Furfural is classified in organic
compound and has chemical formula OC4H3CHO. It is a
colourless oily liquid that smells like almonds. Furfural turns yellow when
exposed to air. Furfural dissolves in most polar organic solvents, but is only
slightly soluble in water or alkanes. When furfural is heated above 250 °C, it
will be decomposed into furan and carbon monoxide and this reaction can
sometimes be explosive.
Plant materials contains
polysaccharide hemicellulose, a polymer of sugars containing five carbon atoms
each, when heated with sulfuric acid, undergoes hydrolysis to yield these
sugars, mainly xylose. Under the same conditions of heat and acid, xylose and
other five carbon sugars undergo dehydration, losing three water molecules and
C5H10O5 → C5H4O2 + 3 H2O
Furfural is unusually effective as a
solvent for phenolic resins. In the manufacture of abrasive wheels, brake
linings and refractory products for the steel industry, furfural is known as a
reactive solvent and excellent wetting agent.
Furfural is an important renewable,
non-petroleum based, chemical feedstock. Hydrogenation of furfural provides
furfuryl alcohol (FA), which is a useful chemical intermediate and which may be
further hydrogenated to tetrahydrofurfuryl alcohol (THFA). THFA is used as a
non-hazardous solvent in agricultural formulations and as an adjuvant to help
herbicides penetrate the leaf structure.
Refining of lubricating oils &
Furfural has the unique property to
dissolve aromatics and other unsaturated olefins. Furfural is used as a
selective solvent in the refining of lubricating oils. This technology leads to
production of high quality motor oil with improved temperature-viscosity
properties. Aromatics, polar components, mercaptans are removed from petroleum
by means of furfural extraction. Furfural can also be used as decolorizing
agent to refine crude wood rosin.