Formaldehyde furfural

Aldehydes. The aldehydes studied in this program include acetaldehyde, chloroacetaldehyde, formaldehyde, furfural, crotonalde-hyde, and acrolein. Because of the instability of the aldehydes, they are best collected by derivatizing during sample collection. 

Other 2-substituted furan derivatives, including 2-furfurylamine and 2-meth-ylfuroate, have been condensed with aldehydes or ketones to form difunctional difuryl alkane derivatives (61). Previously, the condensation of 2-methylfuran with aldehydes and ketones, including formaldehyde, furfural, acetone, and the... 

Though many aldehydes can be made to react with phenol, only formaldehyde, the lowest molecular weight and most reactive aldehyde, is of major commercial importance. Acetaldehyde and butyraldehyde are used only to a limited extent and often in combination with formaldehyde. Furfural is also used, forming phenolic resins that readily oxidize resulting in dark brown to black products. 

Acetaldehyde Acetophenone Adipic acid Aniline Anthranilic acid Benzoguanamine 3,3, 4,4 -Benzophenone tetracarboxylic dianhydride 1,2,4-Butanetriol n-Butyraldehyde Caprolactam Ceteareth-30 Citric acid Dicyclopentadiene Diethyl aniline Dimer acid N,N-Dimethylaniline Dodecenylsuccinic anhydride Epichlorohydrin Ethylene dichloride Formaldehyde Furfural Hexahydrophthalic anhydride Hexamethylene glycol ... 

Porous carbon gels prepared by polycondensation of hydroxylated benzene (phenol, catechol, resorcinol, hydroquinone or phloroglucinol,. ..) and aldehyde (formaldehyde, furfural,...) in a solvent followed by drying and pyrolysis have been extensively studied for the past fifteen years [51-66, 101], Various carbon materials whose texture depends on the nature of the precursors, the gelation conditions and the drying method can be obtained. The most common precursors are resorcinol (1,3-dihydroxybenzene) and formaldehyde (CHjO) and the polymer is usually synthesized using water as solvent and sodium carbonate (NUjCOj) as catalyst. 

As indicated previously, commercial phenolic resins are almost exclusively based on formaldehyde. Furfural is occasionally used to produce resins with good flow properties (See Section 19.3.)... 

If formaldehyde is replaced by furfural, the furfural - phenol polymer (U.S.A. Durite) results. The above polymers are largely used for moulding purposes. 

Furfural has been used as a component in many resin appHcations, most of them thermosetting. A comprehensive review of the patent Hterature describing these uses is beyond the scope of this review. A few, selected recent patents and journal articles have been referenced. Resins prepared from the condensation products of furfural with urea (47), formaldehyde (48), phenols (49,50), etc, modified by appropriate binders and fillers are described in the technical Hterature for earlier appHcations, see reference 1, which contains many references in an appendix. 

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). 

Resins. As mentioned above, both furfural and furfuryl alcohol are widely used in resin apphcations. Another resin former, 2,5-furandimethanol [1883-75-6] (BHME), is prepared from furfuryl alcohol by reaction with formaldehyde. It is usually not isolated because oligomerization occurs simultaneously with formation (competing reaction). Both the monomer and oligomers are very reactive owing to difuntionahty, and are used primarily as binders for foundry sand (72) and fiberglass insulation (147,148). 

Dehydrogenation processes in particular have been studied, with conversions in most cases well beyond thermodynamic equihbrium Ethane to ethylene, propane to propylene, water-gas shirt reaction CO -I- H9O CO9 + H9, ethylbenzene to styrene, cyclohexane to benzene, and others. Some hydrogenations and oxidations also show improvement in yields in the presence of catalytic membranes, although it is not obvious why the yields should be better since no separation is involved hydrogenation of nitrobenzene to aniline, of cyclopentadiene to cyclopentene, of furfural to furfuryl alcohol, and so on oxidation of ethylene to acetaldehyde, of methanol to formaldehyde, and so on. 

The phenolics are resinous materials produced by condensation of a phenol, or mixture of phenols, with an aldehyde. Phenol itself and the cresols are the most widely used phenols whilst formaldehyde and, to a much less extent, furfural are almost exclusively used as the aldehydes. 

Heating the sugar with strong acid yields furfural derivatives. Aldohexoses can eliminate water and formaldehyde under these conditions yielding furfural. This adehyde reacts with amines according to I to yield colored Schiff s bases. Ketohex-oses condense with diphenylamine in acid medium with simultaneous oxidation according to II to yield the condensation product shown. 

Heating the sugars with strong add yields furfural derivatives. Under these conditions aldohexoses can eliminate formaldehyde and water to yield furfural. This aldehyde reacts with amines to yield colored Schiff s bases. 

Zone 4 alkyd, fluorinated ethylene-propylene, melamine-formaldehyde, phenol-furfural, and polysulfone. 

Fonofos Formaldehyde Formetanate.HCI Formic acid Furfural... 

Although most phenolic resins are made using formaldehyde, but other aldehydes have also been used. The only one of commercial importance is furfural which produces a resin having a high tensile and impact strength. 

Uses Manufacture of vanillin, Michler s ketone, methyl violet, and other dyes solvent reagent for methyl alcohol, hydrogen peroxide, methyl furfural, nitrate, and formaldehyde chemical intermediate stabilizer reagent. 

Several aldehydes, namely furfural, 5-hydroxymethylfurfural, " isovaleraldehyde, benzal-dehyde, propionaldehyde, isobutyraldehyde, formaldehyde, and 2-methylbutyraledehyde, were shown to react with catechin and malvidin 3-glucoside in the same way as acetaldehyde or... 

MP 42, 333-42(1960) CA 55, 14421(1961) (Prepn from furfural formaldehyde with NaOH in 80% yield — Cannizzaro reaction)... 

Polarographic methods of analysis of the derivatives of formaldehyde and crotonaldehyde without chromatography were developed. Analysis by HPLC was later considered so as to achieve greater resolution between the individual aldehydes and potential interferences. Methods validated using HPLC analysis include acetaldehyde and furfural. Tests indicated that HPLC analysis may be applicable to the Girard-T derivatives of other aldehydes, such as formaldehyde, propionaldehyde, and benzaldehyde. 

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