Sodium sulfate
[CAS# 7757-82-6]

Identification

• Classification: API >> Digestive system medication >> Laxative antidiarrheal
• Name: Sodium sulfate
• Molecular Formula: Na₂SO₄
• Molecular Weight: 142.04
• CAS Registry Number: 7757-82-6 (15124-09-1)
• EC Number: 231-820-9
• SMILES: [O-]S(=O)(=O)[O-].[Na+].[Na+]

Properties

• Density: 2.68
• Melting point: 884 °C
• Boiling point: 1700 °C
• Water solubility: 18.5 mg/L

Safety Data

• Safety Statements: S24/25

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin sensitization	Skin Sens.	1	H317
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411

Discovery and Applications

The discovery of sodium sulfate is attributed to German-Dutch chemist Johann Rudolf Glauber. Glauber discovered sodium sulfate in mineral waters near Nauheim, Germany in 1625 and called it "sal mirabilis" or "wonderful salt" for its medicinal properties. Sodium sulfate occurs naturally in mineral deposits such as Glauber's salt (hydrated form) and the anhydrous form, thenardite. Chemically, sodium sulfate consists of two sodium ions (Na?) and one sulfate ion (SO4²?). It is highly soluble in water, forming a white crystalline solid.

Sodium sulfate is widely used as a filler and processing aid in laundry detergents and laundry soaps. It acts to enhance the texture and flow of detergents, making them easier to handle and dissolve. It also helps to dilute the active ingredients, ensuring effective cleaning action while reducing production costs. In the glass industry, sodium sulfate is used as a flux to remove small bubbles and impurities from molten glass, improving its clarity and quality. This makes it essential for the production of high-quality glass for windows, containers, and various other applications. In the textile industry, sodium sulfate is used in dyeing processes to promote uniform absorption of dyes. It acts as a leveling agent, ensuring that dye is evenly distributed throughout the fabric, resulting in consistent color and improved fabric quality. Sodium sulfate plays an important role in the kraft process of papermaking, where it helps remove lignin from wood pulp, producing a stronger, whiter paper. It is also used in certain types of pulp bleaching processes, helping to improve the overall efficiency and quality of paper products. In chemical synthesis, sodium sulfate is used as a drying agent for organic solvents and as a reactant in various chemical processes. Its stability and non-reactivity make it suitable for different industrial reactions and product formulations.

Sodium sulfate is used in certain desalination processes to help separate salt from water. It is also used in wastewater treatment to help remove pollutants and improve water quality. In agriculture, sodium sulfate is sometimes used to correct sodium-deficient soils and strengthen soil structure. Its application helps to increase the water holding capacity and nutrient availability of the soil, promoting healthier plant growth.

Historically, sodium sulfate was used as a laxative because of its ability to draw water into the intestines, promoting bowel movements. Although modern laxatives have largely replaced it, sodium sulfate is still occasionally used in traditional medicine. Sodium sulfate has been used in some cases to treat dehydration. It releases water as it dissolves to help rehydrate patients and maintain electrolyte balance.

Sodium sulfate is used to teach concepts related to crystallization, solubility, and ionic compounds. Its ease of use and clear crystal formation make it an ideal substance for classroom demonstrations and laboratory experiments. Sodium sulfate is used as a standard reagent in a variety of chemical analyses and experiments. Its effectiveness as a desiccant and compatibility with many solvents make it valuable in research and analytical chemistry.

References

1979. Absorption, serum levels and urinary excretion of inorganic sulfate after oral administration of sodium sulfate in the conscious rat. Biochimica et Biophysica Acta (BBA) - General Subjects.
DOI: 10.1016/0304-4165(79)90039-4

1991. Secondary structure perturbations in salt-induced protein precipitates. Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology.
DOI: 10.1016/0167-4838(91)90226-p