Furfural (or furfuraldehyde) is produced commercially by the acid hydrolysis of pentosan polysaccharides from non-food residues of food crops and wood wastes. produced from fibrous residues of food crops, oats are often the raw material used. Precursors of furfural are the pentosans xylan and arabinan, pentosan content of the raw material is important and must be between 25 - 40%. Furfural is viscous, colorless liquid that has a pleasant aromatic odor; upon exposure to air it turns dark brown or black. It boils at about 160°C. 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 commonly used as a solvent; it is soluble in ethanol and ether and somewhat soluble in water. Furfural is the aldehyde of pyromucic acid; it has properties similar to those of benzaldehyde. A derivative of furan, it is prepared commercially by dehydration of pentose sugars obtained from cornstalks and corncobs, husks of oat and peanut, and other waste products. The major application of furfural is being use as a feedstock for furfuryl alcohol production, most of which is used in the production of furan resins which in turn are used to produce foundry sand binders. Furfural is also used as a solvent for refining lubricating oils, butadiene extraction and the furfural-based production of tetrahydrofuran. Tetrahydrofuran is used as a commercial solvent and is converted in starting materials for the preparation of nylon.
Furfural is used in the manufacture of furan, an intermediate in the synthesis of pharmaceuticals, agricultural chemicals, stabilizers and fine chemicals, it is also used in the manufacture of furfuryl alcohol, methylfuran and nitrofurans which are intermediates for making antimicrobial agents. Furan is a family of organic compounds of the heterocyclic aromatic series characterized by a five-membered ring consisting of four CH2 groups and one oxygen atom. The simplest furan family is furan itself; a clear, volatile and mildly toxic liquid; melts at -86 C, boils at 32 C, insoluble in water, soluble in alcohol and ether. It is used as a chemical intermediate and solvent. It is converted by hydrogenation to tetrahydrofuran, which is more important solvet. Its unhindered oxygen atom carries two unshared pairs of electrons - a structure which favors the formation of coordination complexes and the solvation of cations.