What is the Difference Between Sodium Lauryl Sulfate and Ammonium Lauryl Sulfate

The main difference between sodium lauryl sulfate and ammonium lauryl sulfate is that sodium lauryl sulfate is less soluble in water, while ammonium lauryl sulfate is more soluble in water.

Sodium lauryl sulfate and ammonium lauryl sulfate are two types of surfactants. Surfactants are organic compounds that have the ability to lower the surface tension between two different compounds. They are amphiphilic molecules with a hydrophobic tail and hydrophilic head. The hydrophobic part repels water, while the hydrophilic part attracts water. The hydrophobic part can either be a fluorocarbon, siloxane, or hydrocarbon, whereas the hydrophilic head is electrically charged positively, negatively, or neutrally. According to the type of charge in the hydrophobic head, there are four types of surfactants: anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Both sodium lauryl sulfate and ammonium lauryl sulfate fall under the category of anionic surfactants.

Key Areas Covered

1. What is Sodium Lauryl Sulfate 
      – Definition, Structure, Solubility 
2. What is Ammonium Lauryl Sulfate
      – Definition, Structure, Solubility 
3. Difference Between Sodium Lauryl Sulfate and Ammonium Lauryl Sulfate
      – Comparison of Key Differences

Key Terms

Ammonium Lauryl Sulfate, Sodium Lauryl Sulfate

What is Sodium Lauryl Sulfate

Sodium lauryl sulfate is a surfactant with the chemical formula C₁₂H₂₅NaO₄S. It is also known as dodecyl sulfate. It is the sodium salt of lauryl sulfate (SLS). Sodium lauryl sulfate is a white or creamy-colored powder or crystal with a molecular weight of 288.38. Moreover, its melting point is 206^°C, while the boiling point is 288.4°C. Its density is 1.1 g/cm³, while the solubility is 100 g/L. It is naturally extracted from coconut and or palm kernel oil. It usually consists of a mixture of sodium alkali sulfates, mainly lauryl.

Sodium lauryl sulfate is an anionic surfactant. Sodium lauryl sulfates lower the surface tension of aqueous solutions. There are many uses and applications of this chemical. It is widely used in surfactants as cleaning products, personal care products, and cosmetics. There are high concentrations of sodium lauryl sulfate in industrial products such as car wash products and floor cleaners. It is also useful in pharmaceuticals, toothpaste, cleaning products, fat emulsifiers, detergents, and wetting agents. This chemical is also found to have some microbicidal activity. Another use of this chemical is as a research tool in protein biochemistry. However, sodium lauryl sulfate may cause skin irritations. The intensity of the irritation depends on the level and duration of exposure to the chemical.

What is Ammonium Lauryl Sulfate

Ammonium lauryl sulfate is a fat-based organic molecule. It is also known as ammonium dodecyl sulfate. Ammonium lauryl sulfate is a more complex molecule with a heavier molecular mass and larger size in comparison to sodium lauryl sulfate. The molecular weight of ammonium lauryl sulfate is 283.43 g/mol, while its density is 1.02 g/cm³. Moreover, the boiling point of ammonium lauryl sulfate is 418 °C. This anionic compound also contains a non-polar hydrocarbon chain and a polar sulfate end. 

Ammonium lauryl sulfate is used in a variety of materials, including toothpaste, cleansers, and shampoos. In fact, this chemical compound is responsible for the foaming in toothpaste and shampoos. It is relatively cheap in cost.

Difference Between Sodium Lauryl Sulfate and Ammonium Lauryl Sulfate

Definition

Sodium lauryl sulfate is an anionic surfactant with the chemical formula C₁₂H₂₅NaO₄S whereas ammonium lauryl sulfate is an anionic surfactant with the chemical formula C₁₂H₂₉NO₄S.

Structure

Sodium lauryl sulfate has a sodium ion in its structure, while ammonium lauryl sulfate has an ammonium ion in its structure.

Solubility

Sodium lauryl sulfate is less soluble in water, while ammonium lauryl sulfate is more soluble in water.

Size and Weights

Sodium lauryl sulfate is small and lightweight, whereas ammonium lauryl sulfate has a comparatively larger size and a heavier weight.

Conclusion

In brief, surfactants are organic compounds with molecules having a hydrophobic tail and a hydrophilic head. They reduce surface tension and aid in cleaning substances. Sodium lauryl sulfate and ammonium lauryl sulfate are two types of anionic surfactants. The main difference between sodium lauryl sulfate and ammonium lauryl sulfate is their solubility; sodium lauryl sulfate is less soluble in water, while ammonium lauryl sulfate is more soluble in water.

Reference:

1. “Ammonium lauryl sulfate solution.” National Library of Medicine. 
2. “Sodium Lauryl Sulfate.” ChemSpider.

Image Courtesy:

1. “Sodium dodecyl sulfate” By Calvero. – Selfmade with ChemDraw. (Public Domain) via Commons Wikimedia
2. “Ammonium dodecyl sulfate” By Ed (Edgar181) – Own work (Public Domain) via Commons Wikimedia