Glyoxal

Glyoxal, also known as ethanedial, is the smallest dialdehyde, with the formula C2H2O2. It is a highly reactive chemical that is typically handled and stored as aqueous solutions; pure glyoxal is a hygroscopic, unstable liquid that rapidly hydrates and can polymerize.

In solution, glyoxal exists mainly in hydrated forms and can undergo further condensation reactions. It readily reacts with nucleophiles such as amines and diols, forming imines or crosslinked products. Its reactivity makes it useful as a chemical intermediate and crosslinking agent.

Production and occurrence: Glyoxal is produced industrially by oxidation of ethylene glycol and can be generated as a byproduct in various oxidation processes. Because of its tendency to hydrate and polymerize, commercial glyoxal is typically supplied in stabilized aqueous solutions.

Applications: Glyoxal is used as a crosslinking agent for polymers, proteins, cellulose, and other materials. It is employed in the manufacture of resins and in textile and paper finishing. In histology, stabilised glyoxal formulations are used as fixatives, offering an alternative to formaldehyde in some contexts. It also serves as a precursor in organic synthesis for dyes, pigments, and heterocyclic compounds.

Safety and handling: Glyoxal solutions are corrosive and can irritate the skin, eyes, and respiratory tract. It can act as a skin sensitizer and poses inhalation hazards. The substance polymerizes in storage, so stabilizers are used and storage is typically in well-ventilated areas away from bases and strong nucleophiles. Appropriate PPE and fume-hood use are advised.