Furfurol, also known as furilic aldehyde, furfural or 2-furancarboxydehyde, is a heterocyclic compound with a molecular brute formula: C5H4O2. Furfural is a colorless, volatile and chemically unstable liquid as it tends to oxidize and resinify.
Furfural is a biochemical synthesis product found in nature. It is contained in some products, and with reference to the weight of dry substance we find it in: corn cobs, 23.4%; oat shells, 22.3%; exhausted olive pomace, 16.0%; bagasse of sugarcane, 17.4%; bagasse di sorghum (Algeria), 15.9%; rice husk, 11.4%.
In the industrial furfishing extraction process, values between 55 and 65% of the analytical content are reached.
Given the application and use of furfural for various applications in this compound is extracted from various products or by-products, as raw materials of agricultural waste; among these you can extract furfural from the rice husk and from exhausted pomace with autoclave processes. Other industrial processes have however been put in place for the useful extraction of furfural from other products.
One of the main applications and therefore uses of furfural is that which sees it used as a selective solvent for lubricating oils in the petrochemical industry, or as a raw material for furfuryl phenolic resins and other chemicals.
The first use in this sense was in the purification of rosin. Dark products, and therefore not very valuable, are dissolved in petrol and treated with furfural. By heating, a homogeneous solution is obtained, which by cooling is divided into two layers; in the furfurol layer the coloring substances are contained. The superior solution, distancing the solvent by distillation, gives a much clearer and more precious product than the original one.
More recently, furfural has also been used in the treatment of other oil fractions, for example to purify products intended to power cracking plants.
In the last war, furfural was used for the production of butadiene-based synthetic rubber. In fact, butadiene can be produced by cracking refinery gases containing 4-carbon hydrocarbons. However, for the transformation into synthetic rubber it is necessary to have butadiene with 98.5 ÷ 99.5% purity. In the cracking, on the other hand, butylenes are formed together with butadiene, which are difficult to remove; the separation, however, can be done easily enough by performing a fractional distillation of the mixture in a rectification column in which the furfural which is acting as a selective solvent is entered from above and appreciably changes the relative volatility of the components.
Furfural is also used, due to its solvent properties, in the treatment of semi-drying or drying vegetable oils. In fact, by treating the solutions of such oils in gasoline with furfural, the glycerides of the acids containing two or more double bonds are preferably extracted. Thus a semi-drying oil can be divided into two fractions consisting of a drying oil and a non-drying oil respectively.
Finally, due to its high solvent power, furfural is also used as a “paint stripper” to remove old layers of paint.
Warning: The information reported is not medical advice and may not be accurate. The contents are for illustrative purposes only and do not replace medical advice.