Abstract

Furan is a 5-membered heterocyclic, oxygen-containing, unsaturated ring compound. From a chemical perspective it is the basic ring structure found in a whole class of industrially significant products. The furan nucleus is also found in a large number of biologically active materials. Compounds containing the furan ring (as well as the tetrahydrofuran ring) are usually referred to as furans. From a manufacturing standpoint, however, furfural is the feedstock from which all of the commercial furan derivatives are derived, as it the easiest and least expensive to manufacture. Furan is produced from furfural commercially by decarbonylation; loss of carbon monoxide from furfural gives furan directly. Tetrahydrofuran is the saturated analogue containing no double bonds. This article is limited primarily to simple furans in which the nucleus occurs as a free monocycle, and, in general, does not include compounds in which the furan ring is fused to another ring. Tetrahydrofuran is produced commercially from furfural by decarbonylation followed by hydrogenation; it is also produced by several different methods from other raw materials.

Furfural and furfuryl alcohol are specialty solvents. They also are reactive solvents and contribute low viscosity to resin formulations. Thermosetting resins containing furfural and/or furfuryl alcohol “furan resins” demonstrate specialty properties including corrosion resistance, high carbon yield, stability at elevated temperature, low fire hazard, and excellent physical strength. These properties are of industrial importance in making foundry molds and cores, fiberglass composites, mortars, cements, plastic insulation foams, refractory mixes, high carbon composites, and aggregate binders, among others.