Stearic Acid

Introduction

Stearic acid is present in the fats of animals and plants and used in food products that help treat or reduce eczema symptoms, skin inflammation and help retain the skin's moisture. Cosmetics products including stearic acid must be used after consulting a skin doctor or dermatologist to avoid the side effects like irritation, rashes, or severe cream burn on skin.

What is Stearic acid?

The saturated long-chain fatty acid is made up of 18 backbone of carbon and is referred to as stearic acid. The acid can be found in several types of fats of plants and animals. Stearic acid is determined as the major source of cocoa butter and shea butter.

Figure 1 − Structure of Stearic acid

The acid is highly utilized in the production of several materials that are necessary for everyday life. The material includes detergents, soaps, and cosmetics such as shampoos and shaving cream. The molecular formula of the acid can be written as $\mathrm{CH_{3}(CH_{2})_{16}COOH}$.

Production of Stearic Acid

Stearic acid can be easily derived from shea butter and coconut oil which provides a moisturizing effect on layers of skin. Stearic acid has an appearance of a white solid with a mild smell that floats on water as its solubility rate in water is less. Stearic acid also has several side effects including severe irritation in the skin, respiratory tract, eyes, and damage in eyes of humans. The acid can also be denoted by other names after production in labs such as Octadecanoic acid, 57-11-4, Stearophanic acid, and n-Octadecanoic acid.

The structure of stearic acid includes an 18-carbon backbone that remains attached to a saturated long fatty acid chain.

Stearic acid is a chemical compound that is combustible in nature. The acid is naturally non-toxic to humans but excessive use of the compound can lead to irritation in the throat, nose, and eyes. C18H36O2 which is generally obtained from octadecane is used in plant metabolite, an algal metabolite, a Daphnia Magna metabolite, and human metabolite. The acid remains in a solidified form that has an appearance of white colour with a mildly pungent and oily smell.

Figure 2 − Production of Stearic acid

Production of Stearic acid, Public Domain, Wikimedia Commons

Stearophanic acid is produced through the saponification of triglycerides in the presence of hot water at the temperature of 100°C. This acid's mixture is distilled, including palmitic acid and stearic acid. The acid can also be derived biosynthetically from carbohydrates by fatty acid machinery synthesis. Nearly 28–45% of stearic acid is present in shea butter and cocoa butter.

Properties of Stearic Acid

The chemical and physical properties of stearic acid are stated below.

Properties of Stearic Acid
Chemical formula	$\mathrm{C_{18}H_{36}O_{2}}$
Boiling point	361°C
Molecular weight	284.484 g/mol
Melting Point	69.3°C
Density of Stearic acid	0.9408 g/cm3
Solubility	Stearic acid shows less water solubility. stearic acid is moderately soluble in alcohols. The acid is soluble in carbon tetrachloride, carbon disulfide, and methyl formate or methyl methanoate. Stearic acid shows solubility in dichloromethane under ambient temperature.
Other names of Stearic acid	Octadecanoic acid, 57-11-4, Stearophanic acid, and nOctadecanoic acid.

Uses of Stearic acid

Some common uses of stearic acid are stated below.

• Stearic acid is used widely in several medical, chemical, and cosmetic industries across the world. The materials that include stearic acid include detergents, soaps, and cosmetics products like shampoos and shaving cream.

• The acid can also be included in the production of products like candles, oil pastels and hard candies.

• According to U.S Food and Drug Administration (FDA) it can be stated that stearic acid is quite safe as a food additive that is often consumed through chocolates made up of cocoa butter.

• Stearic acid is utilized as a lubricating agent and food additives.

• The acid is widely used in manufacturing of pharmaceuticals.

• $\mathrm{C_{18}H_{36}O_{2}}$ is used in plant metabolite, an algal metabolite, a Daphnia magna metabolite, and human metabolite.

• Stearic acid also has the ability of skin moisturizing, softening and smoothing that are included in products of face cream, moisturizing cream and face wash.

• Cocoa butter, shea butter, and animal fat which contains stearic acid are the major sources of emollient and natural cleanser.

• Stearic acid can also be used for manufacturing of insulators.

• The acid is widely utilized in food packaging industry.

Conclusion

The IUPAC name of stearic acid is determined as octadecanoic acid which is the useful kind of saturated fatty acid obtained from vegetable and animal oil or fats. The acid can also be referred to as a waxy solid and is widely used in the production of wax, oil pastels, moisturizing cream, soaps, and detergents. The molecular formula of stearic acid is denoted as $\mathrm{CH_{3}(CH_{2})_{16}COOH}$ which has a density rate of 0.9408 g/cm3.

FAQs

1. Which are the foods that have a high rate of stearic acid?

The foods in which stearic acid is highly found include dairy products, fish, poultry, meat, and grains. This acid is also found in fat-rich products like cocoa butter which is consumed as chocolate and in mutton tallow, beef tallow, lard, and butter.

2. What are the major benefits of Stearic acid?

The major benefits of stearic acid include skin moisturizing, softening and smoothing. The acid also acts as a surfactant as it is used as an emulsifier for thickening and improving the texture of the products.

3. What are the side effects of stearic acid?

Stearic acid can be easily obtained from shea butter and coconut oil which provides a moisturizing effect on human skin. Apart from this, stearic acid also has various side effects including severe irritation in the skin, respiratory tract, eyes, and damage in eyes of humans.