Glyoxal

Description

Glyoxal, the simplest dialdehyde, was first prepared by N. Lubawin in 1875, when he oxidized acetaldehyde with HNO3?or H2SeO3. The HNO3?method is still used commercially, along with metal-catalyzed gas-phase oxidation of ethylene glycol. At low temperatures, glyoxal forms yellow crystals; it melts at 15 °C and boils at 51 °C. Its low flash point (–4 °C) makes its green vapor explosive in air. It’s used chiefly in paper coating and textile finishing processes.

Chemical properties

colourless or light yellow liquid

The Uses of Glyoxal

Glyoxal is used in the production of textilesand glues and in organic synthesis.

The Uses of Glyoxal

Glyoxal is used to prepare 4,5-dihydroxy-2-imidazolidinone by condensation with urea. It finds application in leather tanning process, textile finishes and paper coatings. It is an important building block in the synthesis of imidazoles. It acts as a solubilizer and cross-linking agent in polymer chemistry. Further, it is used as a fixative for histology to preserve cells in order to examine under a microscope.

The Uses of Glyoxal

ermanent-press fabrics; dimensional stabilization of rayon and other fibers. Insolubilizing agent for compounds containing polyhydroxyl groups (polyvinyl alcohol, starch, and cellulosic materials); insolubilizing of proteins (casein, gelatin, and animal glue); embalming fluids; leather tanning; paper coatings with hydroxyethylcellulose; reducing agent in dyeing textiles.

What are the applications of Application

Glyoxal, 40 % Solution is used to denature nucleic acids by forming stable complexes with guanine residues

Definition

ChEBI: Glyoxal is the dialdehyde that is the smallest possible and which consists of ethane having oxo groups on both carbons. It has a role as a pesticide, an agrochemical, an allergen and a plant growth regulator.

General Description

Yellow crystals melting at15°C. Hence often encountered as a light yellow liquid with a weak sour odor. Vapor has a green color and burns with a violet flame.

Air & Water Reactions

Mixtures with air may explode. Polymerizes quickly on standing, or on contact with a trace of water (possibly a violent reaction), or when dissolved in solvents containing water, [Merck, 502(1968)]. Soluble in water. An aqueous solution contains mono molecular Glyoxal. [Hawley]

Reactivity Profile

Glyoxal reacts vigorously with strong oxidizing agents such as nitric acid. Polymerizes rapidly even at low temperature if anhydrous [Noller]. Aqueous solutions are more stable but also polymerize on standing. Reacts with itself in the presence of base to give glyconates. Undergoes addition and condensation reactions that may be exothermic with amines, amides, aldehydes, and hydroxide-containing materials. Mixing in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: chlorosulfonic acid, oleum, ethyleneimine, nitric acid, sodium hydroxide [NFPA 1991].

Hazard

Mixture of vapor and air may explode. Questionable carcinogen.

Health Hazard

Glyoxal is a skin and eye irritant; the effectmay be mild to severe. Its vapors are irritatingto the skin and respiratory tract. Anamount of 1.8 mg caused severe irritation inrabbits’ eyes. Glyoxal exhibited low toxicityin test subjects. Ingestion may cause somnolenceand gastrointestinal pain.
LD50 value, oral (guinea pigs): 760 mg/kg.

Health Hazard

Inhalation causes some irritation of nose and,40% solution throat. Contact with liquid,40% solution irritates eyes and causes mild irritation of skin; stains skin yellow. (No information available on symptoms of ingestion.)

Fire Hazard

Behavior in Fire: Heat may cause polymerization to a combustible, viscous material.

Flammability and Explosibility

Not classified

Safety Profile

Low toxicity by SYN: AEROTEX GLYOXAL 40 ingestion and skin contact. A skin irritant. A powerful reducing agent. May explode on contact with air. Polymerizes violently on contact with water. During storage it may spontaneously polymerize and ignite. Reacts violently with chlorosulfonic acid, ethylene imine, HNO3, oleum, NaOH, can cause violent reactions. Can explode during manufacture. When heated to decomposition it emits acrid smoke and irritating fumes. See also ALDEHYDES.

Waste Disposal

Glyoxal is mixed with a combustible solventand burned in a chemical incineratorequipped with an afterburner and scrubber.