Similarly, p, values were found to increase with increasing temperature at any concentration of the solution. It is also found that the p, values increase with the chain length of the fatty acids and this may be due to the hydrophobic characters of alkyl chain.
The phenomena of solute-solvent interaction
It was also found to depend on the distance of closest approach of ions in ion pairs. The Na ion behaves as a large ion as the Kd of Bu4N and Na iodides are found to be of the same order.
Factors affecting viscosity
Since most of the time the molecules in a gas fly freely through the void, anything that increases the number of times one molecule is in contact with another will decrease the ability of the molecules as a whole to engage in coordinated motion. This is because the adhesive forces between the water and the glass are strong enough to pull the water molecules out of their spherical formation and hold them on the surface of the glass, thus avoiding repulsion between similar molecules.
Properties of alcohol
Oxidation of 1-propanol with Na2Cr2O7 and H2SO4 gives only a 36% yield of propanaldehyde and oxidation with chromic acid gives propanoic acid. 1-Propanol is thought to be similar to ethanol in its effects on the human body, but 2-4 times more potent.
Surfactant
However, at fairly well-defined concentrations, a sudden change occurs in various physico-chemical properties such as viscosity, osmotic pressure, turbidity, electrical conductivity and surface tension. In this research, sodium dodecyl sulfate (SDS) was used to find out the change of various physico-chemical properties of the investigated solutions.
Laurie Acid
The apparent molar volumes, the apparent molar expansivities, the viscosities of lauric acid in proanol and in surfactant-assorted propanol to understand the solution behavior are of interest to this study, which is of industrial and biochemical importance.
Palmitic acid
Various physicochemical properties of palmitic acid in solution can provide important evidence in biological, pharmaceutical and many other systems. The apparent molar volumes, the apparent molar expansivities, the viscosities of palmitic acid in propanol and in propanol with a surfactant to understand the dissolution behavior are of interest in this thesis and are of industrial and biochemical importance.
Stearic acid
An additive property is a property that, for a given system, is the sum of the corresponding properties of its constituents. Purely constitutive properties: The property, which depends entirely on the arrangement of the atoms in the molecule and not on their number, is called a purely constitutive property.
Molarity
For example, the optical activity is the property of the asymmetry of the molecule and occurs in all compounds with an overall asymmetry. Colligative properties: A colligative property is one that depends primarily on the number of molecules involved and not on their nature and size.
Molar volume of Mixtures
The apparent molar volume of a solute in solution, generally denoted by cot and is defined by the relation [21]. For binary solution, the apparent molar volume () of an electrolyte in an aqueous solution is given by [22], . III and 112 are the number of moles, M1 and M2 are molar masses of the solvent and solute, respectively, and p is the density of the solution.
The partial molarity of a solute is defined as the change in property when one mole of the solute is added to an infinite amount of solvent, at constant temperature and pressure, so that the concentration of the solution remains practically unchanged. If 'Y' represents the partial molarity of a binary solution at constant temperature and pressure, then Y will be a function of two independent variables n1 and fl2, representing the number of moles of the two components present. The usefulness of the concept of partial molarity lies in the fact that it can be shown mathematically as, .
The concentration dependence of the apparent molar volume of electrolytes has been described by the Massoii equation [25], the Redlich-Mayer equation [27] and the Owen-Brinkley equation [26]. Masson [25] found that the apparent molar volume of electrolytes varies with the square root of the molar concentration as, .
K NY(100URT
Different thermodynamic parameters
Many studies have been devoted to measuring and predicting the density and viscosity of biodiesel fuel as a function of temperature. The most important of these relies on the accurate knowledge of the properties of pure compounds. Behavior in solution of compounds with asymmetric carbon atoms [56] in amino acids in water and in guanidine hydrochloride, in relation to denaturation [57] of proteins and their denaturation in urea [58, 59] and ionic hydration volumes in relation with solution properties and ion adsorption [60] were successfully studied by one or more of the above methods.
Recently, an increasing attention has been paid to studies of the effects of organic additives on micellization processes in non-aqueous solutions [61-64]. In particular, increasing interest is being focused on studies of the incorporation or dissolution of alcohols, which play a very important role in the preparation of microemulsions [65-67]. Furthermore, fatty acids are also found in living systems where they are free to participate in the pathway of phospholipid biosynthesis and cell fat storage.
It appears that there is an open door for the study of the phase behavior of fatty acid salts that has been neglected in the past. The effect of SDS on the self-association processes of alcohol and the properties of the solution has been investigated for various systems using a variety of techniques [85-87].
Aim of the research
Experimental
- Apparatus Ite
- Preparation and Purification of Reagents
- Distillation of water
- Chemicals
- Preparation of solution
- Density measurement
- Apparent Molar Volumes measurement
- Determination of Thermodynamic Parameters
The densities of the solutions were determined by weighing a certain volume of the solution in a pycnometer at the specified temperature. As the solution began to gain bath temperature, excess liquid was drained through the capillary. The difference between the two weights (weight with solution and without solution) gave the weight of the solution in the density bottle.
The inside of the viscometer was thoroughly cleaned with hot chromic acid and then with distilled water, so that there was no obstruction in the capillaries and the liquid could flow freely without leaving any drop behind. The viscometer was then clamped vertically in the thermostatic water bath so that the top mark of the top bulb was well below the water level. Using pipette filler attached to the narrower limb of the viscometer, the water was aspirated above the top mark of the bulb.
The reading at each temperature was repeated three or four times or even more, in order to check the reproducibility of the flow time, keeping the temperature at the same value. Since the exact viscosity and density of water at different temperatures are known (from the literature), the calibration constant A of the viscometer for different temperatures is obtained using the equation,.
Results and Discussion
Cll 0.785
- Apparent molar volumes
It is seen that the apparent molar volume depends on the fatty acid concentration as well as the temperature. Apparent molar volumes of all fatty acids in propanol were found to increase with concentration at all temperatures. Similarly, the values were found to increase with increasing temperature at each solution concentration.
The values were also found to increase with the length of the fatty acid chain and this may be due to the hydrophobic character of the alkyl chain towards the CH3CH2- group of propanol. Figures 4.16-4.18 show plots of apparent molar volumes, c°t, against the square root of the concentration of various fatty acids in propanol at various temperatures. The figures also show plots of apparent molar volumes, q 1 , against the square root of the concentration of various fatty acids in propanol at a given temperature with very few exceptions that may be due to experimental error.
The increase in apparent molar volumes of various fatty acids in propanol in the presence of surfactant supports those of the density values as previously discussed. These results can be explained in terms of the establishment of additional hydrophobic interactions between the hydrophobic moieties of the surfactant, fatty acids and propanol.
Thermodynamic Properties
Thermodynamic properties, free energy, AG*, enthalpy change, AI1*, and entropy, AS* for viscous flow were calculated from viscometric data. AG* values are positive for all studied systems indicate that the studied systems are non-spontaneous, i.e., work must be done to overcome the energy barrier for the viscous flow process as shown in Table 4.11-4.13. AII* values are positive for all systems studied indicating that work must be done to overcome the energy barrier for the flow process, as shown in Table 4.14-4.16.
The value of entropy of activation, AS* of the investigated systems is shown in table 4.14-4.16. Negative values of the mixtures indicate that they are more ordered or structured than the pure propanol.
Conclusion
F Viscosity of aqueous fluoride and sodium periodate solutions ionic energies and entropies of activation for viscous flow" J. In Liquid Fuels and Industrial Products from Renewable Resources, Proceedings of the Third Liquid Fuel Conference", Nashville, TN. F Solubility of 1-hexanol in aqueous solutions of sodium dodecyl sulfate at pressures up to 140MPa.
Partial Molar Volumes, Compressibilities, and Partition Coefficients" Langmuir, Just Accepted Manuscript, Publication Date (Web): 18 Jun 2014. P A critical assessment of micellization of sodium dodecylbenzenesulfonate (SDBS) and its interaction with poly(vinylpyrrolidone) and hydrophobically modified polymers" , J. E Apparent molar volume, apparent molar adiabatic compressibility and solubilization studies of aqueous solutions of sodium p-(n-dodecyl)benzenesulfonate as a function of surfactant and solubilization concentrations and temperature”, J.
34;Effect of viscosity and interfacial tension of surfactant-polymer flooding on oil recovery in high-temperature, high-salinity reservoirs", J.
