Chemical Raw Materials Encyclopedia: Physical Properties And Industrial Applications of Glacial Acetic Acid (GAA)

Glacial acetic acid, chemically known as acetic acid, is commonly referred to in the industrial sector as industrial glacial acetic acid or GAA (Glacial Acetic Acid), with the CAS number 64-19-7. As one of the most important organic acids, glacial acetic acid holds a pivotal position in the national economy and the chemical industry chain. An in-depth understanding of its physical properties and industrial applications is of great guiding significance for chemical industry practitioners and participants in related supply chains.

In terms of physical properties, pure glacial acetic acid is a colorless, transparent, hygroscopic liquid with a strong, pungent, and sour odor. Its molecular formula is C₂H₄O₂, and its molecular weight is 60.05. The most prominent physical characteristic of glacial acetic acid is its freezing point, which is approximately 16.6°C to 16.7°C. This means that in cooler room temperatures, high-purity acetic acid easily solidifies into colorless crystals resembling ice, which is the origin of the name "glacial acetic acid." Additionally, glacial acetic acid has a relatively high boiling point, typically between 117°C and 118°C, and a flash point of about 39°C to 57°C, classifying it as a flammable and corrosive hazardous chemical. In terms of solubility, glacial acetic acid exhibits excellent water solubility and can mix with water, ethanol, ether, and benzene in any proportion, but it is insoluble in carbon disulfide. It is worth noting that the density of glacial acetic acid is slightly greater than that of water, with a relative density of approximately 1.05. Furthermore, mixing it with water at specific concentrations results in volume contraction and an increase in density.

Regarding industrial applications, glacial acetic acid is an extremely important basic chemical raw material with a vast downstream industry chain. First and foremost, it serves as a fundamental precursor for synthesizing numerous high-value-added chemicals. It is extensively used to produce vinyl acetate monomer (VAM), acetic anhydride, acetate esters (such as ethyl acetate and butyl acetate), and chloroacetic acid. These derivatives are further processed into cellulose acetate, coatings, adhesives, and various synthetic resins, which are widely applied in the textile, building materials, and packaging industries.

Secondly, glacial acetic acid plays a crucial role in the pharmaceutical, agrochemical, and dye industries. It is not only a core raw material for synthesizing common drugs like aspirin and various acetate-based medications, but it is also frequently used as a reaction medium, solvent, or washing agent in complex organic synthesis reactions. In the production of agrochemicals and dyes, glacial acetic acid equally provides indispensable acidic environments or reactive functional groups.

Furthermore, glacial acetic acid finds broad applications in light industry and the manufacturing of daily consumer goods. Although industrial-grade glacial acetic acid is strictly prohibited for food use due to impurities and heavy metals, strictly purified food-grade glacial acetic acid is an essential ingredient for synthesizing edible vinegar, food flavorings, beverage acidulants, and preservatives. In the textile dyeing and rubber industries, it is used as an auxiliary agent for neutralizing residual alkalis, preventing color bleeding, and treating fabric stains. In electroplating processes, it can also serve as a weakly acidic buffer in steps such as zinc and nickel plating.

In summary, relying on its unique physicochemical properties, glacial acetic acid (GAA) has become a critical hub connecting basic chemicals with numerous end-use application fields. However, due to its strong corrosiveness and irritancy, strict adherence to safety regulations, including sealed ventilation and personal protective measures, must be maintained during industrial production, storage, and transportation to ensure its safe and efficient service to the modern industrial system.