Furfural Meaning

Furfural is an organic compound obtained during the dehydration of sugars. Its IUPAC name is furan-2-carbaldehyde. The word, furfural comes from the Latin word furfur that stands for bran, its usual source. Sugars present in a variety of agricultural byproducts such as corn cobs, oats, wheat bran, and sawdust are used to produce furfural. It is commonly used in many processed foods and beverages.


Furfural is a colourless liquid that darkens on exposure to air. It is the best-known member of the furan family. Furfural meaning is furfuraldehyde or also called 2-furaldehyde. It is also an important source of other furans. The boiling point of furfuraldehyde is 161.70C. The furfural structure is given below:

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Furfuraldehyde

The chemical formula for furfuraldehyde or furfural aldehyde is C4H3O-CHO. In 1922, Quaker Oats company started producing furfural from oat hulls for commercial use much after its discovery by a German scientist Johann Wolfgang in 1821. The industrial development of the production of furfural is a great example of how industries utilize agricultural residues. The major raw material source of furfural such as corncobs, oat hulls, cottonseed hulls, rice hulls, and bagasse are replenished annually ensuring a constant supply of raw material for the production of furfural.


In large rotary digesters, lots of raw material and dilute sulphuric acid are steamed under pressure. The furfural form is continuously removed with steam and then concentrated with the help of distillation. The furfural obtained by distillation separates into two layers of condensation and the wet furfural at the bottom is dried with the help of vaccum distillation to obtain furfural with a minimum of 99% purity. Given below is the dehydration reaction of pentoses under an acid catalyst.

C5H10O5 C5H10O2 + 3H2O

The furfural price remains stable in the market and is readily available at Furfural sigma Aldrich. Global demands of furfural remain high with China as its leading production capacity of 85% and consumption of 75%.


Properties of Furfural

Furfural has a molecular weight of 96.08 g/mol. It is denser than water and water-soluble. Its vapours are heavier than air. It has a distinct caramel taste and smells somewhat like benzaldehyde. It has a boiling point of 161.70C. It is considered a major platform chemical that is used in the production of various other chemicals. 


Furfural strongly resembles benzaldehyde in its reactions as an aldehyde. In the presence of strong aqueous alkali, it undergoes a Cannizaro reaction. It dimerizes furoin under the influence of potassium cyanide and by the action of ammonia is converted into hydro furamide  (C4H3O-CH)3N2.


On exposure to air at room temperature, furfural degrades into formic acid and formerly acrylic acid. Furoic or furfural acid is a crystalline solid, white in colour, and is used as a bactericide and a preservative. Its esters are fragrant liquids commonly used in perfumes and flavourings.


Methyl Furfural

5-methyl 2-furaldehyde is an arenecarbaldehyde that is slightly soluble in water and is used as a food flavouring agent. It is also used as a fragrance agent for in-home products or similar industrial products.


Hydroxymethyl Furfuraldehyde

5-hydroxy methyl furfural is an organic compound obtained upon dehydration of sugars, which is highly soluble in water and organic solvents.  It is used as an additive agent in the food industry and also in the production of various fuels and chemicals. It is absent in fresh food but is naturally generated upon heating of sugar-containing food items.


Conclusion

Furfural is one of the furan derivatives from hemicellulose present in lignocellulosic. It is naturally obtained upon dehydration of xylose, which is a pentose sugar. This heterocyclic and aromatic aldehyde consists of an aldehyde side group and a furan ring. It is a colourless liquid and has an oily appearance with an almond-like odour. Furfural has various industrial purposes being a platform chemical that is used in the production of various other chemical compounds. It is also used in the production of furan compounds. 

FAQs (Frequently Asked Questions)

Question 1: What are the Various Furfural Uses?

Ans- Owing to its distinct properties, furfural finds a variety of uses. It is a specialized chemical solvent and is an important renewable feedstock that is converted into many useful solvents, polymers, fuels, and useful chemicals by using catalytic reduction.

  • It is used as a solvent in the refining of lubricating oils and rosin.

  • It improves the properties of diesel fuel and catalytic cracker recycle stocks.

  • It is commonly used in the manufacture of resin-bonded abrasive wheels and in the purification of butadiene required for the production of synthetic rubber.

  • Furfural is an important source of hexamethylenediamine which is used in the manufacturing of nylon.

  • Furfural-phenolic resins obtained on condensation with phenol are of various uses.

  • Furfural alcohol formed by passing furfural and hydrogen vapours over a copper catalyst at an elevated temperature is used in the plastic industry for the production of corrosion-resistant cement and cast-moulded items.

Question 2: Explain Some of the Reactions Associated With Furfural.

Ans- Furfural is a heterocyclic aldehyde that is used as a raw material in the production of various furan-based chemicals such as methyl furan, furfuryl alcohol, tetrahydrofurfuryl alcohol, tetrahydrofuran, furoic acid, dihydropyran, etc. It has two major functional groups, an aldehyde and two olefin groups making it a versatile compound to be used for many applications. 


Reactions such as acylation, acetylation, reductive amination, reduction to alcohols, decarboxylation, oxidation to carboxylic acids, Grignard reaction, and aldol reaction occur through the aldehyde functional group. Reactions such as alkylation, hydrogenation, oxidation, halogenation, open ring reactions, and nitration are carried out through the furan ring system. 

  • Furfural undergoes an oxidation reaction to convert into furoic acid.

  • It undergoes hydrogenation to produce furfuryl alcohol.

  • It forms 2-Methyl furan during decarbonylation.

  • Furfural upon hydrogenation performs tetrahydrofuran.

  • It undergoes reductive amination to form furfuryl amine.

  • On decarboxylation, furfural converts into furan.