conductimetry, turbidimetry, and isothermal titration calorimetry (ITC) in the presence of different NaCl concentrations. The interaction between the polymers and C16PyCl in pure water showed a critical aggregation concentration (cac = 0.8 mmol L–1) only for the neutral polymer. PVCOOH interacted with the surfactant through electrostatic attraction, forming macroscopic aggregates. Integral enthalpy changes for aggregate formation (ΔH agg) obtained from ITC curves varied from −0.61 (for the PVOH system in pure water) to −4.14 kJ mol–1 (for PVOH in the presence of 10.0 mmol L–1 NaCl), indicating that the formation of the aggregates was enthalpically favored. However, hydrophobic interactions drove the process for low surfactant concentration for both polymers. Saturation concentrations (C2) obtained from conductimetry were smaller than those from ITC, revealing that the binding of C16PyCl on the chain of the polymers at higher surfactant concentrations shows the same electric properties as that of free micelles on the solution. Increase of the ionic strength favored the aggregation and decreased the complexity of the ITC curves, suggesting that the reorganization of the surfactant monomers on the polymeric chain with the increase in their concentration was suppressed.

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Section: Interaction Between Pvoh (Or Pvcooh) and C 16supporting

confidence: 91%

Thermodynamics of Aggregation between the Cationic Surfactant and Polymer Based on Biodegradable Poly(vinyl Alcohol)

et al. 2022

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“…The cation structures differ as well, making direct comparisons difficult. Also, Marino and Kreuer mentioned that a trend found in their workbase stability of a series of n -alkyltrimethylammonium cations RNMe 3 + in 6 M NaOH at 160 °C decreases for R = n -hexyl to R = n -hexadecylmay be rationalized by development of phase-separated micellar aggregates as the alkyl group size is increased, leading to accelerated rates of base decomposition , by the organic medium effect. Thus, the relative base stability of BTMA vs alkyltrimethylammonium in these experiments depends on the alkyl group length.…”

Section: Discussionmentioning

confidence: 76%

“…Chemical reactions in aqueous media containing dispersed organic phases such as associative colloids are a well-studied phenomenon. There is an extensive literature on reactions in micelles, microemulsions, , vesicles, , and emulsions . There are many examples of base-driven hydrolytic reactions which can be accelerated or decelerated in the dispersed phase relative to bulk solution, with details depending on the exact nature of the reaction, reactants, and amphiphile anchoring the colloidal structure.…”

Section: Discussionmentioning

confidence: 99%

“…There is ample precedent for the general mechanism of the particle-driven rate acceleration discussed herein. However, there are some distinguishing features between the system of this work and the organized assemblies studied in the cited literature. − For instance, the salts of this study bear no medium- or long-chain alkyl segments generally enabling micellization and other associative colloidal processes. Also, the DLS data suggest that the particles observed here are much larger than the sub-100 nm particles typically characterizing micellar solutions and microemulsions, yet smaller than the oil droplets in oil-in-water emulsion systems.…”

Section: Discussionmentioning

confidence: 99%

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Characterizing Cation Chemistry for Anion Exchange Membranes—para-Alkyl-Substituted Benzyltetramethylimidazolium and Benzyltrimethylammonium Salts in Base

Pellerite

Lomeda

2021

J. Org. Chem.

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Base stability and degradation of imidazolium-functional materials have been a focus of research on anion exchange membranes for electrochemical devices. Despite extensive work, mechanistic questions can cloud efforts to correlate results from model compounds and polymeric membranes. Here, we report an NMR study of behavior in aqueous KOH of benzyltetramethylimidazolium and benzyltrimethylammonium salts with and without para-alkyl-substitution to probe whether base attack at the alkyl substituent plays a role in the reaction pathways. In all cases, the major products from the imidazolium salts are consistent with hydrolytic ring fragmentation as the principal mode of decomposition. Also, relative decomposition kinetics for both types of salts provided no conclusive evidence for a change in reaction mechanism upon introduction of the alkyl substituent. While our data do not rule out base attack at the alkyl group in the cases where rate differences were noted, these differences appear to be better attributed to reaction medium effects of submicrometer oil phase droplets arising from salt aggregation.

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Modeling Chemical Reactivity in Ionic Detergent Micelles: a Review of Fundamentals

Cited by 2 publications

References 1 publication

Thermodynamics of Aggregation between the Cationic Surfactant and Polymer Based on Biodegradable Poly(vinyl Alcohol)

Thermodynamics of Aggregation between the Cationic Surfactant and Polymer Based on Biodegradable Poly(vinyl Alcohol)

Characterizing Cation Chemistry for Anion Exchange Membranes—para-Alkyl-Substituted Benzyltetramethylimidazolium and Benzyltrimethylammonium Salts in Base

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