A Comparative Study of Thermodynamic Properties of Structurally Related Phenothiazine Drugs in Aqueous Solution

Usman, Muhammad; Cheema, Mohammad Arif; Khan, Abbas; Farooqi, Zahoor H.; Mosquera, Víctor X.; Siddiq, Muhammad

doi:10.4067/s0717-97072013000300010

Cited by 16 publications

(2 citation statements)

References 5 publications

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“…The following equations (Usman and Siddiq, 2013; Usman et al, 2010, 2013) have been used for determining thermodynamic parameters, namely, free energy change ( ∆G m ), enthalpy change ( ∆H m ), and entropy change ( ∆S m ) for micellization process;

∆ G_{m} = ((), 2 - β) italicRT \ln X_{cmc}

∆ H_{m} = - 2.303 ((), 2 - β) {RT}^{2} ([], \frac{\partial \log X_{italiccmc}}{\partial T})

{∆ G}_{m} = {∆ H}_{m} - T ∆ S_{m}

where R is the universal gas constant (8.314 J mol −1 K −1 ), X cmc is the mole fraction of surfactant, and β is the degree of dissociation (

β = \frac{S_{2}}{S_{1}}

, where S 1 and S 2 are slopes of straight lines before and after micellization, respectively).…”

Section: Methodsmentioning

confidence: 99%

Rhamnolipid–Metal Ions (Cr^VI and Pb^II) Complexes: Spectrophotometric, Conductometric, and Surface Tension Measurement Studies

Hari

Upadhyay

2020

J Surfact & Detergents

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The formation of rhamnolipid complexes with metal ions of chromium (VI) and lead (II) has been studied spectrophotometrically, conductometrically, and by surface tension measurement. The values of the critical micelle concentration (CMC) of rhamnolipid, obtained by spectroscopic, conductometric, and surface tension measurements, were 5.2 × 105, 5.0 × 105, and 5.3 × 105 mol.dm−3, respectively, which are in close agreement. An increase in CMC on increasing metal ion content in the rhamnolipid solution and a shift in λmax in the spectra of rhamnolipid indicated the formation of a complex between rhamnolipid and both the metal ions, namely, chromium (VI) and lead (II). The values of stability constants for the {rhamnolipid–chromium (VI)} and {rhamnolipid–lead (II)} complexes have been determined by spectroscopic data and were as 0.58 × 104 and 0.50 × 104 at 308 K, respectively. The thermodynamic parameters for micellization, namely, free energy change (∆Gmic), entropy change (∆Smic), and heat enthalpy change (∆Hmic), have been determined by conductivity measurements. An increase in the negative value of ∆Gmic and a decrease in the value of ∆Smicon increasing metal ion content in the surfactant solution indicated lower micellization of rhamnolipid in the presence of metal ions. The electrostatic attractions and entrapment of chromium (VI) in the micelles of the biosurfactants were found to be responsible for {rhamnolipid–lead (II)} and {rhamnolipid–chromium (VI)} complexes, respectively.

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∆ G_{m} = ((), 2 - β) italicRT \ln X_{cmc}

∆ H_{m} = - 2.303 ((), 2 - β) {RT}^{2} ([], \frac{\partial \log X_{italiccmc}}{\partial T})

{∆ G}_{m} = {∆ H}_{m} - T ∆ S_{m}

where R is the universal gas constant (8.314 J mol −1 K −1 ), X cmc is the mole fraction of surfactant, and β is the degree of dissociation (

β = \frac{S_{2}}{S_{1}}

, where S 1 and S 2 are slopes of straight lines before and after micellization, respectively).…”

Section: Methodsmentioning

confidence: 99%

Rhamnolipid–Metal Ions (Cr^VI and Pb^II) Complexes: Spectrophotometric, Conductometric, and Surface Tension Measurement Studies

Hari

Upadhyay

2020

J Surfact & Detergents

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“…Equation-1 was applied to the pre-micellar region. 27 The value of min Γ and A min are listed in Tables 1-3 and plotted in Figure 5. The results concluded that the longer hydrophobic tail of C 19 TAB is more closely packed at the air-water interface.…”

Section: Conductancementioning

confidence: 99%

Effect of Concentration and Molecular Mass of Peo on the Micellization and Thermodynamic Behaviour of Cetyltrimethylammonium Bromide (Ctab) in Aqueous Peo-Ctab Mixed System

Rauf

Baloch

Khan

et al. 2016

J. Chil. Chem. Soc.

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Polymer-surfactant mixed systems have attracted much attention due to their importance from the academic as well as applied point of view. Therefore, to evaluate the thermodynamic properties of polymer-surfactant self-assembled system, the critical micelle concentration (CMC) of CTAB and CTAB/PEO mixture was determined at different CTAB/PEO ratios and various molecular masses of PEO by employing surface tensiometric, conductometric, and light scattering techniques. The CMC of CTAB was increased as the concentration and molecular mass of the polymer increased. Using surface tensiometry, the thermodynamics of adsorption, surface excess concentration and the minimum area occupied by surfactant molecules for different surfactant-polymer mixtures were also evaluated. CMC, area per molecule, free energy of micellization and degree of counter ion binding were also determined. It was found that most of these parameters increased as the concentration of polymer increased, whereas the surface excess concentration was found to decrease by increasing the polymer ration in the mixed system. The hydrodynamic radius (R h ) of the micelle particles calculated from dynamic light scattering technique showed a similar trend. Most of the results from different techniques support each others.

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Spectrophotometric and conductometric study of the interaction of saponin with chromium(VI) and lead(II)

Upadhyay

Hari

2019

Int. J. Environ. Sci. Technol.

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A Comparative Study of Thermodynamic Properties of Structurally Related Phenothiazine Drugs in Aqueous Solution

Cited by 16 publications

References 5 publications

Rhamnolipid–Metal Ions (Cr^VI and Pb^II) Complexes: Spectrophotometric, Conductometric, and Surface Tension Measurement Studies

Rhamnolipid–Metal Ions (Cr^VI and Pb^II) Complexes: Spectrophotometric, Conductometric, and Surface Tension Measurement Studies

Effect of Concentration and Molecular Mass of Peo on the Micellization and Thermodynamic Behaviour of Cetyltrimethylammonium Bromide (Ctab) in Aqueous Peo-Ctab Mixed System

Spectrophotometric and conductometric study of the interaction of saponin with chromium(VI) and lead(II)

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A Comparative Study of Thermodynamic Properties of Structurally Related Phenothiazine Drugs in Aqueous Solution

Cited by 16 publications

References 5 publications

Rhamnolipid–Metal Ions (CrVI and PbII) Complexes: Spectrophotometric, Conductometric, and Surface Tension Measurement Studies

Rhamnolipid–Metal Ions (CrVI and PbII) Complexes: Spectrophotometric, Conductometric, and Surface Tension Measurement Studies

Effect of Concentration and Molecular Mass of Peo on the Micellization and Thermodynamic Behaviour of Cetyltrimethylammonium Bromide (Ctab) in Aqueous Peo-Ctab Mixed System

Spectrophotometric and conductometric study of the interaction of saponin with chromium(VI) and lead(II)

Contact Info

Product

Resources

About

Rhamnolipid–Metal Ions (Cr^VI and Pb^II) Complexes: Spectrophotometric, Conductometric, and Surface Tension Measurement Studies

Rhamnolipid–Metal Ions (Cr^VI and Pb^II) Complexes: Spectrophotometric, Conductometric, and Surface Tension Measurement Studies