2,5-Dimethylfuran is a

heterocyclic compound A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, proper ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

(CH₃)₂C₄H₂O. Although often abbreviated DMF, it should not be confused with

dimethylformamide Dimethylformamide, DMF is an organic compound with the chemical formula . Its structure is . Commonly abbreviated as DMF (although this initialism is sometimes used for 2,5-dimethylfuran, dimethylfuran, or dimethyl fumarate), this colourless liqui ...

. A derivative of

furan Furan is a Heterocyclic compound, heterocyclic organic compound, consisting of a five-membered aromatic Ring (chemistry), ring with four carbon Atom, atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as f ...

, this simple compound is a potential

biofuel Biofuel is a fuel that is produced over a short time span from Biomass (energy), biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricu ...

, being derivable from cellulose.

Production

Fructose Fructose (), or fruit sugar, is a Ketose, ketonic monosaccharide, simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and gal ...

can be converted into 2,5-dimethylfuran in a

catalytic Catalysis () is the increase in reaction rate, rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst ...

biomass-to-liquid process. The conversion of fructose to DMF proceeds via

hydroxymethylfurfural Hydroxymethylfurfural (HMF), also known as 5-(hydroxymethyl)furfural, is an organic compound formed by the dehydration of reducing sugars. It is a white low-melting solid (although commercial samples are often yellow) which is highly soluble in b ...

. Fructose is obtainable from glucose, a building block in cellulose.

Potential as a biofuel

DMF has a number of attractions as a

. It has an

energy density In physics, energy density is the quotient between the amount of energy stored in a given system or contained in a given region of space and the volume of the system or region considered. Often only the ''useful'' or extractable energy is measure ...

40% greater than that of

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

, making it comparable to

gasoline Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...

(petrol). It is also chemically stable and, being

insoluble In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solub ...

in water, does not absorb moisture from the atmosphere. Evaporating dimethylfuran during the production process also requires around one third less energy than the evaporation of ethanol, although it has a boiling point some 14 °C higher, at 92 °C, compared to 78 °C for ethanol. The ability to efficiently and rapidly produce dimethylfuran from fructose, found in

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

and some

root vegetable Root vegetables are underground plant parts eaten by humans or animals as food. In agricultural and culinary terminology, the term applies to true roots, such as taproots and root tubers, as well as non-roots such as bulbs, corms, rhizomes, and ...

s, or from glucose, which can be derived from

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...

and

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

- all widely available in nature - adds to the attraction of dimethylfuran, although safety issues must be examined. Bioethanol and

biodiesel Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats. The roots of bi ...

are currently the leading liquid biofuels. The stoichiometric air/fuel ratio of dimethylfuran is 10.72, compared to ethanol at 8.95 and gasoline at 14.56. This means that burning dimethylfuran requires approximately 33% less air than the same quantity of gasoline, but approximately 20% more air than the same quantity of ethanol. The

calorific value The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The ''calorific value'' is the total energy release ...

of liquid dimethylfuran is 33.7 MJ/kg, compared to 26.9 MJ/kg for ethanol and 43.2 MJ/kg for gasoline. The research octane number (RON) of dimethylfuran is 119. The

latent heat of vaporization In thermodynamics, the enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy) that must be added to a liquid substance to transform a quantity of that sub ...

at 20 °C is 31.91 kJ/mol. Recent tests in a single-cylinder gasoline engine found that the thermal efficiency of burning dimethylfuran is similar to that of gasoline.

Other uses

2,5-Dimethylfuran serves as a

scavenger Scavengers are animals that consume Corpse decomposition, dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a he ...

for

singlet oxygen Singlet oxygen, systematically named dioxygen(singlet) and dioxidene, is a gaseous inorganic chemistry, inorganic chemical with the formula O=O (also written as or ), which is in a quantum state where all electrons are Radical (chemistry), spin p ...

, a property which has been exploited for the determination of singlet oxygen in natural waters. The mechanism involves a Diels-Alder reaction followed by

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

, ultimately leading to diacetylethylene and

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

as products. More recently,

furfuryl alcohol Furfuryl alcohol is an organic compound containing a furan substituted with a hydroxymethyl group. It is a colorless liquid, but aged samples appear amber. It possesses a faint odor of burning and a bitter taste. It is miscible with but unstabl ...

has been used for the same purpose. 2,5-Dimethylfuran has also been proposed as an internal standard for

NMR spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique based on re-orientation of atomic nuclei with non-zero nuclear spins in an external magnetic f ...

. 2,5-Dimethylfuran has singlets in its ¹H NMR spectrum at δ 2.2 and 5.8; the singlets give reliable integrations, while the positions of the peaks do not interfere with many analytes. The compound also has an appropriate boiling point of 92 °C which prevents evaporative losses, yet is easily removed.

Role in food chemistry

2,5-Dimethylfuran forms upon thermal degradation of some sugars and has been identified in trace amounts as a component of

caramelized Caramelization (or caramelisation) is a process of browning of sugar used extensively in cooking for the resulting butter-like flavor and brown color. The brown colors are produced by three groups of polymers: (C24H36O18), (C36H50O25), and ...

sugars.

Toxicology

2,5-Dimethylfuran plays a role in the mechanism for the

neurotoxicity Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specifical ...

of hexane in humans. Together with

hexane-2,5-dione 2,5-Hexanedione (Acetonylacetone) is an aliphatic diketone. It is a colorless liquid. In humans, it is a toxic metabolite of hexane and of 2-hexanone. Symptoms of poisoning The chronic toxicity of hexane is attributed to hexane-2,5-dione. The s ...

and 4,5-dihydroxy-2-hexanone, it is one of the main

metabolite In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...

s of

hexane Hexane () or ''n''-hexane is an organic compound, a straight-chain alkane with six carbon atoms and the molecular formula C6H14. Hexane is a colorless liquid, odorless when pure, and with a boiling point of approximately . It is widely used as ...

. 2,5-Dimethylfuran has been identified as one of the components of

cigar A cigar is a rolled bundle of dried and Fermentation, fermented tobacco leaves made to be Tobacco smoking, smoked. Cigars are produced in a variety of sizes and shapes. Since the 20th century, almost all cigars are made of three distinct comp ...

smoke Smoke is an aerosol (a suspension of airborne particulates and gases) emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwante ...

with low ciliary toxicity (ability to adversely affect the

cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

in the

respiratory tract The respiratory tract is the subdivision of the respiratory system involved with the process of conducting air to the alveoli for the purposes of gas exchange in mammals. The respiratory tract is lined with respiratory epithelium as respirato ...

that are responsible for removing foreign particles). Its blood concentration can be used as a

biomarker In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, ...

for

smoking Smoking is a practice in which a substance is combusted, and the resulting smoke is typically inhaled to be tasted and absorbed into the bloodstream of a person. Most commonly, the substance used is the dried leaves of the tobacco plant, whi ...

. Comparison of Safety Data Sheets shows that human handling of 2,5-dimethylfuran is approximately as hazardous as handling gasoline.

References

{{DEFAULTSORT:Dimethylfuran, 2, 5- Furans Biofuels