The Asian Journal of Experimental Chemistry

Anil Kumar ¹, Deepti Tyagi ¹, Simmi Tyagi ², Deepika Shukla ¹

Affiliations
1 Department of Chemistry, D.A.V. (P.G.) College, Muzaffarnagar (U.P.), IN
2 Central Building Research Institute, CBRI (A Constitutent Establishment of CSIR), Ministry of Science and Technology (Government of India), Roorkee (Uttarakhand), IN

Abstract

The specific conductance, k (mS cm^-1) of alkaline earth metal (Mg/Ca/Sr/Ba) laurates in mixed solvent (50% methanol +50% chloroform) has been measured (30-50^oC) in order to look into the dissociation / association behaviour of these surfactant systems. The data for critical micelle concentration (c.m.c) help characterising their micellar behaviour. The significant parameters viz. degree of dissociation (α), dissociation constant(K_D) and limiting equivalent conductance at infinite dilution (μ_o) have been deduced for pre-micellar region (dilute range).Thermodynamic parameters viz., enthalpy, free energy and entropy changes for both dissociation and association processes have also been computed.

Keywords

Metal Laurates, Conductance, Dissociation, Association, Critical Micelle Concentration (C.M.C), Thermodynamic Parameters.

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Anil Kumar ¹, Deepti Tyagi ¹, Simmi Tyagi ², Deepika Shukla ¹

Affiliations
1 Department of Chemistry, D.A.V. (P.G.) College, Muzaffarnagar (U.P.), IN
2 Central Building Research Institute, CBRI (A Constitutent Establishment of CSIR), Ministry of Science and Technology (Government of India), Roorkee (Uttarakhand), IN

Abstract

The density measurement, ρ (gcm^-3) for alkaline earth metal (Mg/Ca/Sr/Ba) laurates in non-aqueous medium (50% methanol +50% chloroform) at different temperatures (30-50^oC) has been used to evaluate various significant parameters viz. apparent molar volume (Φ_v) and expansibility (E⁰_surf) to explore their solution behaviour. The critical micclle concentration (c.m.c.) as ascertained from ρ-C plots, is found to decrease with increasing temperature and vary with different metals as Mg>Ca>Sr>Ba. Density for these solutions increases with increasing surfactant concentration and decreasing temperature. Partial molar volume (Φ^o_v) and experimental limiting slope (Sv) as obtained from Masson's equation provide information on solute-solvent and solute-solute interactions, respectively. Apparent molar volume (Φ_v) is found to increase with increasing concentration and increasing temperature.

Keywords

Alkaline Earth Metal Laurates, Critical Micelle Concentration (c.m.c), Density (ρ), Apparent Molar Volume (Φ_v), Partial Molar Volume (Φ^o_v), Expansibility.

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Anil Kumar ¹, Deepika Shukla ¹, Deepti Tyagi ¹

Affiliations
1 Department of Chemistry, D.A.V. (P.G.) College, Muzaffarnagar (U.P.), IN

Abstract

The present investigation deals with density measurement of alkali (Li, Na, K) and alkaline earth metal (Mg, Ca, Sr, Ba) myristates in 50% methanol-50% chloroform (V/V) solvent-mixture at 30°-50°C. The data have been used to determine critical micelle concentration, cmc, and compute other significant parameters viz. apparent (Φ_v) and partial (φ°_v) molar volumes and partial molar expansibility, E°surfactant. The decreasing cmc with the increase in temperature is in agreement with the result obtained from specific conductance measurements. The variation of cmc with alkali and alkaline earth metals also follows the same order as was found in the study on conductance measurements.

Keywords

Critical Micelle Concentration (c.m.c.), Density, Molar Volume and Expansibility.

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Anil Kumar ¹, Deepika Shukla ¹, Deepti Tyagi ¹

Affiliations
1 Department of Chemistry, D.A.V. (P.G.) College, Muzaffarnagar (U.P.), IN

Abstract

The present investigation deals with the relative facets of alkali (Li, Na, K) and alkaline earth metal (Mg, Ca, Sr, Br) Myristates at different temperatures (30°-50°C). Thermodynamic parameters (change in enthalpy/free energy/entropy) for both dissociation and association processes have been used to look into the solution behaviour of these surfactants in 50% methanol +50% chloroform (V/V). Besides thermodynamic consideration, other parameters such as degree of dissociation, a and dissociation constant, K_D etc are used to delve into the dissociation aspects of these systems. The data for critical micelle concentration, cmc are also reported and explained.

Keywords

Specific Conductivity, Alkali and Alkaline Earth Metal Myristates, Dissociation/Association Behaviour, Thermodynamic Approach, Critical Micelle Concentration (CMC).

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