Glyoxal


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glyoxal

[glī′äk‚sal]
(organic chemistry)
(CHO)2 Colorless, deliquescent powder or liquid with mild odor, melting point 15°C, boiling point 51°C; used to insolubilize starches, cellulosic materials, and proteins, in embalming fluids, for leather tanning, and for rayon shrinkproofing.

Glyoxal

 

the simplest dialdehyde, OHC—CHO. In the crystalline and liquid states it is yellow; the vapor is green. Melting point, 15° C; boiling point, 50.4° C; density, 1.4 g/cm3 (20° C); index of refraction nD20.5 1.3826.

Glyoxal is prepared by dehydrogenation of ethylene glycol, HOCH2—CH2OH, over a copper catalyst or by treating tetrachloroethane, Cl2CH—CHCl2, with oleum, followed by hydrolysis of the resultant glyoxal sulfate,

Glyoxal is readily soluble in water, alcohol, and ether; it polymerizes readily during storage, particularly in the presence of traces of water. Polymeric glyoxal can be de-polymerized to the monomeric form by distilling over phosphorus pentoxide. In the presence of alkali it undergoes the intramolecular Cannizzaro reaction, yielding glycolic acid. Treatment with ammonia gives imidazole, and with aromatic o-diamines it gives pyrazine derivatives.

References in periodicals archive ?
Kinetics of glycoxidation of bovine serum albumin by methylglyoxal and glyoxal and its prevention by various compounds.
The latter may react with singlet oxygen to produce dioxetane 91 as a precursor of oxalic acid (HOOC-COOH), glycolaldehyde 92, and glyoxal 93, all of which are known products of glycoxidation [95].
Particularly, CML could be formed by the reaction of glucose and other sugars and glyoxal with amino groups of arginine and lysine or by lipids peroxidation [55].
Further the property of gelatin film can improve by the chemical treatment, for example films reticulated with formaldehyde and glyoxal have higher tensile strengths, opacity, lower water vapor permeability, and good color differences than the untreated films [121].
Antibacterial properties of honey are the result of the low water activity causing osmosis, chelation of free iron, its slow release of hydrogen peroxide, high acidity, and the antibacterial activity of methyl glyoxal.
However, the commercially prepared reagents have different reactivities because different products or geometric isomers are formed from the addition of urea, formaldehyde and glyoxal.
glyoxal, methylglyoxal) and the free amino groups of amino acids, peptides and proteins [1].
Mark Henning, global general manager for Dow Microbial Control, commented that "During the past few years, formulators have increasingly made and sold products that are supposedly glutaraldehyde-based, but actually contain other ingredients, including formaldehyde and glyoxal .
One of the most promising approaches to fighting cancer revolved around the Carbonyl group - Glyoxal and Methylglyoxal.
In addition to the pathway involving Amadori products, several AGEs are formed independently by direct binding of reactive carbonyl compounds (RCCs), including glyoxal, methyglyoxal, and 3-deoxyglucosone (3DG), preferentially on arginine residues of proteins, generating hydroimidazolones as byproducts (6).
For instance, histochemical methods relying on the Karnovsky and Roots cholinesterase method to localize endplates (57) and the glyoxal bis-(2 hydroxyanil) (GBHA) (58) or von Kossa (59) methods to localize [Ca.
NTB may result from the Maillard reaction, however in this case the amino acids react with nonsugar carbonyl compounds, such as diacetyl, glyoxal or methylglyoxal.