cas number glacial acetic acid

Understanding Glacial Acetic Acid CAS Number and Its Applications

Glacial acetic acid, known chemically as ethanoic acid, is a clear, colorless liquid with a pungent smell that many recognize as the characteristic scent of vinegar. Its chemical formula is C2H4O2, and it has a CAS number of 64-19-7. The term glacial refers to its state at or below 16.6 °C (62 °F), where it becomes a solid—a crystalline form that resembles ice. This identity as a pure form of acetic acid distinguishes glacial acetic acid from the diluted forms commonly used in culinary applications.

Chemical Properties and Characteristics

Glacial acetic acid is a weak organic acid, which means that it only partially dissociates into ions in solution. Despite being classified as weak, it is still a powerful solvent and reagent due to its ability to participate in various chemical reactions. It has a melting point of 16.6 °C, a boiling point of 118 °C, and a density of about 1.05 g/cm³. It is hygroscopic, meaning it can absorb moisture from the air, and is completely miscible with water, alcohols, and ethers.

This acid is characterized by its acidity, which can be attributed to its ability to release protons (H+) into solution, thereby affecting pH. Its structural formula showcases a carboxyl group (-COOH) that is responsible for its acidic properties. In terms of safety, glacial acetic acid is considered corrosive, requiring proper handling, storage, and usage protocols to mitigate the risks associated with exposure.

Industrial Applications

Glacial acetic acid plays a vital role in various industrial processes. It is primarily utilized as a solvent and a chemical reagent in the production of synthetic fibers, plastics, and other chemical compounds. One of its most significant applications is in the manufacture of acetate esters, which are used as solvents and in the production of inks, paints, and coatings.

Moreover, glacial acetic acid serves as a key intermediate in the production of various chemicals such as

1. Acetic Anhydride Used in the synthesis of cellulose acetate, a valuable polymer in the production of photographic film and coatings. 2. Vinyl Acetate Important in making polyvinyl acetate (PVA), which is used in adhesives, paints, and as a clear finish for wood. 3. Sodium Acetate Used in food preservation and as a buffer in biochemical research.

Additionally, glacial acetic acid finds its place in the food industry, albeit in its diluted form. It is commonly used as a preservative and flavoring agent in various food products.

Laboratory Uses and Reactions

In the laboratory, glacial acetic acid is frequently employed as a reagent in various chemical reactions. It is used for synthesizing esters through a reaction with alcohols, which is usually catalyzed by an acid catalyst. This process is vital in producing fragrant compounds used in perfumes.

Furthermore, glacial acetic acid can participate in condensation reactions, such as the formation of anhydrides, esters, and acetamides. It can also act as a solvent for various organic reactions, making it an invaluable substance for chemists.

Environmental and Safety Considerations

While glacial acetic acid has a multitude of uses, it is essential to handle it with care. Exposure can cause severe burns on contact with skin and can be harmful if inhaled or ingested. Proper personal protective equipment (PPE), including gloves and goggles, should be worn when handling this chemical. Furthermore, it should be stored in a cool, dry place away from incompatible substances, such as strong oxidizing agents.

From an environmental perspective, glacial acetic acid has a relatively low toxicity to aquatic life but can contribute to the acidification of water bodies if released in large quantities. Therefore, regulations are in place to ensure responsible management of this chemical.

Conclusion

Glacial acetic acid, with its CAS number 64-19-7, is a significant industrial chemical with diverse applications spanning multiple industries. Its chemical properties enable a wide array of reactions, making it indispensable in both manufacturing processes and laboratory settings. While its corrosive nature necessitates careful handling and adherence to safety guidelines, its benefits in industry and research cannot be overstated. Understanding glacial acetic acid is essential for anyone engaged in chemistry or industries that utilize this versatile compound.