Furfural, commercial production from

Furanose and pyranose, origin and definition of terms, III, 18 Furanose and pyranose rings, method of distinction in some cases, III, 103 Furfural, commercial production from pentosans, V, 288 from bagasse, IV, 296 from wood saccharification, IV, 178 —, 5-hydroxymethyl-, IV, 5, 307, 314, 336... 

Pentoses contained in hemicellulose are used to produce furfural, a useful industrial chemical, used as a solvent for resins and waxes and in petrochemical refining. It is also used as a feedstock for a range of aromatic substances (it has an almond odour) including preservatives, disinfectants and herbicides. Furfural can be converted to furfuryl alcohol and used to make resins for composite applications with fibreglass and other fibres. These are of interest in the aircraft component and automotive brake sectors. Furfural is commercially derived from acid hydrolysis of waste agricultural by-products, such as sugarcane bagasse, com cobs and cereal brans. Around 450 000 tonnes is produced by this method per year. 

Abstract The synthesis and chemistry of 5-(hydroxymethyl)furfural (HMF), 5-(chloromethyl)furfural (CMF), and levulinic acid (LA), three carbohydrate-derived platform molecules produced by the chemical-catalytic processing of lignocellulosic biomass, is reviewed. Starting from the historical derivation of these molecules and progressing through modem approaches to their production from biomass feedstocks, this review will then survey their principal derivative chemistries, with particular attention to aspects of commercial relevance, and discuss the relative merits of each molecule in the future of biorefining. 

Furan resin is a generic term for a thermoset resinous product that contains a heterocyclic unsaturated furan ring in its molecular structures. Pentosans from com cobs and rice hulls are the main sources for the key ingredient, furfural. Commercially, the furfural alcohol polymer is the most important. All furan resins are dark in color and have a reddish-black appearance when catalyzed to cure they become black. 

Uses. Furfuryl alcohol is widely used as a monomer in manufacturing furfuryl alcohol resins, and as a reactive solvent in a variety of synthetic resins and appHcations. Resins derived from furfuryl alcohol are the most important appHcation for furfuryl alcohol in both utihty and volume. The final cross-linked products display outstanding chemical, thermal, and mechanical properties. They are also heat-stable and remarkably resistant to acids, alkaUes, and solvents. Many commercial resins of various compositions and properties have been prepared by polymerization of furfuryl alcohol and other co-reactants such as furfural, formaldehyde, glyoxal, resorcinol, phenoHc compounds and urea. In 1992, domestic furfuryl alcohol consumption was estimated at 47 million pounds (38). 

Furfural is a colourless liquid which darkens in air and has a boiling point of 161.7°C at atmospheric pressure. Its principal uses are as a selective solvent used in such operations as the purification of wood resin and in the extraction of butadiene from other refinery gases. It is also used in the manufacture of phenol-furfural resins and as a raw material for the nylons. The material will resinify in the presence of acids but the product has little commercial value. 

Relatively pure xylan isolated from the holocellulose of aspen (Populus) wood is said to contain 85% of xylose residues.78 One of the characteristic properties of xylan is its ease of hydrolysis. Because it hydrolyzes much more readily than cellulose, mild acid treatment may be employed to bring about preferential hydrolysis of xylan from plant material. Xylose is ordinarily prepared in the laboratory by direct sulfuric acid hydrolysis of the native xylan in ground corn cobs.74 Hydrolysis in hydrochloric acid proceeds rapidly, but decomposition to furfural also occurs to some extent.76 A commercial method for the production of D-xylose from cottonseed hulls76 and straw77 and from corn cobs17 78 has been described. 

Levulinic acid and formic acid are end products of the acidic and thermal decomposition of lignocellulosic material, their multistep formation from the hexoses contained therein proceeding through hydroxymethylfurfural (HMF) as the key intermediate, while the hemicellulosic part, mostly xylans, produces furfural.A commercially viable fractionation technology for the specific... 

Furfural is obtained commercially by mealing pentosan-rich ugricullural residues (corncobs, oat hulls, cottonseed hulls, hagasse. rice hulls) with a dilute acid and removing the furfural by steam distillation. Major industrial uses of furfuraldehyde include (1) the production of t urnns and tetrahydrofurans where the compound is an intermediate (2) Ihc solvent refining of petroleum and rosin products (3) the solvent binding of bonded phenolic products and (4) the extractive distillation of butadiene from other C4 hydrocarbons. 

Levulinic Acid. 4-Oxopenlanoic acid laevulinic acid -acetyl propionic acid. CjHtO, mol wt 116.11. C 51.72%, H 6.94%, O 41.34%. CHjCOCHjCHjCOOH. Laboratory procedure from starch Or cane sugar by boiling with 1ICI. McKenzie, Org. Syn. coll. vol. 1, 335 (1941). Produced commercially from low grade cellulose. By-product of furfural manuf. Extensive review Leonard, Ind. Eng. Chem. 48, 1331 (1956). 

As discussed in detail in Chapter 1 [1], the chemical-catalytic approach to biomass valorization is poised to come to the fore of biorefinery operations due to its advantages over microbial and thermochemical processing of lignocellulosic feedstocks. Below, we consider three mainstream platform chemicals, collectively referred to as furanics, that are derived from the acid-catalyzed dehydration of carbohydrates. The first, 5-(hydroxymethyl)furfural, or HMF 1, is an icon of the biorefinery movement. With derivatives that branch out over multiple product manifolds, HMF is a recognized commercial opportunity for whoever can manage to produce it economically, and approaches towards the realization of this aim will be discussed. 

Furfural or 2-furancarboxyaldehyde (F) was first obtained in the early nineteenth century and became an industrial commodity about a century later, to reach an industrial production today of some 280 000 tons pa- year [9]. It can be readily and economically prepared from a vast array of agricultural and forestry wastes containing pentoses (see Chapter 13) in sufficient amounts to justify a commercial exploitation. Examples of these renewable resources are com cobs, oat and rice hulls, sugarcane bagasse, cotton seeds, olive husks and stones, as well... 

FA is a bio-based material, produced by hydrogenation of furfural on an industrial scale. Furfural has been prepared in commercial quantities for many decades from pentose-rich agricultural residues, including rice hulls, bagasse, oat huUs, and corn cobs. Furfural can also be derived from wood and wood products, which represent a second natural storehouse for furfural [62],... 

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