98-01-1

Hazards Identification

Pictogram(s):

Signal:

Danger

GHS Hazard Statements:

H301: Toxic if swallowed [Danger Acute toxicity, oral]
H312: Harmful in contact with skin [Warning Acute toxicity, dermal]
H315: Causes skin irritation [Warning Skin corrosion/irritation]
H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]
H331: Toxic if inhaled [Danger Acute toxicity, inhalation]
H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]
H351: Suspected of causing cancer [Warning Carcinogenicity]

Precautionary Statement Codes:

P203, P261, P264, P264+P265, P270, P271, P280, P301+P316, P302+P352, P304+P340, P305+P351+P338, P316, P317, P318, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501

Hazard Classes and Categories:

Carc. 2
Acute Tox. 3 *
Acute Tox. 4 *
STOT SE 3
Skin Irrit. 2
Eye Irrit. 2
Acute Tox. 3 (100%)
Acute Tox. 4 (99.95%)
Skin Irrit. 2 (95.35%)
Eye Irrit. 2 (100%)
Acute Tox. 2 (11.51%)
Acute Tox. 3 (88.54%)
STOT SE 3 (100%)
Carc. 2 (100%)
Acute toxicity - category 3
Carcinogenicity - category 2
Skin irritation - category 2
Specific target organ toxicity (single exposure) - category 3
Eye irritation - category 2A
Flammable liquids - Category 3
Acute toxicity (Oral) - Category 3
Acute toxicity (Dermal) - Category 3
Acute toxicity (Inhalation: Vapours) - Category 2
Skin corrosion/irritation - Category 2
Serious eye damage/eye irritation - Category 2A
Carcinogenicity - Category 2
Specific target organ toxicity - Single exposure - Category 1 (respiratory organs, liver)
Specific target organ toxicity - Repeated exposure - Category 1 (respiratory organs, liver)
Hazardous to the aquatic environment (Acute) - Category 3
Specific target organ toxicity - Single exposure - Category 1 (respiratory system, liver)
Specific target organ toxicity - Repeated exposure - Category 1 (respiratory system), Category 2 (liver)
Hazardous to the aquatic environment (Long-term) - Category 3
Flammable - 2nd degree, Reactive - 1st degree

Hazards Summary:

Liquid causes first degree burns on short exposure. [CHRIS] At concentrations of 1.9 to 14 ppm, vapor can cause weeping of the eyes. [HSDB] TLV Basis is upper respiratory tract irritation and eye irritation; Hepatotoxicity reported in rats exposed to higher oral doses (30-60 mg/kg); [ACGIH] An irritant that defats the skin and may injure the liver; [ICSC] Vapor is eye and respiratory tract irritant; [CAMEO] Furfuraldehydes (UN1199) has warning of explosive polymerization; [ERG 2016]

Usage

Uses

Used in Chemical Production:
Furfural is used as an intermediate for the synthesis of furan derivatives, tetrahydrofuran, furfural alcohol, phenolic, and furan polymers.
Used in Petroleum Refining:
Furfural is used as a selective solvent in the solvent refining of lubricating oils and as a solvent in petroleum refining.
Used in Agriculture:
Furfural is used as an insecticide, fungicide, and germicide for controlling unwanted microorganisms, fungi, weeds, insects, and nematodes. Application methods include drip irrigation, spray boom, sprinkler, and low-pressure backpack spray.
Used in Manufacturing Industries:
Furfural is used as a solvent in various manufacturing industries, such as the production of phenolic resins, rubber vulcanization accelerant, and synthetic resins.
Used in Consumer and Personal Care Products:
Furfural is used as a wetting agent, flavoring ingredient in foods like roasted coffee, and fragrance in consumer and personal care products like fragrance cream, bath products, and toiletries.
Used in Analytical Chemistry:
Furfural is used as a reagent in analytical chemistry.
Used in Plastics Manufacturing:
Furfural is used in the manufacture of furfural-phenol plastics such as Durite.
Used in the Preparation of Pyromucic Acid:
Furfural is used in the preparation of pyromucic acid.
Used in the Manufacture of Varnishes:
Furfural is used as a solvent for nitrated cotton, cellulose acetate, and gums in the manufacture of varnishes.
Used in Vulcanization Acceleration:
Furfural is used for accelerating vulcanization in the rubber industry.

References

https://en.wikipedia.org/wiki/Furfural https://www.britannica.com/science/furfural https://pubchem.ncbi.nlm.nih.gov/compound/2-Furaldehyde#section=Top http://www.wisegeek.com/what-is-furfural.htm

Production Methods

Furfural is obtained commercially by treating pentosan-rich agricultural residues (corncobs, oat hulls, cottonseed hulls, bagasse, rice hulls) with a dilute acid and removing the furfural by steam distillation. Major industrial uses of furfuraldehyde include: (1) the production of furans and tetrahydrofurans where the compound is an intermediate; (2) the 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. When pentoses, e.g., arabinose, xylose, are heated with dilute HCl, furfuraldehyde is formed, recognizable by deep red coloration with phloroglucinol, or by the formation, with phenylhydrazine, of furfuraldehyde phenylhydrazone C4H3O·CH : NNHC6H5, solid, mp 97 °C.

Preparation

Industrially prepared from pentosans that are contained in cereal straws and brans; these materials are previously digested with diluted H2SO4, and the formed furfural steam is distilled.

Reactions

Aside from a darkening in color, furfural is relatively stable thermally and does not exhibit changes in physical properties after prolonged heating up to 230°C. The reactions of furfural are typical of those of the aromatic aldehydes, although some complex side reactions occur because of the reactive ring. Furfural yields acetals, condenses with active methylene compounds, reacts with Grignard reagents, and provides a bisulfite complex. Upon reduction, furfural yields furfural alcohol; upon oxidation, it yields furoic acid. It can be decarbonylated to furan.

Synthesis Reference(s)

The Journal of Organic Chemistry, 45, p. 3449, 1980 DOI: 10.1021/jo01305a015

Air & Water Reactions

Flammable. Furfural is sensitive to light and air. Soluble in water, with mixing.

Reactivity Profile

Furfural reacts with sodium hydrogen carbonate. Furfural also can react with strong oxidizers. An exothermic resinification of almost explosive violence can occur upon contact with strong mineral acids or alkalis. Furfural forms condensation products with many types of compounds, including phenol, amines and urea. .

Hazard

Absorbed by skin; irritant to eyes, skin, and mucous membranes. Toxic by skin absorption; questionable carcinogen.

Health Hazard

Vapor may irritate eyes and respiratory system. Liquid irritates skin and may cause dermatitis.

Flammability and Explosibility

Nonflammable

Safety Profile

Confirmed carcinogen. Poison by ingestion, intraperitoneal, subcutaneous, intravenous, and intramuscular routes. Moderately toxic by inhalation and sktn contact. Human mutation data reported. A skin and eye irritant. Mutation data reported. The liquid is dangerous to the eyes. The vapor is irritating to mucous membranes and is a central nervous system poison. However, its low volatility reduces its toxicity effect. Ingestion of furfural has produced cirrhosis of the liver in rats. In industry there is a tendency to minimize the danger of acute effects resulting from exposure to it. This is particularly true because of its low volathty. Flammable liquid when exposed to heat or flame; can react with oxidizing materials. Moderate explosion hazard when exposed to heat or flame or by chemical reaction. An exothermic polymerization of almost explosive violence can occur upon contact with strong mineral acids or alkalies. Keep away from heat and open flames. Mixture with sodium hydrogen carbonate ignites spontaneously. To fight fire, use alcohol foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes.

Potential Exposure

Furfural is used for lube oil refining and butadiene extraction; as a solvent for wood resin, nitrated cotton, cellulose acetate, and gums; in the produc tion of phenolic plastics, thermosetting resins, refined petroleum oils, dyes, and varnishes; in the manufacture of pyromucic acid, vulcanized rubber, insecticides, fungicides, herbicides, germicides, furan derivatives, polymers, and other organic chemicals.

Carcinogenicity

The IARC evaluated furfural and determined that there was inadequate evidence in humans for the carcinogenicity of furfural. There is limited evidence in experimental animals for the carcinogenicity of furfural.

Source

Furfural occurs naturally in many plants including rice (90,000–100,000 ppm), lovage roots (2 to 20 ppm), caraway, strawberry leaves, cilantro, java cintronella, cassia, ylang-ylang, sweetflag, Japanese mint, oat husks (100,000 ppm), anise, broad-leaved lavender, myrtle flowers (0–1 ppm), lemon verbena, Karaya gum (123,000 ppm), nutmeg seeds (15,000 ppm), West Indian lemongrass, licorice roots (2 ppm), cinnamon bark (3 to 12 ppm), Hyssop shoots (1–2 ppm), periwinkle leaves, rockrose leaves, and garden dill (Duke, 1992). Identified as one of 140 volatile constituents in used soybean oils collected from a processing plant that fried various beef, chicken, and veal products (Takeoka et al., 1996). The gas-phase tailpipe emission rate from California Phase II reformulated gasoline-powered automobile without a catalytic converter was 1.70 mg/km (Schauer et al., 2002).

Environmental fate

Biological. Under nitrate-reducing and methanogenic conditions, furfural biodegraded to methane and carbon dioxide (Knight et al., 1990). In activated sludge inoculum, following a 20-d adaptation period, 96.3% COD removal was achieved. The average rate of biodegradation was 37.0 mg COD/g?h (Pitter, 1976). Photolytic. Atkinson (1985) reported an estimated photooxidation half-life of 10.5 h for the reaction of furfural with OH radicals in the atmosphere. Chemical/Physical. Slowly resinifies at room temperature (Windholz et al., 1983). May polymerize on contact with strong acids or strong alkalies (NIOSH, 1997).

Shipping

UN1199 Furaldehyde, Hazard class: 6.1; Labels: 6.1-Poisonous materials, 3-Flammable liquid.

Purification Methods

Furfural is unstable to air, light and acids. Impurities include formic acid, .-formylacrylic acid and furan-2-carboxylic acid. Distil it in an oil bath from 7% (w/w) Na2CO3 (added to neutralise acids, especially pyromucic acid). Redistil it from 2% (w/w) Na2CO3, and then, finally fractionally distil it under vacuum. It is stored in the dark. [Evans & Aylesworth Ind Eng Chem (Anal ed) 18 24 1926.] Impurities resulting from storage can be removed by passage through chromatographic grade alumina. Furfural can be separated from impurities other than carbonyl compounds by the bisulfite addition compound. The aldehyde is steam volatile. It has been purified by distillation (using a Claisen head) under reduced pressure. This is essential as is the use of an oil bath with temperatures of no higher than 130o which is highly recommended. When furfural is distilled at atmospheric pressure (in a stream of N2), or under reduced pressure with a free flame (caution: because the aldehyde is flammable), an almost colourless oil is obtained. After a few days and sometimes a few hours, the oil gradually darkens and finally becomes black. This change is accelerated by light and occurs more slowly when it is kept in a brown bottle. However, when the aldehyde is distilled under vacuum and the bath temperature kept below 130o during the distillation, the oil develops only a slight colour when exposed to direct sunlight during several days. The distillation of very impure material should NOT be attempted at atmospheric pressure; otherwise the product darkens very rapidly. After one distillation under vacuum, a distillation at atmospheric pressure can be carried out without too much decomposition and darkening. The liquid irritates mucous membranes. Store it in dark containers under N2, preferably in sealed ampoules. [Adams & Voorhees Org Synth Coll Vol I 280 1941, Beilstein 17/9 V 292.]

Toxicity evaluation

The limited data in animals are insufficient for deriving a plausible mechanism of toxicity. Nevertheless, aldehyde functional group is intrinsically reactive and low molecular weight aldehydes such as formaldehyde are known to interact with biologically important macromolecules such as DNA, structural proteins, and enzymes. This supposition is consistent with the toxic effects observed at multiple sites, i.e., respiratory system, nervous system, liver, and kidneys.

Incompatibilities

May form explosive mixture with air. Acids and bases can cause polymerization, causing fire or explosion hazard. Reacts violently with oxidants. Incompatible with strong acids; caustics, ammonia, ali phatic amines; alkanolamines, alromatic amines; oxidizers. Attacks many plastics.

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinera tor equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transpor tation, treatment, and waste disposal.

InChI:InChI=1/C5H4O2/c6-4-5-2-1-3-7-5/h1-4H

Synthetic route

(2-furyl)methyl alcohol (98-00-0) → furfural (98-01-1)

Conditions	Yield
With bis(2,2'-bipyridyl) copper(II) permanganate In acetone for 0.1h; Ambient temperature;	100%
With 4 A molecular sieve; tetrabutylammonium perchlorate; Ru-Cu-Al-hydrotalcite In toluene at 60℃; for 3h;	100%
With potassium carbonate In toluene at 70℃; for 2.5h; Reagent/catalyst;	100%

5-bromo-2-furancarboxaldehyde (1899-24-7) → furfural (98-01-1)

Conditions	Yield
In diethyl ether for 1h; Product distribution; Irradiation; photochemical debromination was investigated;	100%

Sodium; 6-{[1-furan-2-yl-meth-(E)-ylidene]-amino}-hexanoate → furfural (98-01-1)

Conditions	Yield
With hydrogenchloride for 0.0416667h; Product distribution; Ambient temperature; pH = 4-6, regeneration of aldehyde;	100%

(furan-2-yl)methylene diacetate (613-75-2) → furfural (98-01-1)

Conditions	Yield
With sulphated zirconia In acetonitrile at 60℃; for 2h; Microwave irradiation;	100%
With Montmorillonite K10 In dichloromethane for 0.333333h; Heating;	98%
With water; Sulfate; titanium(IV) oxide In dichloromethane for 0.0833333h; Deacetylation; Heating;	97%

2-(1,3-dithian-2-yl)furan (67421-75-4) → furfural (98-01-1)

Conditions	Yield
With dihydrogen peroxide; iodine; sodium dodecyl-sulfate In water at 20℃; for 1h; Micellar solution;	100%
With indium(III) trifluoride; water In acetonitrile for 3.5h; Reflux; chemoselective reaction;	93%
With 2,4,4,6-Tetrabromo-2,5-cyclohexadien-1-one; dihydrogen peroxide In water; acetonitrile at 20℃; for 0.75h;	90%
With eosin y In water; acetonitrile at 20℃; for 4h; Irradiation;	82%
With ammonium iodide; dihydrogen peroxide; sodium dodecyl-sulfate In water at 20℃; for 0.333333h; micellar medium;

furfural tosylhydrazone (18708-18-4) → furfural (98-01-1)

Conditions	Yield
With Cr-MCM-41 zeolite on silica gel for 0.1h; microwave irradiation;	98%
With benzeneseleninic anhydride In tetrahydrofuran at 40 - 50℃; for 2h;	88%
With 2,3-dicyano-5,6-dichloro-p-benzoquinone In dichloromethane; water at 20℃; for 2h; Oxidation; oxidative cleavage;	80%

D-xylose (58-86-6) → furfural (98-01-1)

Conditions	Yield
With sulfonated graphitic carbon nitride In water at 100℃; for 0.5h; Solvent; Temperature;	96%
With Sulfonated graphene at 150℃; for 0.666667h; Temperature; Sealed tube;	96%
With hydrogenchloride; 5-methyl-dihydro-furan-2-one In water at 224.84℃; under 28443.9 Torr; for 0.0375h; Kinetics; Temperature; Reagent/catalyst; Concentration; Flow reactor;	93%

2-(furan-2-yl)-1,3-dioxolane (1708-41-4) → furfural (98-01-1)

Conditions	Yield
With Montmorillonite K 10; water In acetone for 0.5h; Heating;	96%
With aluminum oxide; Oxone for 0.03h; Hydrolysis; Microwave irradiation;	93%
With iron(III) chloride hexahydrate; acetaldehyde In dichloromethane at 20℃; for 0.25h;	90%

2-furaldehyde oxime (1121-47-7) → furfural (98-01-1)

Conditions	Yield
With water; Dess-Martin periodane In dichloromethane at 5℃; for 0.333333h;	95%
With silica gel; iron(III) chloride for 0.0133333h; microwave irradiation;	92%
With bis(pyridine)silver(I) permanganate In dichloromethane for 0.0833333h; Ambient temperature;	90%

2-(Iodomethyl)tetrahydrofuran (117680-17-8) → furfural (98-01-1)

Conditions	Yield
With oxygen; kieselguhr; copper(l) chloride In hexane for 2h; Oxidation; Heating;	93%

2-(furan-2-ylmethylene)hydrazine-1-carboxamide → furfural (98-01-1)

Conditions	Yield
With aluminium trichloride; 1-benzyl-4-aza-1-azoniabicyclo[2.2.2]octane dichromate at 20℃; for 0.0125h;	93%
With sodium perborate In acetic acid at 40℃; for 1h; Oxidation;

2-(1,3-dithiolan-2-yl)furan (6008-83-9) → furfural (98-01-1)

Conditions	Yield
Stage #1: 2-(1,3-dithiolan-2-yl)furan In ethanol at 20℃; Stage #2: With water In ethanol at 20℃;	93%
With indium(III) trifluoride; water In acetonitrile for 3.5h; Reflux; chemoselective reaction;	89%
With indium (III) iodide; dihydrogen peroxide In water; toluene at 20℃; for 15h; Inert atmosphere; Sealed tube;

2-(furan-2-yl)-1,3-oxathiolane (81932-19-6) → furfural (98-01-1)

Conditions	Yield
Stage #1: 2-(furan-2-yl)-1,3-oxathiolane In ethanol at 20℃; Stage #2: With water In ethanol at 20℃;	93%
With copper(II) nitrate monohydrate at 90℃; for 0.333333h;	85%

furan-2-yl-acetic acid (2745-26-8) → furfural (98-01-1)

Conditions	Yield
With potassium carbonate In chloroform at 20℃; for 24h; Irradiation; Inert atmosphere;	93%

3-bromofurfural (14757-78-9) → furfural (98-01-1)

Conditions	Yield
In diethyl ether for 1h; Product distribution; Irradiation; photochemical debromination was investigated;	92%

D-Arabinose (10323-20-3) → furfural (98-01-1)

Conditions	Yield
With Dowex 50Wx8-100 ion-exchange resin at 100℃; for 6h; Ionic liquid; Sealed tube;	92%
With silicoaluminophosphate-44 In water; toluene at 170℃; for 8h;	63%
With 1-butyl-3-methylimidazolium tetrachloridoferrate(III) In water; butanone at 160℃; for 3h;	50.7%

2-methylfuran (534-22-5) → furfural (98-01-1)

Conditions	Yield
With nickel-doped graphene carbon nitride nanoparticles; air In ethanol at 25℃; for 8h; Irradiation; Green chemistry;	92%
With oxygen In acetonitrile at 20℃; for 18h; Irradiation;	95 %Spectr.
With tert.-butylhydroperoxide; C29H25Cl2N4Ru(1+)*F6P(1-) In acetonitrile at 60℃; for 3h; Schlenk technique; Inert atmosphere;	71 %Chromat.

L-lyxose (1949-78-6) → furfural (98-01-1)

Conditions	Yield
With 1-methyl-3-(4-sulfobutyl)-1H-imidazol-3-ium hydrogensulfate; 4-methyl-2-pentanone In water at 150℃; under 760.051 Torr; for 0.416667h; Autoclave;	91.4%

5-methyl-dihydro-furan-2-one (108-29-2) → furfural (98-01-1)

Conditions	Yield
With D-Xylose In water at 180℃; for 0.666667h; Temperature; Reagent/catalyst;	91.4%

β-D-xylopyranoside (2460-44-8) → furfural (98-01-1)

Conditions	Yield
With phosphorus and fluorine co-doped amorphous carbon nitride In tetrahydrofuran; water at 130℃; for 5h;	91%
With hydrogen In water at 150℃; under 750.075 Torr; Temperature;	87.6%
With vanadyl pyrophosphate In water; toluene at 170℃; for 6h;	56%

3-(2-furyl)acrylic acid (539-47-9) → furfural (98-01-1)

Conditions	Yield
With aluminum oxide; potassium permanganate In dichloromethane at 20℃;	90%

tert-butyldimethyl(2,2,2-trichloro-1-furan-2-ylethoxy)silane (1027382-27-9) → furfural (98-01-1)

Conditions	Yield
With tetrabutyl ammonium fluoride In tetrahydrofuran; N,N-dimethyl-formamide at 50℃;	90%

2-(ethoxymethyl)furan (6270-56-0) → furfural (98-01-1)

Conditions	Yield
With water; 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate In acetonitrile at 20℃; for 8h;	90%

2-(bis(phenylthio)methyl)furan (71778-41-1) → furfural (98-01-1)

Conditions	Yield
With indium(III) trifluoride; water In acetonitrile for 3h; Reflux; chemoselective reaction;	90%

D-ribose (50-69-1) → furfural (98-01-1)

Conditions	Yield
With Dowex 50Wx8-200 ion-exchange resin at 100℃; for 3h; Ionic liquid; Sealed tube;	90%
With 3-butyl-1-methyl-1H-imidazol-3-ium hexafluorophosphate; copper dichloride at 120℃; for 0.3h; Reagent/catalyst; Ionic liquid;	67 %Chromat.

2-(furan-2-yl)-5,5-dimethyl-1,3-dioxane (709-10-4) → furfural (98-01-1)

Conditions	Yield
With indium(III) trifluoride; water In acetonitrile for 2.5h; Reflux; chemoselective reaction;	89%

2-furancarbonyl chloride (527-69-5) → furfural (98-01-1)

Conditions	Yield
With pentacoordinated hydrogenosilane 1	87%
With bis(triphenylphosphine)copper(I) tetrahydroborate; triphenylphosphine In acetone at 25℃; for 1h;	78%
With tert-butyl isocyanide; CpRu(PiPr3)(CH3CN)2PF6; Dimethylphenylsilane In [(2)H6]acetone at 20℃; for 24h; chemoselective reaction;	100 %Spectr.
With tert-butyl isocyanide; CpRu(PiPr3)(CH3CN)2PF6; Dimethylphenylsilane In [(2)H6]acetone at 20℃; for 24h; chemoselective reaction;	Ca. 100 %Spectr.

2-furaldehyde dimethyl acetal (1453-62-9) → furfural (98-01-1)

Conditions	Yield
With indium(III) trifluoride; water In acetonitrile for 2h; Reflux; chemoselective reaction;	87%
indium(III) chloride In methanol; water for 2h; Heating;	85%

furan-2-ylmethanamine (617-89-0) → furfural (98-01-1)

Conditions	Yield
With 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical; [bis(acetoxy)iodo]benzene In dichloromethane at 0 - 20℃; for 0.333333h; Inert atmosphere; Green chemistry;	87%
With pyridoxal 5'-phosphate; sodium pyruvate In aq. phosphate buffer at 30℃; pH=7.5; Reagent/catalyst; Enzymatic reaction;

furan-2-carbaldehyde oxime (620-03-1) → furfural (98-01-1)

Conditions	Yield
With manganese triacetate In benzene for 1h; Heating;	86%
With antimonypentachloride In dichloromethane at 20℃; for 2.3h;	75%

furfural (98-01-1) + cyclohexanone (108-94-1) → (2E,6E)-2,6-bis(2-furylmethylene)cyclohexanone (62085-75-0)

Conditions	Yield
With sodium hydroxide In ethanol for 0.025h; microwave irradiation;	100%
With sodium hydroxide In ethanol; water at 20℃; for 24h; Inert atmosphere; Green chemistry;	99%
aluminum oxide for 0.0416667h; microwave irradiation;	98%

furfural (98-01-1) + p-toluidine (106-49-0) → furfurylidene-p-toluidine (13060-72-5)

Conditions	Yield
In methanol at 20℃; for 24h;	100%
In methanol at 20℃; for 24h;	100%
In methanol at 20℃;	85%

furfural (98-01-1) + 4-methoxy-aniline (104-94-9) → N-furfurylidene-p-anisidine (1749-14-0, 100239-11-0)

Conditions	Yield
With sodium sulfate In benzene for 0.5h; Ambient temperature;	100%
In methanol at 20℃; for 24h;	100%
In methanol at 20℃; for 24h;	100%

furfural (98-01-1) + aniline (62-53-3) → N-(2-furylmethylene)aniline (3237-23-8)

Conditions	Yield
With copper(II) bis(trifluoromethanesulfonate) In water at 20℃; for 0.0166667h;	100%
With aluminum oxide for 5h; Milling;	100%
sodium hydrogen sulfate; silica gel at 56 - 58℃; for 0.0244444h; microwave irradiation;	98%

furfural (98-01-1) + phosphonic acid diethyl ester (762-04-9) → diethyl (hydroxy(furan-2-yl)methyl)phosphonate (20627-09-2)

Conditions	Yield
With triethylamine In neat (no solvent) at 20℃; Pudovik Reaction; Inert atmosphere;	100%
With triethylamine at 50℃; Pudovik Reaction; Inert atmosphere; Sealed tube;	100%
With 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine supported on polystyrene In neat (no solvent) at 30℃; for 3h; Pudovik Reaction; Green chemistry;	99%

furfural (98-01-1) + ethyl 2-cyanoacetate (105-56-6) → ethyl (E)-2-cyano-3-(2-furyl)-2-propenoate (67449-75-6, 23973-22-0)

Conditions	Yield
With L-proline for 0.0333333h; Knoevenagel condensation; microwave irradiation;	100%
ytterbium(III) perfluorooctanesulfonate In toluene at 80℃; for 3h; Knoevenagel condensation;	99%
With polyacrylonitrile fiber modified with triethylenetetramine In water at 50℃; for 1.5h; Knoevenagel condensation;	99%

furfural (98-01-1) + naphthalen-2-ylamine (91-59-8) → (E)-1-(furan-2-yl)-N-(naphthalen-2-yl)methanimine (6233-18-7)

Conditions	Yield
In diethyl ether at 20℃; Inert atmosphere; Molecular sieve; Darkness;	100%

furfural (98-01-1) + acetylacetone (123-54-6) → 3-(furan-2-ylmethylene)pentane-2,4-dione (4728-04-5)

Conditions	Yield
With piperidine; acetic acid In dichloromethane at 0 - 20℃; Michael Addition; Molecular sieve;	100%
With L-Lysine hydrochloride; triethylamine In N,N-dimethyl-formamide at 20℃; for 3h; Knoevenagel Condensation;	98.3%
With cross-linked polystyrene-titanium tetrachloride complex In neat (no solvent) at 60℃; for 2h; Knoevenagel Condensation;	98%

furfural (98-01-1) + benzylamine (100-46-9) → N-benzyl-1-(furan-2-yl)methanimine (4393-11-7)

Conditions	Yield
With copper(II) bis(trifluoromethanesulfonate) In water at 20℃; for 0.0166667h;	100%
In water at 20℃; for 2h;	93%
In dichloromethane Inert atmosphere; Molecular sieve;	81%

furfural (98-01-1) + malononitrile (109-77-3) → 2-cyano-3-(2-furanyl)acrylonitrile (3237-22-7)

Conditions	Yield
With 1-butyl-1,4-diazabicyclo[2.2.2]octanylium hydrotetrafluoroborate In water at 20℃; for 0.0166667h; Knoevenagel condensation;	100%
With 1,4-diaza-bicyclo[2.2.2]octane In water at 20℃; for 0.0166667h; Knoevenagel Condensation; Green chemistry;	100%
With hydroquinone; p-benzoquinone In water at 20℃; for 3h; Reagent/catalyst; Knoevenagel Condensation; Inert atmosphere; Sealed tube;	100%

furfural (98-01-1) + trimethyl orthoformate (149-73-5) → 2-furaldehyde dimethyl acetal (1453-62-9)

Conditions	Yield
With Yb(III)-coordinated adamantane-based porous polymer In methanol at 20℃; for 12h; Catalytic behavior; Reagent/catalyst;	100%
indium(III) triflate In dichloromethane at 20℃; for 0.0833333h;	99%
With cerium triflate In methanol at 20℃; for 0.0333333h;	99%

furfural (98-01-1) → Tetrahydrofurfuryl alcohol (97-99-4)

Conditions	Yield
With hydrogen In ethanol at 60℃; under 15001.5 Torr; for 4h; Catalytic behavior; Reagent/catalyst; Temperature; Solvent; Pressure; Autoclave; Green chemistry;	100%
With hydrogen In butan-1-ol at 80℃; under 30003 Torr; for 5h; Catalytic behavior; Temperature; Reagent/catalyst;	99%
With hydrogen In isopropyl alcohol at 179.84℃; under 22502.3 Torr; for 1.25h; Reagent/catalyst;	99%

furfural (98-01-1) → 2-methylfuran (534-22-5)

Conditions	Yield
With hydrogen under 2250.23 Torr; for 15h;	100%
With hydrogen at 200℃; under 760.051 Torr;	95.5%
With hydrogen at 120℃; under 760.051 Torr; for 24h; Catalytic behavior; Reagent/catalyst; Temperature;	94.5%

furfural (98-01-1) → (2-furyl)methyl alcohol (98-00-0)

Conditions	Yield
With Pt(3)Co(3)/C; hydrogen In water at 35℃; under 750.075 Torr; for 10h; Reagent/catalyst; Pressure; Temperature; Solvent; Concentration;	100%
With HRO/TiO2; hydrogen In water at 150℃; under 15001.5 Torr; for 3h;	100%
With hydrogen In isopropyl alcohol at 179.84℃; under 22502.3 Torr; for 1.25h; Reagent/catalyst;	100%

furfural (98-01-1) → 5-hydroxy-2-(5H)-furanone (14032-66-7)

Conditions	Yield
With methanol; oxygen Irradiation;	100%
With oxygen; methylene blue In methanol at -78 - 20℃; for 23h; Irradiation;	98%
With oxygen; Rose Bengal lactone In methanol at 20℃; for 24h; Photolysis;	93%

furfural (98-01-1) → furan-2-ylmethanamine (617-89-0)

Conditions	Yield
With ammonia; hydrogen In tetrahydrofuran at 80℃; for 2h; Autoclave;	100%
With ammonia; hydrogen In methanol at 30℃; for 24h; Autoclave;	91%
With ammonium hydroxide; Ni6AlO(z); hydrogen at 100℃; under 3000.3 Torr; for 5h; Autoclave;	90%

furfural (98-01-1) → furan-2-carbaldehyde oxime (620-03-1)

Conditions	Yield
With pyridine; hydroxylamine hydrochloride In ethanol	100%
With hydroxylamine hydrochloride In ethanol; water for 0.166667h; Microwave irradiation;	89%
With N-hydroxyphthalimide In water at 90℃; for 3h; Sealed tube;	89%

furfural (98-01-1) → 1,2-di-furan-2-yl-ethane-1,2-diol (4464-77-1, 69314-24-5, 69314-25-6, 116204-42-3)

Conditions	Yield
With tris(2,2’-bipyridine)ruthenium(II); ascorbate In water for 3h; pH=12.7; Irradiation;	100%
With ammonium chloride; magnesium Ambient temperature;	92%
With triethylammonium formate; magnesium In methanol; water at 25℃; for 0.333333h;	74%

furfural (98-01-1) + 1.3-propanedithiol (109-80-8) → 2-(1,3-dithian-2-yl)furan (67421-75-4)

Conditions	Yield
With lithium tetrafluoroborate at 0℃; for 5h;	100%
With amberlyst-15 In acetonitrile for 1h;	99.92%
With dimethylbromosulphonium bromide at 20℃; for 0.0833333h;	98%

furfural (98-01-1) + diethoxyphosphoryl-acetic acid ethyl ester (867-13-0) → ethyl (E)-3-(2-furyl)prop-2-enoate (623-20-1)

Conditions	Yield
With potassium carbonate In neat (no solvent) Mechanism; var. other bases, effect of water;	100%
With water; barium dihydroxide In 1,4-dioxane at 70℃; for 0.416667h;	100%
With water; barium dihydroxide In 1,4-dioxane at 70℃; for 0.416667h; Product distribution; other catalyst, other solvents, influence of water;	100%

furfural (98-01-1) + hydrogen cyanide (74-90-8) → (S)-2-(2'-furyl)-2-hydroxy-acetonitrile (10017-07-9)

Conditions	Yield
With (R)-oxynitrilase (almond meal) In di-isopropyl ether at 4℃; for 48h;	100%
With almond meal ((R)-oxynitrilase) In di-isopropyl ether at 4 - 30℃;	100%
With almond meal In di-isopropyl ether at 15℃;	100%

furfural (98-01-1) + trimethylsilyl cyanide (7677-24-9) → 2-(2-furyl)-2-(trimethylsilyloxy)acetonitrile (40861-56-1)

Conditions	Yield
With Eu2(benzene-1,2,3,4,5,6-hexacarboxylate)(H2O)3 In acetonitrile at 20 - 100℃; for 1h;	100%
With 1-methoxy-2-methyl-1-(trimethylsiloxy)propene at 19℃; for 10h;	99%
With potassium phtalimide at 20℃; for 1.16667h; solvent-free;	99%

furfural (98-01-1) + diethyl 1-cyanomethylphosphonate (2537-48-6) → (E)-3-(2-furyl)acrylonitrile (6125-63-9)

Conditions	Yield
With water; barium dihydroxide In 1,4-dioxane at 70℃; for 0.666667h;	100%
Stage #1: diethyl 1-cyanomethylphosphonate With sodium hydride In tetrahydrofuran at 20℃; for 1h; Inert atmosphere; Stage #2: furfural In tetrahydrofuran at 28℃;
Stage #1: diethyl 1-cyanomethylphosphonate With sodium hydride In tetrahydrofuran; mineral oil at 0℃; for 0.5h; Stage #2: furfural In tetrahydrofuran; mineral oil at 0 - 25℃; for 2h;

furfural (98-01-1) + 1-(Hydroxyaminomethyl)-1-cyclohexanol (45732-93-2) → N-Furfuryliden-(1-hydroxycyclohexyl)methanamin-N-oxid (84966-16-5)

Conditions	Yield
In ethanol Ambient temperature;	100%

furfural (98-01-1) + (R)-Phenylglycinol (56613-80-0) → (R)-2-{[1-Furan-2-yl-meth-(E)-ylidene]-amino}-2-phenyl-ethanol (139437-47-1)

Conditions	Yield
With magnesium sulfate In dichloromethane at 20℃; for 12h;	100%
In benzene Heating;	88%
In benzene Heating;	85%
With magnesium sulfate In dichloromethane
In toluene Condensation; Heating;

furfural (98-01-1) + trimethylsulphonium bromide (3084-53-5) → 2-furyloxirane (2745-17-7)

Conditions	Yield
With potassium hydroxide In neat (no solvent) Mechanism; var. other bases, effect of water;	100%
With potassium hydroxide In water; acetonitrile	98%
With potassium hydroxide; water In acetonitrile at 40℃; for 0.833333h; Product distribution;	93%

furfural (98-01-1) + vinyl magnesium bromide (1826-67-1) → 1-(furan-2-yl)-2-propen-1-ol (119619-38-4)

Conditions	Yield
In tetrahydrofuran at 0℃; for 1h; Inert atmosphere;	100%
In tetrahydrofuran at 0 - 20℃; Inert atmosphere;	98%
In tetrahydrofuran at 0 - 20℃; Inert atmosphere;	92%

furfural (98-01-1) + sodium cyanide (143-33-9) + chloroformic acid ethyl ester (541-41-3) → carbonic acid, cyano(2-furyl)methyl ethyl ester (20893-23-6)

Conditions	Yield
With tetrabutyl-ammonium chloride In dichloromethane; water Heating;	100%

furfural (98-01-1) + m-Anisidine (536-90-3) → N-(furan-2-ylmethylene)-3-methoxyaniline (95124-20-2)

Conditions	Yield
In methanol at 20℃; for 24h;	100%
for 2h; Yield given;
With magnesium sulfate In ethanol at 20℃;

furfural (98-01-1) + 4-penten-1-ylmagnesium bromide (34164-50-6) → (+/-)-1-(furan-2-yl)hex-5-en-1-ol (106549-86-4, 84735-65-9)

Conditions	Yield
In tetrahydrofuran at 0℃;	100%
In tetrahydrofuran at 0 - 20℃; for 2h; Inert atmosphere;	86%
In tetrahydrofuran at 0℃;	73%

Upstream product

• 110-00-9 furan 
• 74-90-8 hydrogen cyanide 
• 68-12-2 N,N-dimethyl-formamide 
• 98-00-0 (2-furyl)methyl alcohol 
• 91-22-5 quinoline 
• 99-65-0 meta-dinitrobenzene 
• 497-19-8 sodium carbonate 
• 67-47-0 5-hydroxymethyl-2-furfuraldehyde 
• 58-86-6 D-xylose 
• 61-90-5 L-leucine 
• 5328-37-0 L-arabinose 
• 613-75-2 (furan-2-yl)methylene diacetate 
• 87-89-8 D-myo-inositol 
• 64-17-5 ethanol 

Downstream Products

• 1192-62-7 1-(2-furyl)-1-ethanone 
• 1883-27-8 dimethyl(furan-2-yl(hydroxy)methyl)phosphonate 
• 61222-94-4 2-benzoyl-3-(2-furyl)prop-2-enenitrile 
• 3194-15-8 2-propionylfuran 
• 6975-58-2 5-((Z)-furfurylidene)-2-morpholino-thiazol-4-one 
• 141632-19-1 (E)-2-(2-(furan-2-yl)vinyl)pyridine 
• 66909-43-1 (E)-α-(2-furylmethylene)-γ-butyrolactone 
• 37961-96-9 furan-2-carboxylic acid N'-(furan-2-ylmethylene)hydrazide 
• 64264-45-5 (3E)-3-(2-furylmethylidene)-1H-indol-2(3H)-one 
• 777-34-4 1-Amino-N-<5-nitro-furfur-2-yliden>-hydantoin 
• 30608-81-2 1-benzofuran-2-yl-3-furan-2-yl-propenone 
• 27406-36-6 5-(2-furfurylidene)barbituric acid 
• 98-00-0 (2-furyl)methyl alcohol 
• 134538-48-0 (E)-2-(2-nitroprop-1-en-1-yl)furan 

Relevant academic research and scientific papers

Mesoporous tantalum phosphates: Preparation, acidity and catalytic performance for xylose dehydration to produce furfural

Mesoporous tantalum phosphates (TaOPO4-m) with varying P/Ta molar ratios (m = 0.41-0.89) were prepared, comprehensively characterized by ICP-AES, N2 physisorption, small-angle XRD, TEM, Raman, FT-IR, NH3-TPD and IR of pyridine adsorption and employed to catalyze the dehydration of xylose to produce furfural in a biphasic batch reactor. The physicochemical properties of these TaOPO4-m samples were affected significantly by variation of m. More ordered mesopores were formed in the sample with a higher m. On the other hand, the density of acidity decreased but the ratio of Br?nsted acidity to Lewis acidity (B/L) increased with the increase in m. TaOPO4-0.84, which showed adequate mesoporosity and a high B/L ratio, was identified as the best performing catalyst among these TaOPO4-m catalysts in terms of high furfural selectivity (ca. 72 mol%). Correlating the catalyst performance with its acid property showed that the xylose consumption rate decreased with the increasing B/L ratio, while furfural selectivity showed a volcano-type dependence on the B/L ratio. Besides, the huge decrease in the furfural selectivity after poisoning the Br?nsted acid sites by adding 2,6-dimethyl pyridine revealed a kind of Br?nsted acid catalysis for selective furfural production.

Dehydration of xylose over sulfated tin oxide catalyst: Influences of the preparation conditions on the structural properties and catalytic performance

Various sulfated metal oxides were tested as solid acid catalyst for the dehydration of xylose to furfural under milder conditions. On the basis of our findings that sulfated tin oxide exhibited the highest catalytic activity, the effects of the content of SO42- group and the calcination temperature on the structural properties and catalytic performance were investigated, and the reusability of the sulfated tin oxide catalyst was evaluated. The acid property on the sulfated tin oxide catalyst was characterized by in situ FT-IR observations of the CO-adsorbed sample. Finally, the reaction mechanism of dehydration of xylose over the SO4 2-/SnO2 catalyst was considered.

Improving Biocatalytic Synthesis of Furfuryl Alcohol by Effective Conversion of D-Xylose into Furfural with Tin-Loaded Sulfonated Carbon Nanotube in Cyclopentylmethyl Ether-Water Media

Carbon nanotube (CNT) was utilized as as the precursor to synthesize solid acid (tin-loaded sulfonated carbon nanotube, SO42?/SnO2-CNT) for catalyzing D-xylose into furfural. Fourier transform infrared spectroscopy, Roman spectroscopy, X-ray diffraction analysis, and scanning electron microscope techniques were used for characterizing SO42?/SnO2-CNT. Different loading of D-xylose (20–100?g/L) were converted into furfural (81.6–299.1?mM) at 41.9–61.2% yield by SO42?/SnO2-CNT (3.5 wt%) within 15?min at 180 °C in cyclopentylmethyl ether-water (1:2, v:v) biphasic media. Subsequently, whole-cells of recombinant Escherichia coli CG-19 cells expressing reductase catalyzed D-xylose-derived furfural at 35 ℃ and pH 7.5. Within 3?h, the prepared D-xylose (81.6–299.1?mM) could be converted into furfuryl alcohol at 32.7–61.2% yield (based on the D-xylose loading). Sequential conversion of D-xylose with SO42?/SnO2-CNT and reductase catalysts was established for the effective production of furfuryl alcohol. Graphic Abstract: [Figure not available: see fulltext.]

Conversion of xylose, xylan and rice husk into furfural via betaine and formic acid mixture as novel homogeneous catalyst in biphasic system by microwave-assisted dehydration

Dehydration of D-xylose and direct transformation of xylan into furfural were achieved by means of betaine-formic acid (HCOOH) catalytic system. All reactions were microwave-assisted and carried out in a CPME-water biphasic system. At 170?°C, in a pH range between 1.9 and 2.3, highest yields of 80% and 76% were obtained respectively for the pentose and the polysaccharide. Time dependence of the dehydration and influence of the temperature on the reaction kinetics were studied. Besides, at 190?°C, using the optimized condition of the reaction, rice husk was also employed as a source of furfural with a single stage reaction.

Dehydration of D-xylose into furfural over bimetallic salts of heteropolyacid in DMSO/H2O mixture

Dehydration of D-xylose to yield furfural was carried out using bimetallic salts of a heteropolyacid as the catalyst at 160–220 °C in the DMSO/H2O mixtures. The effect of Sn/Cs molar ratio of the bimetallic salts of 12-tungstophosphoric acid (PW) obtained by ultrasound-assisted coprecipitation on dehydration of D-xylose was investigated. The resultant catalysts were characterized by X-ray diffraction, N2 adsorption, field emission scanning electron microscopy and energy dispersive X-ray (EDX). It was found that the Sn-Cs codoped PW catalysts retained the Keggin crystal structure of PW. Sn0.625Cs0.5PW was the most active catalyst in the dehydration of D-xylose into furfural. The maximum D-xylose conversion (close to 100 wt %) and furfural yield (63 wt %) were achieved at 200 °C for 3 h in DMSO/H2O mixtures. It was found that 16.7 wt % Sn0.625Cs0.5PW on a chitosan-derived support displayed similar catalytic activity to that of Sn0.625Cs0.5PW and good stability after recycling six times.

The role of xylulose as an intermediate in xylose conversion to furfural: insights via experiments and kinetic modelling

An experimental work has been performed to study the relevance of xylulose as an intermediate in xylose conversion to furfural in aqueous solution. The furfural formation was investigated at the temperature range from 180 to 220 °C during non-catalyzed and acid-catalyzed conversion of xylose in a stirred microwave-assisted batch reactor. The separate experiments on xylulose and furfural conversions were carried out under similar conditions. The maximum furfural yields obtained from xylose were 48 mol% and 65 mol% for the non-catalyzed and the acid-catalyzed processes, respectively. It was shown that the furfural yield is significantly lower from xylulose than from xylose. Furthermore, the effects of initial xylose concentration and the formation of xylulose were investigated in a mechanistic modeling study. A new reaction mechanism was developed taking into account the xylulose formation from xylose. Based on the experimental results and the proposed reaction model, it was concluded that xylose isomerization to xylulose with subsequent furfural formation is not a primary reaction pathway. The obtained kinetic parameters were further used for plug flow reactor simulations to evaluate furfural yields achievable by an optimized continuous operation.

Furfural production in a biphasic system using a carbonaceous solid acid catalyst

The formation of furfural from xylose was investigated under heterogeneously catalyzed conditions with Starbon450-SO3H as a catalyst in a biphasic system. Experiments were performed based on a statistical experimental design. The variables considered were time and temperature. Starbon450-SO3H was characterized by scanning electron microscopy, N2-physisorption, thermogravimetric analysis, diffuse reflectance infrared Fourier transform, Raman spectroscopy, pyridine titration and X-ray photoelectron spectroscopy. The results indicate that sulfonated Starbon450-SO3H can be an effective solid acid catalyst for furfural formation. A maximum furfural yield and selectivity of 70 mol% was achieved at complete xylose conversion under optimum experimental conditions. The present paper suggests that functionalized Starbon450-SO3H can be employed as an efficient solid acid catalyst that has significant hydrothermal stability and can be reused for several cycles to produce furfural from xylose.

Synergy effect between solid acid catalysts and concentrated carboxylic acids solutions for efficient furfural production from xylose

An efficient furfural formation from xylose was demonstrated combining a concentrated aqueous solution of acetic acid and solid acid catalysts. Higher furfural yields and selectivities were obtained by comparison to the catalytic performances obtained in pure water. The evident synergy effect observed at 150 °C between the aqueous carboxylic acid solution and the solid acid catalysts is tentatively explained by the occurrence of two phenomena: 1) the contribution of Lewis acid sites which would operate in cooperation with the homogeneous weak Br?nsted acidity brought by the aqueous acetic acid solution. According to the literature, the two steps mechanism involving the xylose-xylulose isomerization over Lewis acid sites and the successive Br?nsted acid catalyzed cyclodehydration to furfural would be the prevailing reaction pathway in the heterogeneous-homogenous catalytic system at 150 °C. 2) an enhancement of the surface solid acid coverage by the carbohydrate and furfural owing to the presence of carboxylic acid in the aqueous solution as shown by comparative liquid phase adsorption experiments done in pure water and in aqueous acetic acid solutions. Among a series of solid acid catalysts, ZrW, Cs2HPW12O40, HY (Si/Al = 15), K10 and NbOH, the latter one, NbOH used non-calcinated was shown to be active, selective and stable in the aqueous acetic acid media. HY and K10 are as active and selective for furfural formation but suffer for a strong Al leaching which precludes their utilization as true solid acid catalyst in acetic acid media.

Furfural production from xylose + glucose feedings and simultaneous N 2-stripping

The current furfural manufacturing process is based on homogeneous catalysts as well as steam as the stripping agent. Novel xylose-dehydration research studies include heterogeneous catalysts with high acidity and tailored selectivity. This work aims to evaluate the effect of additional glucose with the xylose feeding during simultaneous N2-stripping of furfural catalyzed by ion-exchange resins. Given the low batch performance of Amberlyst 70, the N2-stripping data showed high furfural yields and selectivity in the condensate stream. The different continuous feeding configurations showed that xylose/glucose ratios similar to the real pentosan-rich biomass could be fed achieving furfural yields of 75% at 200 °C. Moreover, the proposed study serves as a preliminary study to achieve high xylose conversion and relatively low glucose dehydration rates, showing its potential as a possible future process for the upgrading of carbohydrates to furan-based fuel additives.

Efficient, stable, and reusable silicoaluminophosphate for the one-pot production of furfural from hemicellulose

Development of stable, reusable, and water-tolerant solid acid catalysts in the conversion of polysaccharides to give value-added chemicals is vital because catalysts are prone to undergo morphological changes during the reactions. With the anticipation that silicoaluminophosphate (SAPO) catalysts will have higher hydrothermal stability, those were synthesized, characterized, and employed in a one-pot conversion of hemicellulose. SAPO-44 catalyst at 170 C within 8 h could give 63% furfural yield with 88% mass balance and showed similar activity up to at least 8 catalytic cycles. The morphological studies revealed that SAPO catalysts having hydrophilic characteristics are stable under reaction conditions.