A study on Volumetric and Viscometric Properties for the Mixtures of DMF and Other Alcohols from Temperatures ranges 303.15K to 323.15K

Densities, p, and viscosities, ?, of four binary systems: N,N-dimethyl formamide (DMF) + 1-propanol, DMF + 2-propanol, DMF + butanol and DMF + 1-pentanol have been measured at five different temperatures ranging form 303.15K to 323.15K at an interval of 5K. Excess molar volumes were found to be negative over the entire concentration ranges. The negative excess molar volume decreases with the increase of chain length of alcohol, the magnitude follows the order DMF+ 1-propanol >, + 2-propanol >, +butanol >, + 1-pentanol. The change of viscosity has been found to be sensitive to the chain length of alcohols. Excess viscosities and Grunberg- Nissan interaction parameters have been found to be positive for DMF + 1-propanol and DMF + 2-propanol systems, and negative for other two systems DMF + butanol and DMF + 1-pentanol. The thermodynamic energy of activation; such as, positive ?G#E each also compatible with the observation.

Effect Of Sodium Dodecyl Sulfate On Viscometric Properties Of Methanol, Ethanol, n-Propanol And iso-Propanol At Different Temperatures

The critical micelle concentration (CMC) of Sodium Dodecyl Sulfate (SDS) in water was determined from the conductance and viscosity measurement. The estimated value of CMC was found to be 0.0085 mol.L-1 at 29°C. The concentration of SDS in pre-micellar and post-micellar region of 0.005M and 0.01M, respectively were used for the viscometric measurements of Methanol, Ethanol, n-Propanol, iso-Propanol at different temperatures. Viscosities of ternary mixtures of Methanol, Ethanol, n- Propanol and iso-Propanol in 0.005M and 0.01M aqueous SDS have been studied over the entire range of composition at 298.15- 323.15K with an interval of 5K except Methanol. Methanol system was studied at 298.15-308.15K owing to its low boiling point. Viscosities increase rapidly with alcohol concentration and show maxima in aqueous SDS rich region at 0.2 – 0.3 mole fraction of alcohols. The position of maxima virtually does not change remarkably with the variation of temperature. The excess viscosities, ?E values are found to be positive and large in magnitude, indicating that aqueous SDS solutions of alcohols are highly non ideal. The heights of the maxima are in the order:iso-Propanol + aqueous SDS > n-Propanol + aqueous SDS > Ethanol + aqueous SDS > Methanol + aqueous SDS.The excess viscosities, ?E data have been fitted by the least square method to the four parameter Redlich-Kister equation and the values of the parameter aj have been reported. Journal of Bangladesh Chemical Society, Vol. 25(2), 110-123, 2012 DOI: http://dx.doi.org/10.3329/jbcs.v25i2.15046

A Study of Some Physical Properties for Binary System of Cyclohexane with n-decane and 1-pentanol at Different Temperatures

mixtures of cyclohexane + n-decane and cyclohexane + 1-pentanol have been measured at 298.15, 308.15, 318.15, and 328.15 K over the whole mole fraction range. From these results, excess molar volumes, VE , have been calculated and fitted to the Flory equations. The VE values are negative and positive over the whole mole fraction range and at all temperatures. The excess refractive indices nE and excess viscosities ?E have been calculated from experimental refractive indices and viscosity measurements at different temperature and fitted to the mixing rules equations and Heric – Coursey equation respectively to predict theoretical refractive indices, we found good agreement between them for binary mixtures in this study. The variation of these properties with composition and temperatures of the binary mixtures are discussed in terms of molecular interactions.