How is sodium oleate used?

Sodium oleate is the sodium salt of oleic acid. We reveal the basic physical and chemical properties of this compound, the field of its 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.

Options for obtaining

How is sodium oleate obtained? The inorganic compound, which is the basis for its formation, is sodium hydroxide. Salt is formed by the chemical interaction of alkali with oleic (organic) acid. This reaction is reversible, so concentrated sulfuric acid is used to shift the equilibrium toward the formation of reaction products. It draws water molecules, because it is a hygroscopic substance.

Property Features

What is characterized by sodium oleate? The properties of this compound are divided into three groups:

• The 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 a sum of properties of groups of atoms that are part of the molecules.
• Constructive. These properties include the color of the compounds, the dipole moment.

Sodium oleate is a colloidal surfactant. It consists of eighteen carbon atoms, which form a stable dispersed system of a heterogeneous type. This chemical compound is classified as anionic surfactant by classification related to its chemical structure. This substance has a detergent effect, it belongs to the fourth group according to PA classification. Rebinder. The detergent effect is related to the contact between the aqueous solution of this salt and the surfaces of solids. Solubilization, characteristic of sodium oleate, is the main term in the complex of its detergent action.

Micelle formation is a spontaneous process. For him, the magnitude of the change in Gibbs energy has a negative exponent.

Application

Where is sodium oleate used? The use of this compound as an emulsifier is based on its good solubility in water. With its help, it is possible to obtain stable emulsions of the oil-water type. After introduction of calcium cations into the resulting solution, precipitation of insoluble oleate, which changes the picture to the reverse process, is observed.

Due to the presence of an organic fragment in the molecule, adsorption on the benzene surface takes place. After the dye is introduced into the emulsion, for example, Sudan III, soluble in aromatic benzene, it is possible to detect the dispersion medium and the phase.

When treated with sodium oleate, the wettability of quartz, its electrokinetic potential, is significantly reduced. Let us analyze the water-oleate system of sodium. The value of the surface tension of the salt leads to a shift in the region of inactivity in the direction of greater concentration. This emulsifier in high concentration has a direct effect on the stability of the foam.

In the surface layer, the concentration of this substance exceeds this figure in its volume by tens of thousands of times. Magnetic treatment of an aqueous solution of this salt affects its sorption properties.

Contact with sodium oleate of various minerals that are in the magnetized suspension leads to a decrease in the heat of their wetting, a decrease in the optical density of the solution.

To summarize, let's say that among the main areas of application of this organic salt is the introduction to soap. It is the hydrophobic properties of sodium oleate that made it a sought-after component in the cosmetic industry. Colloid chemistry, in which this compound is claimed, explains the physical and chemical characteristics of inorganic and organic solutions, the specificity of their practical application.