colourless to reddish-brown oily liquid with almond odour
Vapor may irritate eyes and respiratory system. Liquid irritates skin and may cause dermatitis.
Special Hazards of Combustion Products: Irritating vapors are generated when heated
In the manufacture of furfural-phenol plastics such as Durite; in solvent refining of petroleum oils; in the preparation of pyromucic acid. As a solvent for nitrated cotton, cellulose acetate, and gums; in the manufacture of varnishes; for accelerating vulcanization; as insecticide, fungicide, germicide; as reagent in analytical chemistry. In the synthesis of furan derivatives.
Furfural is unstable to air, light and acids. Impurities include formic acid, .-formylacrylic acid and furan-2-carboxylic acid. Distil it in an oil bath from 7% (w/w) Na2CO3 (added to neutralise acids, especially pyromucic acid). Redistil it from 2% (w/w) Na2CO3, and then, finally fractionally distil it under vacuum. It is stored in the dark. [Evans & Aylesworth Ind Eng Chem (Anal ed) 18 24 1926.] Impurities resulting from storage can be removed by passage through chromatographic grade alumina. Furfural can be separated from impurities other than carbonyl compounds by the bisulfite addition compound. The aldehyde is steam volatile. It has been purified by distillation (using a Claisen head) under reduced pressure. This is essential as is the use of an oil bath with temperatures of no higher than 130o which is highly recommended. When furfural is distilled at atmospheric pressure (in a stream of N2), or under reduced pressure with a free flame (caution: because the aldehyde is flammable), an almost colourless oil is obtained. After a few days and sometimes a few hours, the oil gradually darkens and finally becomes black. This change is accelerated by light and occurs more slowly when it is kept in a brown bottle. However, when the aldehyde is distilled under vacuum and the bath temperature kept below 130o during the distillation, the oil develops only a slight colour when exposed to direct sunlight during several days. The distillation of very impure material should NOT be attempted at atmospheric pressure; otherwise the product darkens very rapidly. After one distillation under vacuum, a distillation at atmospheric pressure can be carried out without too much decomposition and darkening. The liquid irritates mucous membranes. Store it in dark containers under N2, preferably in sealed ampoules. [Adams & Voorhees Org Synth Coll Vol I 280 1941, Beilstein 17/9 V 292.]
ChEBI: An aldehyde that is furan with the hydrogen at position 2 substituted by a formyl group.
Colorless or reddish-brown mobile liquids with a penetrating odor. Flash points 140°F. Denser than water and soluble in water. Vapors heavier than air. May be toxic by ingestion, skin absorption or inhalation.
Air & Water Reactions
Flammable. Furfural is sensitive to light and air. Soluble in water, with mixing.
Furfural is a colourless to amber-like oily liquid with an almond-like odour. On exposure
to light and air, it turns reddish brown. Furfural is used in making chemicals,
as a solvent in petroleum refining, a fungicide, and a weed killer. It is incompatible with strong acids, oxidisers, and strong alkalis. It undergoes polymerisation on contact
with strong acids or strong alkalis. Furfural is produced commercially by the acid
hydrolysis of pentosan polysaccharides from non-food residues of food crops and wood
wastes. It is used widely as a solvent in petroleum refining, in the production of phenolic
resins, and in a variety of other applications. Human exposure to furfural occurs during
its production and use, as a result of its natural occurrence in many foods and from the
combustion of coal and wood.
Furfural is an essential renewable, non-petroleum based, chemical feedstock which is primarily composed of various agricultural byproducts, including oat husks, wheat bran, corncobs, and sawdust. Chemically, furfural is an organic compound belonging to an aldehyde of furan with the odor of almonds. It is typically produced for industrial purposes, which can be used as a selective solvent in the process of refining lubricating oils and used in the manufacture of transportation fuels to improve the characteristics of diesel fuel and catalytic cracker recycle stocks. Besides, furfural is applied widely for producing resin-bonded abrasive wheels and purifying butadiene needed for the manufacture of synthetic rubber. It is also used to make other furan chemicals, such as furoic acid and furan itself. Other products of furfural include weed killer, fungicide, other solvents and etc.
Furfural reacts with sodium hydrogen carbonate. Furfural also can react with strong oxidizers. An exothermic resinification of almost explosive violence can occur upon contact with strong mineral acids or alkalis. Furfural forms condensation products with many types of compounds, including phenol, amines and urea. .