Furfural

• Furan- 2-aldehyde
• Fural
• Furan-2- carbaldehyde
• Furancarbonal
• 2- formylfuran
• Furfural

Colorless to light brown coloring liquid with pungent - sweet, bread-like, smell karamellartigem

Liquid

1.16 g · cm -3 ( 20 ° C)

-37 ° C

162 ° C

1.5 hPa ( 20 ° C)

Soluble in water ( 83 g · l-1 at 20 ° C ), ethanol and diethyl ether

1.5261 (20 ° C)

Risk

No classification, as evidence of a carcinogenic effect

65 mg · kg -1 ( LD50, rat, oral)

Template: Infobox chemical / molecular formula search available

Furfural (from the Latin furfur, " bran ", see production), a heterocyclic aldehyde is a colorless, volatile, reddish with light and air exposure to dark brown, toxic oil. It smells striking of bitter almonds and is barely in water, but readily soluble oils and fats; Furfural has a higher density than water.

History

Furfural was first issued in 1831 by the German chemist Johann Wolfgang Dobereiner by the distillation of bran with dilute sulfuric acid. The aldehyde was initially referred to as " furfural "; " Furfural " came into use only after the second world war.

Occurrence

Furfural occurs naturally as a component of essential oils before, for example in cloves and various other plants.

Furfural is formed by heating of carbohydrate- rich foods of mono-and disaccharides on the corresponding 3- Desoxypentosen and together with substituted furfurals volatile main product of the caramelization. Upon further thermal treatment of foodstuffs furfural heterocyclic precursors of important flavor substances ( furan, thiophene derivatives). Furfural readily disproportionates with the formation of furfuryl alcohol and 2- furoic acid ( Cannizzaro reaction).

Extraction

Furfural can be obtained by displacing of the present in many plant materials (e.g. bran) pentoses with sulfuric acid ( dehydration). Also in the pulp production by the magnesium bisulfite, a larger amount of furfural, which can be extracted from the cooking liquor forms. This and because the available derivatives by subsequent reactions ( esp. furan ) furfural wins a role as a renewable resource.

Use

Furfural and the resulting recoverable furan chemistry are of particular interest as an organic raw material and chemical base for syntheses of heterocycles (and thus natural substance, drug, solvent ). It is also used for production of synthetic resins and used as a starting material for synthetic fiber materials.

The reagent is used, among other things, for cleaning of animal and vegetable oils and for the concentration of vitamin A from fish liver oils.

To distinguish between heating oil and diesel fuel, furfural was mixed in Germany since 1976 the oil. Since 2002, EU Solvent Yellow 124 is used as a chemical marker instead.

Safety

Furfural causes already at concentrations of less than 0.1 vol - % strong mucosal secretion, higher concentrations lead to inflammation of the airways and lung. The liquid is absorbed through the skin. Furfural is considered as a substance with reasonable suspicion of carcinogenic potential (Category 3B).