Glyoxylic acid

• Oxoacetic acid
• Glyoxylic
• Ethanalsäure

• 298-12-4
• 563-96-2 (monohydrate)

Colorless crystals

Fixed

• Semihydrate: 70-75 ° C
• Anhydrous substance: 98 ° C

3:18; 3.32

Readily soluble in water, slightly in ethanol, diethyl ether and benzene

Risk

Template: Infobox chemical / molecular formula search available

Glyoxylic acid (also oxoacetic acid, glyoxylic acid, Ethanalsäure or Oxoethansäure ) consists of an aldehyde and a carboxyl group. It thus represents an intermediate in the oxidation of glycolic acid to oxalic acid out its salts hot glyoxylates.

Occurrence

Glyoxylic acid in young green leaves and immature fruits (especially rhubarb, currants and gooseberries ) included. In glacial acetic acid, glyoxylic acid is also present in small amounts.

Production and representation

For the production of glyoxylic acid or oxalic acid, dichloroacetic acid is hydrolyzed electrolytically reduced. It is also possible the oxidation of glycolic acid or ozonolysis of maleic acid dimethyl ester and subsequent hydrolysis of the resulting methyl glyoxylate methyl hemiacetal. The technical process of ozonolysis of dimethyl maleate proved to be uncontrollable and was discontinued in 2004. The industrially important route to glyoxylic acid is now the oxidation of glyoxal with concentrated nitric acid.

Use

Glyoxylic acid is used for the synthesis of allantoin, antibiotics, chelating agents, pesticides, vanillin, ethyl vanillin and other chemical products. By reaction with cyclohexanone, subsequent dehydration and catalytic dehydrogenation occurs coumaranone 2- ( benzofuran -2 ( 3H)- one), a starting material for the presentation of the fungicide azoxystrobin and strobilurin.

Properties

From an aqueous solution of glyoxylic acid crystallizes as glyoxylic acid hydrate from ( Dihydroxyessigsäure ). This compound represents an exception to the Erlenmeyer rule