Furfural is used to make other furan derivatives, such as furoic acid, via oxidation, and furan itself via palladium catalyzed vapor phase decarbonylation. Furfural is also a specialized chemical solvent.
What is furfural used for in chemistry?
Furfural is used for making inks, plastics, antacids, adhesives, nematicides, fungicides, fertilizers, and flavoring compounds [60]. Furfural can be used as a solvent or in the making of furfuryl alcohol, tetrahydrofuran (THF), and levulinic acid (LA). Furfuryl alcohol is prepared by hydrogenation of furfural.
What is the history of furfural?
History. Furfural was first isolated in 1821 (published in 1832) by the German chemist Johann Wolfgang Döbereiner, who produced a small sample as a byproduct of formic acid synthesis. At the time, formic acid was formed by the distillation of dead ants, and Döbereiner's ant bodies probably contained some plant matter.
What is the color of furfural?
Furfural appears as colorless or reddish-brown mobile liquids with a penetrating odor. Flash points 140°F. Denser than water and soluble in water. Vapors heavier than air. May be toxic by ingestion, skin absorption or inhalation. Furfural is an aldehyde that is furan with the hydrogen at position 2 substituted by a formyl group.
What is the solubility of furfural?
Furfural dissolves readily in most polar organic solvents, but it is only slightly soluble in either water or alkanes. Furfural participates in the same kinds of reactions as other aldehydes and other aromatic compounds.
What is furfural made from?
Furfural is one of the furan derivatives formed from the hemicellulosic portion of lignocellulosics. Furfural is a natural dehydration product of xylose, a pentose sugar often found in large quantities in the hemicellulose fraction of lignocellulosic biomass.
Where is furfural found?
Today, furfural is still produced from agricultural byproducts like sugarcane bagasse and corn cobs. The main countries producing furfural today are the Dominican Republic, South Africa and China.
Why is furfural toxic?
In humans, furfural is metabolized to furoic acid, a natural component of urine, with a high elimination rate in heavy drinkers of coffee. Like other aldehydes, furfural is irritant to the skin, eyes and respiratory tract. Seizures and cytolytic hepatitis have been described in early case reports.
What is furfuryl alcohol used for?
Furfuryl Alcohol is a colorless or yellow liquid that turns red or brown in air. It has a mild Alcohol or Ether-like odor and is used as a flavoring and in making sealants and cements.
What does furfural taste like?
Furfural (FEMA# 2489, CAS# 98-01-1) is the most significant flavor compound generated during the heating of sugars in nature. The profile of furfural is, unsurprisingly, quite brown and caramelic.
How do I get furfural?
Furfural is produced by removing water from or dehydrating five-carbon sugars such as xylose and arabinose. These pentose sugars are commonly obtained from the hemicellulose fraction of biomass wastes like cornstalks, corncobs and the husks of peanuts and oats.
Is furfural biodegradable?
CSTR systems in which furfural was continuously added resulted in 80% of the theoretically expected biogas. Intermediates in the anaerobic biodegradation of furfural were determined by spike additions in serum-bottle assays using the enriched consortium from the CSTR systems.
Does glucose give furfural test?
The rapid furfural test is a chemical test used to distinguish between glucose and fructose. The rapid furfural test is similar to Molisch's test but uses concentrated hydrochloric acid instead of concentrated sulfuric acid and the solution is boiled.
What is furfural reaction?
Due to the two chemical functionalities present — aldehyde group and aromatic ring — furfural can undergo typical aldehyde reactions, such as nucleophilic additions, condensation reactions, oxidations or reductions, as well as others associated to the furan ring such as electrophilic aromatic substitution or ...
Why is furfuryl alcohol in White Castle burgers?
Furfuryl alcohol is a naturally occurring byproduct of heating and appears in many foods and beverages. Furfuryl alcohol forms as a result of baking that gives our buns the characteristic brown color tops. It is not added to our products.
What foods are furfuryl alcohol in?
The highest content of furfuryl alcohol was found in coffee beans (>100 mg/kg) and in some fish products (about 10 mg/kg), while among beverages, wines contained between 1 and 10 mg/L, with 8 mg/L in pineapple juice. The content of β-myrcene was highest in hops.
Is furfuryl alcohol cancerous?
US EPA concluded that furfuryl alcohol is “Likely to be Carcinogenic to Humans”.
What is furfural biochemistry?
Furfural is an aldehyde that is furan with the hydrogen at position 2 substituted by a formyl group. It has a role as a Maillard reaction product and a metabolite. It is a member of furans and an aldehyde. It derives from a furan. ChEBI.
Is furfural a carbohydrate?
Introduction to Glycoscience; Synthesis of Carbohydrates Furfural (515, furfuraldehyde) is a very inexpensive starting material obtained from the left-overs of agriculture (acidic distillation of straw and brans).
Does glucose give furfural test?
The rapid furfural test is a chemical test used to distinguish between glucose and fructose. The rapid furfural test is similar to Molisch's test but uses concentrated hydrochloric acid instead of concentrated sulfuric acid and the solution is boiled.
Is furfural soluble in water?
Its ignition temperature is 315 °C, and solubility in water at 20 °C is 8.3 g per 100 ml of water. Furfural vapor is irritating to the mucous membranes, but the low volatility reduces the risk of exposure.
What is furfural oil?
George Fownes named this oil "furfurol" in 1845 (from furfur (bran), and oleum (oil)). In 1848, the French chemist Auguste Cahours determined that furfural was an aldehyde. Determining the structure of furfural required some time: the furfural molecule contains a cyclic ether ( furan ), which tends to break open when it's treated with harsh reagents. In 1870, German chemist Adolf von Baeyer speculated (correctly) about the structure of the chemically similar compounds furan and 2-furoic acid. By 1886, furfurol was being called "furfural" (short for "furfuraldehyde") and the correct chemical structure for furfural was being proposed. By 1887, the German chemist Willy Marckwald had inferred that some derivatives of furfural contained a furan nucleus. In 1901, the German chemist Carl Harries determined furan's structure by synthesizing it from succindialdehyde, thereby also confirming furfural's proposed structure.
How is furfural made?
In the laboratory, furfural can be synthesized from plant material by heating with sulfuric acid or other acids. With the purpose to avoid toxic effluents, an effort to substitute sulfuric acid with easily-separable and reusable solid acid catalysts has been studied around the world.
Where does the name Furfural come from?
The name furfural comes from the Latin word furfur, meaning bran, referring to its usual source. Furfural is only derived from lignocellulosic biomass, i.e., its origin is non-food or non-coal/oil based. Aside from ethanol, acetic acid and sugar it is one of the oldest renewable chemicals.
Which country produces furfural?
The global production capacity is about 800,000 tons as of 2012. China is the biggest supplier of furfural, and accounts for the greater part of global capacity. The other two major commercial producers are Illovo Sugar in the Republic of South Africa and Central Romana in the Dominican Republic.
Who discovered the structure of furfural?
By 1887, the German chemist Willy Marckwald had inferred that some derivatives of furfural contained a furan nucleus. In 1901, the German chemist Carl Harries determined furan's structure by synthesizing it from succindialdehyde, thereby also confirming furfural's proposed structure.
Is furfural mutagenic?
Furfural is carcinogenic in lab animals and mutagenic in single cell organisms, but there is no data on human subjects. It is classified in IARC Group 3 due to the lack of data on humans and too few tests on animals to satisfy Group 2A/2B criteria. It is hepatotoxic.
What is furfural used for?
Furfural is used as a selective solvent for refining lubricating oils and rosin, and to improve the characteristics of diesel fuel and catalytic cracker recycle stocks.
What is the chemical name for furfural?
Furfural (C4H3O-CHO), also called 2-furaldehyde, best known member of the furan family and the source of the other technically important furans. It is a colourless liquid (boiling point 161.7 °C; specific gravity 1.1598) subject to darkening on exposure to air.
How long did furfural dissolve?
It dissolves in water to the extent of 8.3 percent at 20 °C and is completely miscible with alcohol and ether. A span of about 100 years marked the period from discovery of furfural in the laboratory to the first commercial production in 1922.
When vapours of furfural and hydrogenare passed over a coppercatalystat elevated temperature, is?
When vapours of furfural and hydrogenare passed over a coppercatalystat elevated temperature, furfuryl alcoholis formed. This important derivative is used in the plasticsindustry for the production of corrosion-resistant cements and cast-molded items. The similar hydrogenationof furfuryl alcohol over a nickelcatalystgives tetrahydrofurfuryl alcohol, from which are derived various esters and dihydropyran.
Is furfural an aldehyde?
In its reactions as an aldehyde, furfural bears a strong resemblance to benzaldehyde. Thus, it undergoes the Cannizzaro reaction in strong aqueous alkali; it dimerizes to furoin, C 4 H 3 OCO-CHOH-C 4 H 3 O, under the influence of potassium cyanide; it is converted to hydrofuramide, (C 4 H 3 O-CH) 3 N 2, by the action of ammonia.
What are some applications of furfural?
The acceptance of furfural as a substitute for petrochemicals as a building block led to the emergence of novel applications, such as manufacturing tetrahydrofuran, furfuryl alcohol resins, and furanics; timber treatment; soil conditioning; and as biofuel.
What is furfural made of?
Furfural is one of the furan derivatives formed from the hemicellulosic portion of lignocellulosics. Furfural is a natural dehydration product of xylose, a pentose sugar often found in large quantities in the hemicellulose fraction of lignocellulosic biomass.
How is THF produced?
THF is produced by decarbonylation of furfural to furan followed by catalytic hydrogenation [61]. LA is produced in two reactions, with furfural converting to furfuryl alcohol being the first. Furfuryl alcohol, when boiled in ethyl methyl ketone in the presence of HCl, gives rise to levulinic acid with 90%–93% yield.
How is furfural formed?
Furfural is formed by dehydrating five-carbon sugars such as xylose and arabinose that can be obtained from the hemicellulose fraction of lignocellulosic biomass. More than one reaction mechanism has been proposed in different studies based on different techniques and under different reaction conditions. Firstly, the reaction was supposed to start from the acyclic form of the pentoses, either via a 1,2-enediol intermediate and subsequent dehydration ( Fig. 9.9) [56] or directly via a 2,3- (α,β-)unsaturated aldehyde, ( Fig. 9.10) [57]. Other groups believed that the reaction starting from the pyranose form of the pentoses, initially an intermediate compound 2,5-anhydroxylose furanose, was formed by the action of H + on the O − 2 of the pyranose ring, and it is subsequently dehydrated to furfural ( Fig. 9.11) [58].
How is HMF transformed?
HMF can be transformed by hydrogenolysis to 2,5-dimethyl furan. To form larger hydrocarbons, HMF and other furfural products can be upgraded by aldol condensation with ketones, such as acetone, over a basic catalyst (NaOH) already at room temperatures (West et al., 2008 ).
How does furfural biodegrade?
When released into the environment, it volatilizes readily. In the air, furfural is degraded by reaction with hydroxy radicals produced photolytically. If released into the soil, it is highly mobile and has a great potential to leach into groundwater. Volatilization from the soil is expected to be slow. Although data is limited, furfural is expected to biodegrade readily in the soil under both aerobic and anaerobic conditions. Furfural will not bioconcentrate to any great extent in fish or wildlife.
What is the global demand for furfural?
Global demand for furfural was 300 kilo tons in 2013 and is expected reach 652.5 kilo tons by 2020. The estimated compound annual growth rate (CAGR) is 13.3% from 2014 to 2020 for this chemical. China, the dominant player in furfural market, contributes 85% of global production capacity and 75% of world consumption.
What is furfural resin?
Furfural (2-furaldehyde) is a oily liquid with an aromatic odour, used as a solvent and raw material in the manufacture of phenol-formaldehyde-furfural resins, and in foundries for the preparation of molds for metal castings. In humans, furfural is metabolized to furoic acid, a natural component of urine, with a high elimination rate in heavy drinkers of coffee. Like other aldehydes, furfural is irritant to the skin, eyes and respiratory tract. Seizures and cytolytic hepatitis have been described in early case reports. Sensitization (dermatitis, rhinitis, asthma) can also occur in occupational settings, for example in foundry workers [32].
How does furfural biodegrade?
When released into the environment, it volatilizes readily. In the air, furfural is degraded by reaction with hydroxy radicals produced photolytically. If released into the soil, it is highly mobile and has a great potential to leach into groundwater. Volatilization from the soil is expected to be slow. Although data is limited, furfural is expected to biodegrade readily in the soil under both aerobic and anaerobic conditions. Furfural will not bioconcentrate to any great extent in fish or wildlife.
How is furfurylamine obtained?
The primary commercial sources of pentosans (polysaccharides that yield pentoses upon hydrolysis) are corncobs and sugar cane bagasse. However, other pentosan-containing materials (e.g., hardwood residues and rice hulls) could be used. Furfural is converted to furfurylamine by reductive amination. Furfurylamine can be used as the starting material for the synthesis of difurfur yl diisocyanates. The mechanical properties of flakeboards bonded with difurfuryl diisocyanate (e.g., EDFI) were comparable with the properties that were obtained with MDI ( Holfinger et al. 1993, Coppock et al. 1996 ). Thus, EDFI is an excellent adhesive that can be derived from renewable resources.
What is xylose used for?
Xylose is used as a media ingredient to produce xylose/glucose isomerase which is used in the production of high-fructose corn syrups.
Does furfural alkylate ring?
Furfural-derived 2-furylhydrazone underwent alkylated ring opening with phenyl Grignard reagents to produce dienal products, as shown in Equation (175). However, only reductive alkylation occurred with alkyl Grignard reagents (Equation 176) <2000TL2667>. Different elimination pathways of dinitrogen in the reaction intermediates, that is, [3,3]-sigmatropic rearrangement versus radical fragmentation, were probably responsible for the different products obtained.
Is furfural a lignocellulose inhibitor?
Furfural is one of the most important lignocellulose-derived inhibitors due to its abundance and strong cytotoxicity (Geddes, Nieves, & Ingram, 2011;
Where does furfural come from?
Furfural is found in several essential oils from plants of the pinaceae family, in the essential oil from cajenne linaloe, in the oil of leaves of trifolium pratense and trifolium incarnatum, in the distillation waters of several essential oils such as ambrette and angelica seeds, in ceylon cinnamon essential oil, in petitgrain oil, ylang-ylang, lavender, lemongrass, calamus, eucalyptus, neroli, sandalwood, tobacco leaves, and others (1). Furfural is also found in the smoke from wildfires (2).
How is furfural released?
Furfural's production and use as a solvent, a chemical feedstock for furan derivatives and synthetic resins, a wetting agent, and a flavoring ingredient may result in its release to the environment through various waste streams. Furfural may also be released to the environment in the smoke of wood burning stoves or fireplaces, from tobacco smoke, and from automobile tailpipe emissions. Furfural is found in the essential oil of a variety of plants and in the smoke of wildfires. If released to air, a vapor pressure of 2.21 mm Hg at 25 °C indicates furfural will exist solely as a vapor in the atmosphere. Vapor-phase furfural will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 5.5 hours. Furfural contains chromophores that absorb at wavelengths >290 nm and therefore may be susceptible to direct photolysis by sunlight. The gas-phase concentration of furfural, present as a component of the smoke obtained from burning oak in a wood stove, was found to decrease when irradiated in an experimental chamber equipped both with sun lights and UV lights. If released to soil, furfural is expected to have very high mobility based upon an estimated Koc of 40. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 3.8X10-6 atm-cu m/mole. Furfural may volatilize from dry soil surfaces based upon its vapor pressure. Furfural was shown to support the aerobic growth of organisms obtained from soil and grown on phenol and 97% degradation was observed from 0.25-32 days at different furfural concentrations in a forest soil and municipal sewage mixture under anaerobic conditions. If released into water, furfural is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Furfural is expected to undergo biodegradation under aerobic and anaerobic conditions in the aquatic environment with complete degradation occuring within 3-12 days and 30 days, respectively. Also, furfural, present at 100 mg/L, reached 93.5% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 30 mg/L and the Japanese MITI test. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 9.6 and 73 days, respectively. An estimated BCF of 3.2 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. An initial furfural concentration of 1.5 ppm in distilled water was found to decrease by only 0.1 ppm after 30 days at 20 °C, suggesting that hydrolysis under neutral conditions is not an important fate process. Even at high temperatures, long exposure times are necessary for extensive hydrolysis of furfural by dilute acids. Occupational exposure to furfural may occur through inhalation and dermal contact with this compound at workplaces where furfural is produced or used. Monitoring data indicate that the general population may be exposed to furfural via inhalation of ambient air, ingestion of food and drinking water, and dermal contact with this compound and other products containing furfural. Furfural is widely detected in food, indoor air, and smoke from wood fires. (SRC)
How is furfural metabolized?
Furfural is metabolized primarily by oxidation of the aldehyde function in rats and mice. Oxidation yields furoic acid, which, as the coenzyme A ( CoA) thioester, is either conjugated with glycine and excreted or condensed with acetyl CoA to form the chain-lengthened metabolite 2-furanacryloyl CoA. 2-furanacryloyl CoA conjugates with glycine and and is excreted primarily in the urine. In rats and mice, furoic acid appears to decarboxylate to a very minor extent (approximately 1%) via oxidation of the furan ring to yield carbon dioxide ... .
How long does furfural stay in the body?
It is metabolized very rapidly. Half-life is about 2 to 2.5 hours. No free furoic acid found. This compound enters the body also percutaneously. At 15 minutes contamination of 1 hand (up to the wrist), approximately the same amount of furfural is absorbed as would be retained at an 8 hour (or 4 hour) inspiration of air in concentration equaling maximum allowable concentration.
What is the BCF of furfural?
An estimated BCF of 3.2 was calculated for furfural (SRC), using a log Kow of 0.41 (1) and a regression-derived equation (2). According to a classification scheme (3), this BCF suggests the potential for bioconcentration in aquatic organisms is low (SRC).
How long does it take for furfural to degrade?
The rate of degradation at a higher initial furfural concentration was found to be dependent upon the degree of acclimation, and fully acclimated seeds were round to degrade 25 ppm furfural within 5-12 days (2). At initial concentrations of 1.7-20 and 440 ppm, furfural underwent 46% and 17% theoretical BOD, respectively, in 5 days using a sewage sludge seed under aerobic conditions (3). Furfural at an initial concentration of 300 mg/L, in solution with phenol and N-methyl-2-pyrolidine, was found to undergo 98% removal in a flow-through laboratory bioreactor using an activated sludge inoculum under aerobic conditions (4). At an initial feed concentration of 1,000 mg/L, degradation was also found to occur (4). Furfural at an initial concentration of 200 mg/L COD underwent 96.3% removal in less than 120 hours using a thickened adapted activated sludge under aerobic conditions (5). Furfural was shown to support the aerobic growth of organisms obtained from soil and grown on phenol (6).
What was the furfural level of wildland fires in California?
California wildland firefighters were exposed to a mean furfural level of 0.13 mg/cu m (25 samples) present in the smoke of wildland fires and prescribed burns in mountainous areas with heavy timber in northern California during the fire season of 1989 (2).
Overview
History
Properties
- Now that we know what the structure of furfural looks like and how it's produced, let's talk about a couple of the more important applications it can be utilized for. If we take furfural and convert the aldehyde to an alcohol in what's called a reduction reaction, we get furfuryl alcohol (abbreviated FA). FA is used in the manufacture of things lik...
Production
Furfural is an organic compound with the formula C4H3OCHO. It is a colorless liquid, although commercial samples are often brown. It has an aldehyde group attached to the 2-position of furan. It is a product of the dehydration of sugars, as occurs in a variety of agricultural byproducts, including corncobs, oat, wheat bran, and sawdust. The name furfural comes from the Latin word furfur, meaning bran, referring to its usual source. Furfural is only derived from lignocellulosic bio…
Uses and occurrence
Furfural was first isolated in 1821 (published in 1832) by the German chemist Johann Wolfgang Döbereiner, who produced a small sample as a byproduct of formic acid synthesis. In 1840, the Scottish chemist John Stenhouse found that the same chemical could be produced by distilling a wide variety of crop materials, including corn, oats, bran, and sawdust, with aqueous sulfuric acid; he also determined furfural's empirical formula (C5H4O2). George Fownes named this oil "furfurol…
Safety
Furfural dissolves readily in most polar organic solvents, but it is only slightly soluble in either water or alkanes.
Furfural participates in the same kinds of reactions as other aldehydes and other aromatic compounds. It exhibits less aromatic character than benzene, as can be seen from the fact that furfural is readily hydrogenated to tetrahydrofurfuryl alcohol. When heated in the presence of acid…
See also
Furfural may be obtained by the acid catalyzed dehydration of 5-carbon sugars (pentoses), particularly xylose.
C 5H 10O 5 → C 5H 4O 2 + 3 H 2O
These sugars may be obtained from pentosans obtained from hemicellulose present in lignocellulosic biomass.
External links
It is found in many foods: coffee (55–255 mg/kg) and whole grain bread (26 mg/kg).
Furfural is an important renewable, non-petroleum based, chemical feedstock. It can be converted into a variety of solvents, polymers, fuels and other useful chemicals by a range of catalytic reduction.
Hydrogenation of furfural provides furfuryl alcohol (FA), which is used to produce Furan resins, whi…