Furfural

Structural formula
General
Surname	Furfural
other names	Furan-2-aldehyde; Fural; Furan-2-carbaldehyde; Furan carbonal; 2-formylfuran; Furfural;
Molecular formula	C 5 H 4 O 2
Brief description	colorless, slightly brown liquid with a pungent, sweet, bread-like, caramel-like odor
External identifiers / databases
EC number	202-627-7
ECHA InfoCard	100.002.389
PubChem	7362
Wikidata	Q412429
properties
Molar mass	96.08 g mol −1
Physical state	liquid
density	1.16 g cm −3 (20 ° C)
Melting point	−37 ° C
boiling point	162 ° C
Vapor pressure	1.5 h Pa (20 ° C)
solubility	soluble in water (83 g l −1 at 20 ° C); soluble in ethanol and diethyl ether ;
Refractive index	1.5261 (20 ° C)
safety instructions
H and P phrases	H: 226-301-312-330-315-319-351-335
	P: 210-280-302 + 352-304 + 340-305 + 351 + 338-310
MAK	No classification, as there is a suspicion of a carcinogenic effect; Switzerland: 2 ml m −3 or 8 mg m −3 ;
Toxicological data	65 mg kg −1 ( LD 50 , rat , oral )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Furfural (from Latin furfur , bran) is a volatile, colorless, reddish to dark brown, poisonous oil with a bitter almond odor when exposed to light and air . It is hardly soluble in water, but easily soluble in oils and fats. It belongs to the heterocyclic aldehyde class . Since it can be produced entirely from renewable raw materials and is an important building block in synthesis, it has great potential as a platform chemical .

history

Furfural was first obtained in 1831 by the German chemist Johann Wolfgang Döbereiner by distilling bran with dilute sulfuric acid. The aldehyde was initially referred to as furfural, the name furfural only became established after the Second World War .

Occurrence

Furfural comes naturally as a component of essential oils e.g. B. in cloves and various other plants.

Furfural is formed when foods rich in carbohydrates are heated from mono- and disaccharides via the corresponding 3-deoxypentoses and, together with substituted furfurals, is the main volatile product in caramelization . In the case of further thermal treatment of food, furfural is the precursor for important heterocyclic flavoring substances such as furan and thiophene derivatives. Furfural disproportionates easily with the formation of furfuryl alcohol and 2-furancarboxylic acid ( Cannizzaro reaction ).

Extraction

Furfural is obtained by the action of sulfuric acid on the pentoses contained in many plant materials (e.g. corn cobs or bagasse ) in a dehydration process . Also in the pulping after the magnesium bisulfite process, a larger amount of furfural that can be extracted from the cooking liquor forms. Furfural can therefore be obtained entirely from renewable raw materials.

use

Furfural and the furan that can be obtained from it are of particular interest as an organic raw material and chemical base for syntheses in heterocycles - and thus also natural products , pharmaceuticals and solvent chemistry . Numerous compounds can be made from furfural, so it has great potential as a platform chemical.

It is also used for the production of synthetic resins and as a raw material for synthetic fibers .

As a reagent, it is used, among other things, to clean animal and vegetable oils and to concentrate vitamin A from fish liver oils.

To differentiate between heating oil and diesel fuel , furfural was added to heating oil in Germany from 1976. Since 2002, Solvent Yellow 124 has been used as a chemical marker throughout the EU .

Furfural is also used to make furan resins .

Safety instructions / risk assessment

Furfural already causes strong mucosal secretion at concentrations of less than 0.1% by volume, higher concentrations lead to inflammation of the airways and pulmonary edema. The liquid is also absorbed through the skin. Furfural is considered a substance with a justified suspicion of carcinogenic potential (category 3B).

Furfural was included by the EU in 2017 in accordance with Regulation (EC) No. 1907/2006 (REACH) as part of substance evaluation in the Community's rolling action plan ( CoRAP ). The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. The uptake of furfural was caused by concerns about worker exposure , high (aggregated) tonnage and widespread use, as well as the possible dangers of carcinogenic and mutagenic properties. The reassessment is scheduled for Denmark from 2021.

Web links

Entry on furfural . In: P. J. Linstrom, W. G. Mallard (Eds.): NIST Chemistry WebBook, NIST Standard Reference Database Number 69 . National Institute of Standards and Technology , Gaithersburg MD
Entry furfural at Chemicalland21.com

Individual evidence

↑ ^a ^b ^c ^d ^e Entry on furfural. In: Römpp Online . Georg Thieme Verlag, accessed December 10, 2014.

↑ ^a ^b ^c ^d ^e ^f ^g ^h Entry on 2-furaldehyde in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .

↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-266.

↑ Entry on 2-furaldehyde in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

↑ Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 98-01-1 or furfural ), accessed on November 2, 2015.

^ Entry on furfural in the ChemIDplus database of the United States National Library of Medicine (NLM) .

^ ^A ^b Joseph J. Bozell & Gene R. Petersen: Technology development for the production of biobased products from biorefinery carbohydrates — the US Department of Energy's “Top 10” revisited . In: Green Chemistry . tape 12 , no. 4 , 2010, p. 525-728 , doi : 10.1039 / b922014c .

↑ Review article: AV Wacek I .: Furfurol. In: Angewandte Chemie. 54, 1941, pp. 453-458, doi : 10.1002 / anie.19410544302 . A. v. Wacek: Furfural. Addendum. In: The chemistry. 55, 1942, pp. 30-30, doi : 10.1002 / anie.19420550305 .

↑ ^a ^b Oliver Türk: Material use of renewable raw materials. Springer Vieweg, Wiesbaden, 2014, ISBN 978-3-8348-1763-1 , pp. 443-454.

↑ Sustainability in the Lenzing Group - Cellulose Production ( Memento of the original from March 26, 2006 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2
↑ DIN 51426.
↑ Arne Gardziella: Furan Resins (FF). In: Wübrand Woebcken (ed.): Kunststoffhandbuch (= Duroplaste. Volume 10). 2nd completely revised edition, Hanser Verlag, Munich, 1988, ISBN 978-3-446-14418-7 , pp. 70–84.

↑ Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): 2-furaldehyde , accessed on March 26, 2019.

[Römpp-1] Entry on furfural. In: Römpp Online . Georg Thieme Verlag, accessed December 10, 2014.

[GESTIS-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h Entry on 2-furaldehyde in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .

[CRC90_3_266-3] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-266.

[CLP_100.002.389-4] Entry on 2-furaldehyde in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[5] Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 98-01-1 or furfural ), accessed on November 2, 2015.

[ChemIDplus-6] Entry on furfural in the ChemIDplus database of the United States National Library of Medicine (NLM) .

[Bozell-7] A ^b Joseph J. Bozell & Gene R. Petersen: Technology development for the production of biobased products from biorefinery carbohydrates — the US Department of Energy's “Top 10” revisited . In: Green Chemistry . tape 12 , no. 4 , 2010, p. 525-728 , doi : 10.1039 / b922014c .

[8] Review article: AV Wacek I .: Furfurol. In: Angewandte Chemie. 54, 1941, pp. 453-458, doi : 10.1002 / anie.19410544302 . A. v. Wacek: Furfural. Addendum. In: The chemistry. 55, 1942, pp. 30-30, doi : 10.1002 / anie.19420550305 .

[Türk-9] Oliver Türk: Material use of renewable raw materials. Springer Vieweg, Wiesbaden, 2014, ISBN 978-3-8348-1763-1 , pp. 443-454.