Conductometric Studies Research Articles

Viscometric and Conductometric Studies of Solvation Behaviour of Tetraalkylammonium Salts in the Binary Mixtures of Dimethylsulfoxide and Methanol at 298.15 K

Abstract Molar conductance and viscosity of some tetraalkylammonium perchlorates (R4NClO4 where R = Methyl, Ethyl, Propyl, Butyl) have been measured in the concentration range (30–500) × 10−4 mol kg−1 at 298.15 K in the binary mixtures of dimethylsulfoxide (DMSO) + methanol (MeOH) containing 0, 20, 40, 50, 60, 80 and 100 mol% methanol. Conductance data has been analyzed using the Shedlovsky equation and the viscosity data by Jones-Dole equation. The limiting ionic conductances ( λ ± o $\lambda_{\pm}^{o}$ ) were used to calculate the solvated radii (ri ) of the ions. The A and B coefficients of the Jones-Dole equation are positive in all salts. The A coefficients are in reasonable good agreement with the limiting theoretical values (Aη ) calculated using Falkenhagen-Vernon equation. The variation of the ionic B± coefficients as well as the actual solvated radii (ri ) with solvent composition in DMSO + MeOH mixtures show the preferential solvation of tetraalkylammonium ions by MeOH and MeOH-rich region of the mixtures. The tetraalkylammonium ions exhibit solvation in the order Me4N+ > Et4N+ > Pr4N+ > Bu4N+.

Effect of Morphological Structure, Temperature and Solvent on the Association Behavior of Some Copper Salts- Conductometric Study

Effect of Morphological Structure, Temperature and Solvent on the Association Behavior of Some Copper Salts- Conductometric Study

Effect of water hardness on the interaction of cationic dye with anionic surfactants

ABSTRACTThe effect of water hardness causing ions on the critical micelle concentration (cmc) of surfactants was studied using conductivity measurement. Spectrophotometric and conductometric studies of dye and surfactant interaction under the influence of water hardness causing ions were also investigated. It was found that with increasing hardness in water, cmc of the surfactants tends to decrease. The change in the colour of the solution was observed as the degree of hardness increases. Hardness of water can consider as a major contributor of fading or change in colour during washing and cleaning of dyed material. Dye in a surfactant solution containing varying amount of hardness causing ions undergoes a blue shift in the visible region and red shift in ultraviolet region. The comparison between sodium dodecylsulphate (SDS) and saponin natural surfactant showed that turbidity was observed only in the aqueous solution of SDS in the presence of very hard water.

Aggregation Behavior of Sodium Dodecyl Sulfate and Cetyltrimethylammonium Bromide Mixtures in Aqueous/Chitosan Solution at Various Temperatures: An Experimental and Theoretical Approach

AbstractA conductometric study of the mixed micellization behavior between cetyltrimethylammonium bromide (CTAB, a cationic surfactant) and sodium dodecyl sulfate (SDS, an anionic surfactant) was carried out in the absence/presence of various percentages of chitosan in the temperature range of 298.15–318.15 K. The deviations of critical micelle concentration (cmc) from the ideal values indicate the interaction between CTAB and SDS. The micellar mole fraction values according to different proposed models X1Rub (Rubingh), X1M (Motomura), X1Rod (Rodenas), and X1id (ideal mole fraction) were estimated and the results obtained reveal the high contribution of CTAB in the mixed micellization, which enhances with the increase of the mole fraction of CTAB. The negative magnitudes of indicate the spontaneous formation of mixed micelles between CTAB and SDS. The values of activity coefficients (f1 and f2) were less than unity and the values of the interaction parameter (β) are negative in all cases, which indicate the attractive interaction between CTAB and SDS. The negative values of excess free energy of micellization (ΔGex) signify the stability of the mixed micelles. The negative values of in the chitosan systems indicate that micellization is exothermic. The values of were found to be positive in all cases.

Phase Separation of Amphiphilic Drug Amitriptyline Hydrochloride in the Presence of Additives: Role of Ethanol

In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and 15% w/w) is accounted for in the clouding phenomena of the AMT drug with/without additives (inorganic salts and conventional and gemini surfactants). The critical micelle concentration (cmc) and degree of counterions dissociation (α) of AMT solution at 30 °C in SP buffer (pH 6.7), studied through conductometric studies, are found to be enhanced with the increase in ethanol content due to the reduction in the dielectric constant of mixed media. A dye solubilization study performed under identical physicochemical conditions exhibited supporting results. Clouding could not be observed in 20 wt % EtOH–WR mixed media at pH 6.7. The effects of additives on the CP in 15 wt % EtOH–WR at a pH of 6.95 were also studied. Furthermore, the effect of pH (range 6.7 to 7.15) on the CP in the presence of KCl at the same composition of the mixed media reduce the clouding temperature due to the deprotonation of AMT headgroups. F...

Potentiometric and Conductometric study of complex formations between Norfloxacin and Some metal ions and Norfloxacin determination in Dosage Forms

Potentiometric and Conductometric study of complex formations between Norfloxacin and Some metal ions and Norfloxacin determination in Dosage Forms

Conductometric study of the dissociation behavior of humic and fulvic acids

The dissociation behavior of humic and fulvic acids was characterized on the basis of conductometric measurements. It was confirmed that dissociation is strongly affected by the content of humic or fulvic acids in aqueous solution. In the case of fulvic acids, the dilution effect connected with the increase of dissociation degree and the values of activity coefficients was the main factor influencing their dissociation ability. In the case of humic acids, their aqueous leachates were used and characterized as the main fractions functioning actively in natural systems. These fractions can be rich in acidic functional groups and the chemical compositions of these fractions change with their contents in the leachates. The amount of the dissolved humic fraction, its chemical character and its dissociation ability can be considered to result from equilibrium between dissolved and undissolved humic substances.A maximum was observed for the dependence of the dissociation degree on the concentration of humic leachates. In less concentrated leachates, less soluble humic particles with weaker functional groups were able to be dissolved. The increase of humic contents in leachates caused smaller amounts of soluble fractions with the weakest functional groups to remain in an undissolved form, which led to an increase in the degree of dissociation up to a maximum. In the case of fulvic acids, the dissociation degree increases with decreasing concentration as a result of the dilution. Two different values of pKa were determined for each humic and fulvic sample. The first was determined for higher concentrations, where pKa values are practically constant. The second was the value extrapolated to infinite dilution.

Ultrasonic and conductometric studies of NaCl solutions and study of ionicity of the liquid solution through the Walden plot and various ultrasonic parameters

Ultrasonic velocity, density and viscosity have been measured for aqueous solution of NaCl at different concentrations and at different temperatures, the frequency being maintained at a constant value. These experimental data have been used to estimate the thermodynamic parameters such as Rao’s constant, Wada’s constant, solvation number and surface tension. Electrical conductivity was measured and along with the above parameters was used to study the ionicity of NaCl.

Spectrophotometric and conductometric studies of molecular interaction of brilliant cresyl blue with cationic, anionic and non-ionic surfactant in aqueous medium for application in photogalvanic cells for solar energy conversion and storage

Dye–surfactant interaction in aqueous solutions is of a great importance in technology of dyeing and electrochemical devices such as solar heaters, photovoltaic cell, photogalvanic cell etc. The interaction of the cationic oxazine dye (brilliant cresyl blue, BCB) with anionic (sodium lauryl sulphate, SLS), cationic (hexadecyltrimethylammonium bromide, CTAB) and nonionic (tween 80) surfactants were studied by spectrophotometric and conductometric methods. This study was based on the effect of nature of surfactants on dye–surfactant complex formation. In spectrophotometric study, an absorbance maximum (λmax) for only BCB solution was observed 624.5 nm at lab temperature. The λmax value of BCB was shifted towards higher wavelength (644.5 nm) with SLS and towards lower wavelength (517.5 nm) with tween 80. But, there was no any type of shifting was observed with CTAB. The shifting in λmax value of BCB is due to the complex formation of BCB with SLS and tween 80. These results were supported by conductometric study in which the specific conductance of BCB with SLS and tween 80 mixed solutions were decreased in comparison to sum of individual BCB, SLS or tween 80 while no change was observed with CTAB at 25, 30, and 35 °C. The decrease in specific conductance was caused by the complex formation of slow moving or non-moving larger dye–surfactant complex. The result shows that BCB form complex with SLS and tween 80; however, no complex forms with CTAB. Spectrophotometric study gives information about the stability as well as interaction while conductometric data informs only interaction of BCB with different surfactants. The order of interaction of BCB with different surfactants from both methods are: BCB–tween 80 >BCB–SLS >BCB–CTAB while the order of stability from spectrophotometric method is: BCB–SLS >BCB–CTAB >BCB–tween 80. Therefore, the cationic dye which shows red shift with surfactant might be more useful comparison to which shows blue shift with surfactant for improvement of electrical output of photogalvanic cell. The stability order of dye–surfactants is strongly supported to the order of electrical output of already reported data of photogalvanic cells. Hence, this type of interaction plays an important role for enhancement of electrical output of the photogalvanic cells for solar energy conversion and storage.

Conductometric Study of the Thermodynamics of Micellization of Sodium dodecylsulfate (SDS) in the Presence of Some Aromatic Ammonium Salts

The effect of three organic aromatic salts - Phenyltrimethylammonium (PhTMAB), benzyltrimethylammonium (BzTMAB) and benzyltrimethylammonium (BzTEAB) bromides - on the micellization of sodium dodecylsulfate has been investigated by conductometric method. The critical micelle concentration (CMC) values were found to decrease with increase in the concentration of the aromatic ammonium salts. Thermodynamic parameters of micellization were obtained from CMC measurement in the presence of 0.001 M of the three quaternary aromatic ammonium salts in the temperature range 293-313 K at 5 K intervals. The Gibbs free energy values were generally negative in the presence of the aromatic salts and slightly varied with temperature. The micellization process was both enthalpy and entropy driven. Enthalpy-entropy compensation was observed for all the system with a constant compensation temperature values around 302 K and negative intrinsic enthalpy of compensation.

Effect of the nature of counterion on the micellar properties of cationic surfactants: a conductometric study

ABSTRACTInteraction of cationic surfactants, tetradecyltrimethylammium bromide (TTAB) and tetradecyltrimethylammonium chloride (TTAC) with anionic dye, tartrazine in aqueous solution has been investigated employing conductometric technique. The free energy of transfer of hydrophobic chain, , surface contribution, and their transfer values, and , free energy, , enthalpy, , and entropy, of micellisation have been calculated. A marked decrease in the critical micelle concentration for TTAB compared to TTAC indicates dramatic role of the smaller counterion Br− over the bigger counterion Cl−. Formation of dye–surfactant ion-pairs which behave as nonionic surfactant has been proposed. Higher negative and positive values for TTAB than TTAC are attributed to difference in the size and nature of the counterions Br− and Cl−. Negative and values clearly suggest that micellisation of TTAB and TTAC is thermodynamically spontaneous and exothermic in nature. As ), it suggests that the process of micellisation is entropy dominated for the two surfactants.

Chitosan hydrogel-based electrolyte for clean and biodegradable batteries: energetic and conductometric studies

ABSTRACTMeasurements of voltages generated in clean and biodegradable batteries using lithium-chitosan as electrolyte, carbon and nickel as electrodes, were reported. They produced small amounts of energy providing environment was preserved. The energy smallness was argued by conductivity measurements. The concentration and temperature dependences were undertaken. These measurements were carried out from 0.0005 to 1.0 mol dm−3 in the temperature range 258–323 K, and were compared to glycerol, being clean viscous solvent. The purpose was to substitute toxic solvents currently used, by clean and biodegradable solvents having good performances. The results were analysed with Debye–Huckel–Onsager law at low concentrations and Quasi–Lattice Model at moderate and higher concentrations. The temperature dependence of conductivity was also described using Vogel–Tamman–Fulcher equation. By comparing it to Arrhenius theory, very interesting parameters, such as electrical conductivity infinite dilution, activation energy and Vogel temperature, corresponding to glass transition temperature were extracted from the fit of experimental data.

Spectroscopic and conductometric studies on the interactions of thionine with anionic and nonionic surfactants

In this study, the interaction of thionine, a cationic dye, with anionic [sodium dodecyl sulphate (SDS), lithium dodecyl sulphate (LiDS), and sodium dodecylbenzene sulphonate (SDBS)], nonionic (Tween 20 and Triton X‐100), and binary mixtures of anionic and nonionic surfactants was studied by conductometric and spectrophotometric measurements. The degree of ionisation, the counterion binding parameters, and the equilibrium constants in the premicellar region were obtained from conductivity data. Binding constants of thionine to anionic, nonionic, and mixtures of anionic and nonionic micelles were determined by spectrophotometric measurements. The binding tendency of thionine to anionic micelles followed the order SDBS > SDS > LiDS. The presence of nonionic surfactants increased significantly the binding affinity of thionine to anionic micelles, and the highest binding constant was calculated in the presence of Tween 20. The results obtained from conductometric studies correlated with those obtained from spectroscopic studies. Data concerning dye–surfactant interaction are important for a fundamental understanding of the performance of single and mixed surfactants and for their industrial application.

Conductometric studies of [emim][BF4] and [bmim][BF4] in propan-2-ol. Association of ionic liquids in alcohols

The electrical conductivities of dilute solutions (c<0.004mol∙dm−3) of the ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate [emim][BF4] and 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4] in propan-2-ol have been measured in the temperature range from 283.15 to 318.15K at 5K intervals. The limiting molar conductivities and ionic association constants were calculated using the low concentration Chemical Model (lcCM). Strong ion association was found for the ionic liquids in propan-2-ol within the investigated temperature range. From the temperature dependence of the limiting molar conductivities, the Eyring's activation enthalpy of charge transport was determined. The thermodynamic parameters of ion pair formation such as Gibbs energy, entropy, and enthalpy were evaluated and discussed. The results were discussed and compared with those obtained earlier for other alcohols.

Potentiometric and Conductometric Studies on Complexes of Folic Acid with some Metal Ions

Potentiometric and Conductometric Studies on Complexes of Folic Acid with some Metal Ions

English

English

Conductometric Study of the Interaction of Insecticide Profenofos with Cationic and Anionic Surfactants in Aqueous Medium

Conductometric Study of the Interaction of Insecticide Profenofos with Cationic and Anionic Surfactants in Aqueous Medium

Interaction between antidepressant drug and anionic surfactant in low concentration range in aqueous/salt/urea solution: A conductometric and fluorometric study

Abstract Aqueous/salt/urea micellar solutions of amphiphilic antidepressant drug amitriptyline hydrochloride (AMT) and anionic surfactant sodium dodecylbenzenesulfonate (SDBS) have been examined by conductivity and fluorescence measurements at different temperatures and composition. From the conductometric study, values of critical micelle concentration ( cmc ) of drug have been evaluated and analyzed in terms of effect of surfactant on the hydrophobic nature of AMT–SDBS complex. The values of critical micelle concentration ( cmc ) and other aggregation parameters, micellar mole fraction ( X 1 ) and interaction parameters ( β ) were obtained and discussed in detail. In mixtures of AMT and SDBS, the synergistic interactions in mixed micelles formation increases with the raise in mole fraction of surfactant in absence and attendance of salt/urea. Thermodynamic parameters of the mixtures in aqueous as well as in salt/urea solution have been evaluated by means of a pseudo-phase model. The effect of NaCl shows the salting-out effect, which promotes aggregate formation of AMT and SDBS as well as their mixed systems at lower concentration relative to aqueous solution. The micelle aggregation number ( N agg ) of drug increases with the raise in surfactant mole fraction in mixtures. N agg value of individual and mixed amphiphiles rises in the presence of electrolyte while reduces in the occurrence of urea.

Novel potentiometric sensor for selective monitoring of Ce3 + ion in environmental samples

Novel ligand 1,1′-(pyridine-2,6-diyl)bis(3-(1H-pyrrol-2-yl)prop-2-en-1-one) (L) was synthesised and explored as ion carrier for the selective monitoring of Ce3+ ion in various samples. Spectrophotometric and conductometric studies reveals high affinity of L towards Ce3+ ion and therefore, L was used in the fabrication of poly (vinyl chloride) based membrane sensor of coated graphite electrode (CGE) and coated pyrolytic graphite electrode (CPGE). Best performance was observed with the optimized membrane composition of L: PVC:o-NPOE:NaTPB::7:31:59:3 (w/w, mg). The CPGE exhibits wide working concentration range of (1.9×10−8–1.0×10−1molL−1) and low detection limit of 5.0×10−9molL−1 with Nernstian slope of 19.4±0.2mV−1 decade of activity. The sensor is independent of pH in the pH range of 3.0–8.5 and exhibited fast response time of 9s. The sensor can work satisfactorily in partially non-aqueous media of water-acetonitrile and water-ethanol (30%, v/v) and could tolerate about 20% (v/v) of water-methanol contents. The applicability of the sensor is illustrated by determining Ce3+ ion in real samples and as an indicator electrode in the potentiometric titration of Ce3+ ion with oxalate and fluoride ions.

Micellar aggregation of Triton X-100 surfactant in imidazolium ionic liquids

In this work we investigated aggregation behavior of a nonionic surfactant Triton X-100 in eighteen imidazolium ionic liquids (ILs) with two to eight carbon atoms in cations alkyl chain, namely 1-ethyl-3-methylimidazolium, [EMIM], 1-butyl-3-methylimidazolium, [PrMIM], 3-methyl-1-propylimidazolium, [BMIM], 1-hexyl-3-methylimidazolium, [PMIM], 3-methyl-1-pentyl-imidazolium, [HMIM], and 1-octyl-3-methylimidazolium, [OMIM], and with different anion substituents, such as tetrafluoroborate, [BF4], hexafluorophosphate, [PF6], bis(trifluoromethanesulfonyl)imide, [Tf2N], and trimethylosulfonate, [TfO]. Surface tension, density and dynamic light scattering measurements were conducted to determine surface and micellar behavior of the surfactant in ionic liquids. In addition, conductometric study gave information on an average number of imidazolium cations associating with each oxyethylene unit of the surfactant. An influence of anion and cation species on the ability of ILs to support Triton X-100 micelle formation was stated and discussed in terms of cohesive energy density.