Sodium oleate is the sodium s alt of oleic acid. Let's reveal the main physical and chemical properties of this compound, its areas of application.
Physical properties
Sodium oleate has a melting point of 220 degrees Celsius. Under normal conditions, it is a white or slightly yellowish powder, which is highly soluble in water, as well as in hot ethyl alcohol. Sodium oleate is insoluble in ether and acetone (ketone). This compound is included in modern detergents and soaps.
Sodium oleate has a hydrophobic effect. It can be explained by the formation of calcium soaps with alkaline components of the material.
Getting options
How is sodium oleate obtained? The inorganic compound that is the basis for its formation is sodium hydroxide. S alt is formed by the chemical interaction of alkali with oleic (organic) acid. This reaction is reversible; therefore, concentrated sulfuric acid is used to shift the equilibrium towards the formation of reaction products. It attracts water molecules because it is hygroscopic.
Featuresproperties
What characterizes sodium oleate? The properties of this compound are divided into three groups:
- Colligative. They depend on the number of molecules. These include pressure, decrease or increase in temperature, volume.
- Additive. They are due to molecular forces, expressed as the sum of the properties of the groups of atoms that make up the molecules.
- Constructive. These properties include the color of the compounds, the dipole moment.
Sodium oleate is a colloidal surfactant. It contains eighteen carbon atoms, which form a stable dispersed system of a heterogeneous type. This chemical compound, according to the classification associated with the chemical structure, is an anionic surfactant. This substance has a washing effect, belongs to the fourth group according to the classification of P. A. Rebinder. The washing effect is associated with the contact between an aqueous solution of a given s alt and the surfaces of solids. Solubilization, characteristic of sodium oleate, is the main component in the complex of its washing action.
Micelle formation is a spontaneous process. For him, the magnitude of the change in the Gibbs energy has a negative indicator.
Application
Where is sodium oleate used? The use of this compound as an emulsifier is based on its good solubility in water. It can be used to obtain stable oil-water emulsions. After the introduction of calcium cations into the resulting solution, precipitation of insoluble oleate is observed,changing the picture to the reverse process.
Due to the presence of an organic fragment in the s alt molecule, adsorption occurs on the surface of benzene. After introducing a dye into the emulsion, for example, Sudan III, soluble in aromatic benzene, the dispersion medium and phase can be identified.
When treated with sodium oleate, the wettability of quartz and its electrokinetic potential are significantly reduced. Let us analyze the water-sodium oleate system. The value of the surface tension of the s alt leads to a shift in the region of inactivity in the direction of higher concentration. This emulsifier in high concentration has a direct effect on foam stability.
In the surface layer, the concentration of this substance exceeds this indicator in its volume by tens of thousands of times. Magnetic treatment of an aqueous solution of a given s alt affects its sorption properties.
Contact with sodium oleate of various minerals that are in a magnetic suspension leads to a decrease in the heat of wetting, a decrease in the optical density of the solution.
Summing up, let's say that among the main areas of application of this organic s alt, it is necessary to note the introduction into the composition of soap. It is the hydrophobic properties of sodium oleate that have made it a popular ingredient in the cosmetics industry. Colloidal chemistry, in which this compound is in demand, explains the physical and chemical characteristics of inorganic and organic solutions, the specifics of their practical application.
