The Molecular Structure of  Furfural (CAS NO.98-01-1):

Empirical Formula: C₅H₄O₂
Molecular Weight: 96.0841 
IUPAC: furan-2-carbaldehyde 
Nominal Mass: 96 Da
Average Mass: 96.0841 Da
Monoisotopic Mass: 96.021129 Da 
Index of Refraction: 1.515
Molar Refractivity: 25.3 cm³
Molar Volume: 83.8 cm³
Surface Tension: 36.5 dyne/cm
Density: 1.145 g/cm³
Flash Point: 58.3 °C
Enthalpy of Vaporization: 39.84 kJ/mol
Boiling Point: 161.8 °C at 760 mmHg
Vapour Pressure: 2.23 mmHg at 25°C 
Storage temp: 2-8°C
Water Solubility: 8.3 g/100 mL
FreezingPoint: -36.5°C
Sensitive: Air Sensitive 
Stability: Stable. Substances to be avoided include strong bases, strong oxidizing agents and strong acids. Flammable
Appearance: colourless to reddish-brown oily liquid with almond odour
InChI
InChI=1/C5H4O2/c6-4-5-2-1-3-7-5/h1-4H
Smiles
c1(ccco1)C=O 
Product Categories: Intermediates;API intermediates;Furans
Synonyms: 2-formylofuran ; 2-Furanaldehyde ; 2-Furancarbonal ; 2-Furancarboxaldehyde (furfural) ; 2-Furankarbaldehyd ; 2-Furfural ; 2-Furfuraldehyde ; 2-Furil-metanale  
It is a colorless oily liquid with the odor of almonds if pure , but it quickly becomes yellow when upon exposure to air . Furfural (CAS NO.98-01-1) dissolves readily in most polar organic solvents, but is only slightly soluble in either water or alkanes. When heated above 250 °C, furfural decomposes into furan and carbon monoxide, sometimes explosively.When heated in the presence of acids, furfural irreversibly solidifies into a hard thermosetting resin.

In 1832, the German chemist Johann Wolfgang D?bereiner ,first isolated furfural ,he formed a very small quantity of it 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 bran, corn, oats, and sawdust, with aqueous sulfuric acid, and he determined that this chemical had an empirical formula of C₅H₄O₂. 
In 1901, the German chemist Carl Harries deduced furfural's structure.

 Furfural (CAS NO.98-01-1) is used as a solvent in petrochemical refining to extract dienes ( used to make synthetic rubber) from other hydrocarbons . Furfural (CAS NO.98-01-1), also can be used either by themselves or in together with phenol, acetone, or urea to make solid resins. Furfural (CAS NO.98-01-1) is also used as a chemical intermediate in the production of the solvents furan and tetrahydrofuran .

In the laboratory, synthesis of furfural from corn cobs takes place by reflux with dilute sulfuric acid. China is the biggest supplier of furfural, and accounts for around half of global capacity.The total global production capacity is about 450,000 tons. 

NTP Carcinogenesis Studies (gavage); Clear Evidence: mouse NCITR*    National Cancer Institute Carcinogenesis Technical Report Series. (Bethesda, MD 20014) No. NTP-TR-382,90, . , Some Evidence: rat NCITR*    National Cancer Institute Carcinogenesis Technical Report Series. (Bethesda, MD 20014) No. NTP-TR-382 ,1990. . EPA Genetic Toxicology Program. Reported in EPA TSCA Inventory.

Confirmed carcinogen. Poison by ingestion, intraperitoneal, subcutaneous, intravenous, and intramuscular routes. Moderately toxic by inhalation and skin 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 volatility.
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.
Hazard Codes: XiT
Risk Statements: 21-23/25-36/37-40 
R21: Harmful in contact with skin
R23/25: Toxic by inhalation and if swallowed
R36/37: Irritating to eyes and respiratory system
R40: Limited evidence of a carcinogenic effect
Safety Statements: 26-36/37/39-45-1/2 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
S36/37/39: Wear suitable protective clothing, gloves and eye/face protection
S45: In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)
S1/2: Keep locked up and out of the reach of children
RIDADR: UN 1199 6.1/PG 2
WGK Germany: 2
RTECS: LT7000000
F: 1-8-10
F 1: Sensitive to air and humidity
F 8: Photosensitive
F 9: Keep under nitrogen
F 10: Keep under argon
Hazard Note: Irritant
HazardClass: 6.1
PackingGroup: II
Contact with furfural irritates the skin and respiratory tract and can cause the lungs to fill with fluid.When ingested or inhaled, furfural can cause intoxication, including euphoria, nausea, headache, dizziness, and eventual unconsciousness and death due to respiratory failure. 
Chronic skin exposure can lead to a skin allergy to the substance, as well as an unusual susceptibility to sunburn. 

OSHA PEL: TWA 2 ppm (skin)
ACGIH TLV: TWA 2 ppm (skin); Animal Carcinogen: BEI: 200 mg/g creatinine of total furoic acid in urine at end of shift
DFG MAK: Confirmed Animal Carcinogen with Unknown Relevance to Humans
DOT Classification:  3; Label: Flammable Liquid

For occupational chemical analysis use OSHA: #ID-72 or NIOSH: Furfural, 2529.