What Is Stearic Acid?
➤Stearic acids are one of the foundations of the cosmetic industry. She took part in the formation of soap liquid and solid form. The esters of stearic acid receive their use in the surfactants, which means that reduce the surface tension, and thereby help to not segregate a mixture, be it a suspension or emulsion. Such substances which help to connect two incompatible phase medium in the system are referred to as emulsifiers or excipients. By emulsifiers, it is possible to build creams of different origin oil/water or water/oil phase respectively and the environment.
The stearic acid is also applicated in some industries, such an example is that of luxury candles. For greater rigidity of lipsticks and lip balms. Melting point: 55-65 °C (for use with stearic acid is always necessary heating) for cosmetics additions.
Stearic Acid is a Monobasic Acid.
Which means that in a composition having a carboxyl group. Name stearic acids is treviаl, nomenclature IUPAC is octadecanoic acid. This acid has an organic, saturated and has the connections between the carbon atoms are simple – sigma.
Stearic acid structure.
The general formula of stearic acid: Cn H2n+1 COOH
Its molecular formula: C17 H35 COOH
And its molecular mass: 284 g / cm3
Of organic acids of fatty character are characteristic following constants:
Boiling point: 361 °C
Melting point: 69,3 °С
density: 0.9408 g / cm 3
The appearance of stearic acid.
Physical state: solid, powder.
The acid was n- chain. It has no branches in the carbon-carbon coupling. Carboxyl group at the end of the bond. The counting always starts from the end of the carboxyl group, which serves in the naming of the compound.
The reactions in which it is possible to take part in stearic acid are just a substituent and decomposition. Accordingly, the connection is not possible because of saturation and.
Chemical properties of stearic acid.
Chemical properties of stearic acid are typical of acids from organic nature: (dissociation).
Hidroxonion ions determine the acidity of the solution. Because of their availability, the litmus indicator displays the color red. Mr.(molecular weight) gives the hydrogen cation, who joined the water becomes when radical is a smaller molecular weight as the larger molecular weight of the acid easier exhibits and basic properties. Because of the intensity of the carbonyl group by the radical.
The reaction of stearic acid with sodium hydroxide results in the formation of a salt of stearic acid known as sodium stearate and water was formed. The sodium stearate used in the production of soaps. Soaps of sodium are solid, and those with potassium liquid.
The reaction is not called neutralization, although like her, and saponification. They are unidirectional and proceeds to the end.
The reaction of stearic acid with alcohol is called esterification. Esterification may be reversible flow over the middle. If the medium is the acidic reversible reaction in the basicity of the medium the reaction is unidirectional. The reverse reaction of the esterification process is called hydrolysis. During hydrolysis, the ester is dissolved in water.
Because of the acidic nature, which is due to the carboxyl group is optionally reacting with ammonia. In the reaction of the acid with ammonia to form an amide and water was formed.
Stearic acid participates in the combustion reaction. The combustion reaction is a decomposition of the stearic acid to carbon dioxide and water, separated and energy.
Author. Nidelina Petkova