scholarly journals Thermodynamics of micellization of hexadecyltrimethylammonium bromide in propylene glycol-water mixture: A conductivity study

2014 ◽  
Vol 12 (1) ◽  
pp. 17-26
Author(s):  
Aleksandra Janosevic-Lezaic ◽  
Nikola Paunovic ◽  
Natasa Pejic
Keyword(s):  
Propylene Glycol ◽  
Cetyltrimethylammonium Bromide ◽  
Compensation Effect ◽  
Micelle Formation ◽  
Critical Micellar Concentration ◽  
Hexadecyltrimethylammonium Bromide ◽  
Water Mixture ◽  
Ionization Degree ◽  
Molar Gibbs Free Energy ◽  
Micellization Process

Micellization of hexadecyltrimethylammonium bromide (syn. cetyltrimethylammonium bromide, CTAB) in propylene glycol-water (30% v/v) binary mixture, as well as the thermodynamic properties of the resulting micelles, were investigated by electrical conductivity measurements. The conductivity data were used to determine both the critical micellar concentration (CMC) and the micellar ionization degree (?) of CTin the temperature range 298.2-310.2 K. The equilibrium model of micelle formation was applied in order to obtain the thermodynamic parameters (the standard molar Gibbs free energy, ?Gm0, enthalpy, ?Hm0 and entropy, ?Sm0) of the micellization process. The values of DGm0 and DHm0 were found to be negative at all investigated temperatures, while the values of ?Sm0 were positive and became more positive as temperature increased. A linear dependence between ?Sm0 and ?Hm0, i.e. an enthalpy-entropy compensation effect, was observed.

Effect of cetyltrimethylammonium bromide on the electrochemiluminiscence and electrooxidation of luminol

1983 ◽  
Vol 48 (2) ◽  
pp. 477-483 ◽  
Author(s):  
Jan Lasovský ◽  
František Grambal
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Linear Sweep Voltammetry ◽  
Critical Micellar Concentration ◽  
Peak Height ◽  
Anodic Peak ◽  
Alkaline Solutions ◽  
Platinum Electrodes ◽  
Micellar Solutions ◽  
Linear Sweep ◽  
Low Concentrations

The electrooxidation of luminol in alkaline solutions in the presence of cetyltrimethylammonium bromide (I) was studied by linear sweep voltammetry on fixed and vibrating platinum electrodes. The presence of I in low concentrations (below the critical micellar concentration) brings about aggregation of the luminol, which is manifested by an increase in the anodic peak height and its shift towards lower potentials. In micellar solutions the peak height decreases owing to the slower diffusion of the bulkier micelles, the shift to lower potentials being preserved. The light-voltage curves correspond with the voltammetric curves, exhibiting identical shifts of the peak potentials in dependence on the concentration of the surfactant.

scholarly journals Shear flow behavior and dynamic viscosity of few-layer graphene nanofluids based on propylene glycol-water mixture

2020 ◽  
Vol 316 ◽  
pp. 113875 ◽  
Author(s):  
Samah Hamze ◽  
David Cabaleiro ◽  
Thierry Maré ◽  
Brigitte Vigolo ◽  
Patrice Estellé
Keyword(s):  
Shear Flow ◽  
Propylene Glycol ◽  
Dynamic Viscosity ◽  
Flow Behavior ◽  
Water Mixture ◽  
Layer Graphene ◽  
Few Layer Graphene

scholarly journals Suitability of base liquid in a nanofluid-laden solar flat-plate collector with emphasize on bioglycol

2018 ◽  
Vol 225 ◽  
pp. 04014
Author(s):  
Seyed Reza Shamshirgaran ◽  
Hussain H. Al-Kayiem ◽  
Morteza K. Assadi ◽  
K.V. Sharma
Keyword(s):  
Ethylene Glycol ◽  
Flat Plate ◽  
Propylene Glycol ◽  
Energetic Efficiency ◽  
Water Mixture ◽  
Safe Product ◽  
The Stability ◽  
Flat Plate Collector ◽  
Matlab Programming ◽  
Base Liquid

Ethylene glycol and propylene glycol are commonly used as thermal liquids in solar flat-plate collectors (FPCs). They are utilized as base liquid as well as for improving the stability of nanofluids in FPCs. The objective of the present paper is to introduce a renewable-derived bio glycol for use as base liquid in FPCs. The effect of base ratio (BR) of different glycol products on the performance of a conventional FPC and a nanofluidladen FPC is investigated in this paper to determine its suitability. MATLAB programming was employed for modeling the performance of the FPC operating with copper and cerium oxide nanomaterials. The results show that 20:80 bio glycol/water mixture is capable of enhancing the FPC’s energetic efficiency up to 72.1% which is higher than with either ethylene glycol and propylene glycol. The energy efficiency of a glycol-based nanofluid-filled FPC decreases with the base ratio of all three glycol products. Since bio glycol is a non-toxic and safe product, it can be utilized as a safe and environmentally-friend antifreeze and base liquid in nanofluid-filled FPCs.

scholarly journals Litogenolitic and solubility properties of products obtained from common ivy extract (Hederae helicis e folium) and medium of diversified polarity (εM)

2019 ◽  
Vol 65 (1) ◽  
pp. 20-31 ◽  
Author(s):  
Elżbieta Nowak ◽  
Zbigniew Marczyński ◽  
Beata Skibska ◽  
Michał Jakub Nachajski ◽  
Jerzy Jambor ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Thermodynamic Potential ◽  
Micelle Formation ◽  
Critical Micellar Concentration ◽  
Herbal Drugs ◽  
Efficacy And Safety ◽  
Micellar Solubilization ◽  
Hedera Helix ◽  
Inflammatory Drugs ◽  
Preformulation Studies

Summary Introduction: Common ivy (Hedera helix) is a plant used successfully in the treatment of various ailments. This is possible owing to the unique set of substances contained in it such as large amount of saponins, flavonoids, phenolic acids and phytosterols as well as polyacetylenes and coumarins. All these substances have been used in the production of cosmetic and medicinal preparations. Clinical trials on the efficacy and safety of dry ivy leaf extract have shown its high efficacy, comparable to synthetic medications, and better tolerance of herbal drugs. Objective: Investigations were performed on model ivy leaf (Hedera helix) extracts which were created using a medium of diversified polarity ( εM). Measurements of viscosity and surface activity on phase boundary were performed. During preformulation studies attention was drawn to the possibility of micellar solubilization of cholesterol and selected structures of nonsteroidal anti-inflammatory drugs (NSAIDs) – ketoprofen. Methods: Viscosity measurements of Extractum Hederae helicis e folium aqueous solutions and in 0.1 mol HCl were performed according to the Polish Standard with Ubbelohde dilution viscometer. The surface tension of aqueous solutions $- \Delta \gamma _{{\rm{sol}}}^{25}$ of Hederae helicis e folium extracts was determined according to the Polish Standard with stalagmometric method. Critical micellar concentration (cmc) was calculated. This enabled to evaluate the dependence $\Delta {\rm{G}}_{\rm{m}}^0 = 2.303$ RT×log cmc of the thermodynamic potential of micelle formation ( $\Delta {\rm{G}}_{\rm{m}}^0$ ). Results: It has been confirmed in the conducted comparative studies that aqueous solutions of Extr. Hederae helicis e folium created with maltodextrin as well as with SiO2 – maltodextrin result in micellar solubilization. The increase of granulometric size of cholesterol particle to Ø 1.60 mm decreased the amount of solubilized cholesterol but solubility preferences of the extracts were maintained. Conclusions: Model extracts produced from Hederae helicis e folium with diversified polarity of the extraction medium (water – ethanol) are characterized by appropriate solubility of the components which results not only from the presence of chlorophyll and its derivatives in the extract but also from the technique used for spray drying of the extract.

scholarly journals A Study of Local Anaesthetics. Part 202. Determination of the Critical Micellar Concentration of Carbisocainium Chloride in Water Using Spectral Methods and the Probe Pyrene

2013 ◽  
Vol 60 (1) ◽  
pp. 1-6 ◽  
Author(s):  
J. Gališinová ◽  
F. Andriamainty ◽  
I. Malík ◽  
J. Čižmárik ◽  
J. Karlovská ◽  
...  
Keyword(s):  
Spectral Methods ◽  
Emission Spectroscopy ◽  
Surfactant Concentration ◽  
Fluorescence Emission ◽  
Local Anaesthetics ◽  
Critical Micellar Concentration ◽  
Ratio Data ◽  
Micellization Process ◽  
Second Procedure

The micellization process of the local anaesthetic carbisocainium chloride in water was investigated by two spectral methods using the probe pyrene. First, the absorption spectroscopy in UV/VIS region was based on studying changes in characteristic absorption spectrum of pyrene in presence of surfactant. The resultant plot of the sum of absorbances for all the major pyrene peaks as a function of the total surfactant concentration shows, around the critical micellar concentration, a typical sigmoidal increase. The fluorescence emission spectroscopy in UV/VIS region of spectrum by the probe pyrene, second procedure, was applied for determination of the cmc from the measurements of the pyrene I1 /I3 ratio as a function of the surfactant concentration. The pyrene ratio data were fitted by the Boltzmann-type sigmoid of decreasing character.

Quaternary Heteroarenium Aldoximes as Catalysts for Cleavage of Phosphate Esters

1995 ◽  
Vol 60 (5) ◽  
pp. 883-893 ◽  
Author(s):  
František Hampl ◽  
Jiří Mazáč ◽  
František Liška ◽  
Jiří Šrogl ◽  
Lubomír Kábrt ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Critical Micellar Concentration ◽  
Considerable Effect ◽  
Phosphate Esters ◽  
Hexadecyltrimethylammonium Bromide ◽  
Hydrolytic Cleavage ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Diphenyl Phosphate ◽  
Hydrolysis Of

1-Methyl- (Ia - Id) and 1-dodecyl-2-, 3- and 4-hydroxyiminomethylpyridinium salts (Ie - Ih), as well as 1-methyl- (IIa) and 1-dodecyl-3-hydroxyiminomethylpyridazinium salts (IIb, IIc), were synthesized as catalysts for hydrolytic cleavage of organophosphates. The activities of the prepared catalysts were evaluated by measuring rate constants of hydrolysis of 4-nitrophenyl diphenyl phosphate (PNPDPP) under conditions of a pseudo-first-order reaction. The observed reactivity of pyridinium aldoximes Ia - Ih towards PNPDPP in neutral or slightly basic aqueous solutions (pH 7.2 and 7.8) depends on the acidity of the hydroxyimino group. The cleavage of PNPDPP is strongly accelerated in solutions of 1-dodecylhydroxyiminomethylpyridinium salts Ie - Ih above their critical micellar concentration (CMC). Considerable effect on the velocity of PNPDPP cleavage was observed when quaternary pyridinium aldoximes Ie - Ih were comicellized with inert cationic tenside hexadecyltrimethylammonium bromide (CTAB). 1-Dodecyl-3-hydroxyiminomethylpyridazinium salts IIb and IIc were unstable in aqueous solutions under the above-mentioned conditions.

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