Furfural tetrahydrofurfuryl alcohol

The most important physical properties of furfural, as well as similar properties for furfuryl alcohol, tetrahydrofurfuryl alcohol and furan are given in Table 1. The tabulated properties of furfural are supplemented by a plot (Fig. 1) of the vapor—Hquid compositions for the system, furfural—water (15,16). 

Furfural Furfuryl alcohol Furan Tetrahydrofurfuryl alcohol... 

Uses. Furfural is primarily a chemical feedstock for a number of monomeric compounds and resins. One route produces furan by decarbonylation. Tetrahydrofuran is derived from furan by hydrogenation. Polytetramethylene ether glycol [25190-06-1] is manufactured from tetrahydrofuran by a ring opening polymeri2ation reaction. Another route (hydrogenation) produces furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-methylfuran, and 2-methyltetrahydrofuran. A variety of proprietary synthetic resins are manufactured from furfural and/or furfuryl alcohol. Other... 

As can be seen, most of the furfural produced in this country is consumed as an intermediate for other chemicals. Hydrogenation to furfuryl alcohol is the largest use. Some of the furfuryl alcohol is further hydrogenated to produce tetrahydrofurfuryl alcohol. The next major product is furan, produced by decarbonylation. Furan is a chemical intermediate, most of it is hydrogenated to tetrahydrofuran, which in turn is polymerized to produce polytetramethylene ether glycol (PTMEG). 

Other furan compounds, best derived from furfural, are of interest although commercial volumes are considerably less than those of furfural, furfuryl alcohol, furan, or tetrahydrofurfuryl alcohol. Some of these compounds are stiU in developmental stages. Apphcations include solvents, resin intermediates, synthetic mbber modifiers, therapeutic uses, as well as general chemical intermediates. 

Furfural. Furfural is readily obtainable from dehydration of pentoses. Reduction of furfural can lead to a variety of products that are more volatile, more stable and possibly also more useful than furfural itself. Selective reduction of the aldehyde moiety leads to furfuryl alcohol (Scheme 15), whereas further reduction of the furan core will lead to tetrahydrofurfuryl alcohol. Reductive deoxygenation can result in the formation of either 2-methylfuran or 2-methyltetrahydrofuran, which can be used as liquid fuels or solvents. 

The hydrogenation and hydrogenolysis pathways and products of furfural and furfuryl alcohol are summarized in Scheme 12.26. Hydrogenation of furfural over Adams platinum oxide in ethanol in the presence of ferrous chloride at room temperature and 1-2 atm H2 first led to quantitative formation of furfuryl alcohol, which was further hydrogenated to a mixture of 1-pentanol (11%), tetrahydrofurfuryl alcohol (35%),... 

Tetrahydrofurfuryl alcohol is made commercially from furfural by a high-pressme hydrogenation at 1000 to 1500 psi (67.889 to 101.833 ATM) and 170 to 180 °C, using a mixture of copper chromite and RANEY nickel as the catalyst [103] ... 

Polyheptanoamide via tetrahydrofurfuryl alcohol, which is derived from furfural (Nylon 7). 

Dihydro-2 -pyran is a colourless liquid, bp 86°C. It is obtained by catalytic dehydration of tetrahydrofurfuryl alcohol 14 14 in turn is obtained by hydrogenation of furfural (see p 60). 

Furan resins. Thermosets manufactured from furan derivatives such as furfural, furfuryl alcohol, tetrahydrofurfuryl alcohol. Applications foundry resins and core binders, acid-proof coatings, putties. 

Current world production of furfural is around 150,000 tpa the largest producer is Quaker Oats Chem. (USA). The main areas of application are the production of the solvents furfuryl alcohol and tetrahydrofurfuryl alcohol. Furfural itself is used as a solvent, especially for separating unsaturated and saturated compounds in petroleum refining. 

The aldehyde group stabilizes the furfural stmcture against the acid-catalyzed fission of the furan ring that readily occurs in furan and alkyl furan derivatives. Basic-type stabilizers, such as tertiary amines, can be used to inhibit oxidation of the furan structure [3]. Furfural can be oxidized to furoic acid or reduced to furfuryl alcohol which can be converted to furan by a catalyzed decarbonylation reaction. On an industrial scale furfural is the source for furfuryl alcohol, tetrahydrofurfuryl alcohol, furan, and tetrahydrofuran. Nitro-furan compounds derived from furfural are used as bactericides in humans. 

Interestingly, as shown in Scheme 8.103, if furfural (furan 2-carboxalehyde) is reduced with hydrogen (H2) in the presence of a Ni catalyst, the corresponding primary alcohol, tetrahydrofurfuryl alcohol, results. Then, if the that primary alcohol is heated to 350°C in the presence of an alumina (aluminum oxide, AI2O3) catalyst, rearrangement and dehydration occur to yield dihydropyran (oxahex-2-ene). 

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