Levulinic acid, or 4-oxopentanoic acid, is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

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 betwee ...

CH₃C(O)CH₂CH₂CO₂H. It is classified as a

keto acid In organic chemistry, keto acids or ketoacids (also called oxo acids or oxoacids) are organic compounds that contain a carboxylic acid group () and a ketone group ().Franz Dietrich Klingler, Wolfgang Ebertz "Oxocarboxylic Acids" in Ullmann's E ...

. This white crystalline solid is soluble in water and polar organic solvents. It is derived from degradation of

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...

and is a potential precursor to

biofuel Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. According to the United States Energy Information Administration (E ...

s, such as

ethyl levulinate Ethyl levulinate is an organic compound with the formula CH3C(O)CH2CH2C(O)OC2H5. It is an ester derived from the keto acid levulinic acid. Ethyl levulinate can also be obtained by reaction between ethanol and furfuryl alcohol. These two synthesis ...

Synthesis

Levulinic acid was first prepared in 1840 by Dutch chemist

Gerardus Johannes Mulder Gerardus Johannes Mulder or Gerrit Jan Mulder (27 December 1802 – 18 April 1880) was a Dutch organic and analytical chemist. Life Mulder was born in Utrecht and earned a medical degree from Utrecht University. He became a reader of chemis ...

by heating

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 galacto ...

with hydrochloric acid. The first commercial production of levulinic acid began as a batchwise process in an autoclave by

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 diets ...

manufacturer A. E. Staley in the 1940s. In 1953 Quaker Oats developed a continuous process for the production of levulinic acid. In 1956 it was identified as a platform chemical with high potential. and in 2004 the US Department of Energy (U.S. DoE) identified levulinic acid as one of the 12 potential platform chemicals in the biorefinery concept. The synthesis of levulinic acid from

hexose In chemistry, a hexose is a monosaccharide (simple sugar) with six carbon atoms. The chemical formula for all hexoses is C6H12O6, and their molecular weight is 180.156 g/mol. Hexoses exist in two forms, open-chain or cyclic, that easily convert ...

s (

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

) or starch in dilute

hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbol ...

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...

. In addition to

formic acid Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...

further, partly insoluble, by-products are produced. These are deeply colored and their complete removal is a challenge for most technologies. Synthesis levulinic acid

Many concepts for the commercial production of levulinic acid are based on a strong acid technology. The processes are conducted in a continuous manner at high pressures and temperatures.

Lignocellulose Lignocellulose refers to plant dry matter (biomass), so called lignocellulosic biomass. It is the most abundantly available raw material on the Earth for the production of biofuels. It is composed of two kinds of carbohydrate polymers, cellulose a ...

is an inexpensive starting material. Levulinic acid is separated from the mineral acid

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

by extraction. Levulinic acid is purified by

distillation Distillation, or classical distillation, is the process of separation process, separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distilla ...

Reactions and applications

Levulinic acid is used as a precursor for pharmaceuticals, plasticizers, and various other additives.Franz Dietrich Klingler, Wolfgang Ebertz "Oxocarboxylic Acids" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2005, Wiley-VCH, Weinheim. The largest application of levulinic acid is its use in the production of aminolevulinic acid, a biodegradable

herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...

used in South Asia. Another key application is the use of levulinic acid in cosmetics.

Ethyl levulinate Ethyl levulinate is an organic compound with the formula CH3C(O)CH2CH2C(O)OC2H5. It is an ester derived from the keto acid levulinic acid. Ethyl levulinate can also be obtained by reaction between ethanol and furfuryl alcohol. These two synthesis ...

, a primary derivative of levulinic acid, is extensively used in fragrances and perfumes. Levulinic acid is a chemical building block or starting material for a wide variety of other compounds including

γ-valerolactone γ-Valerolactone (GVL) is an organic compound with the chemical formula, formula C5H8O2. This colourless liquid is one of the more common lactones. GVL is chiral but is usually used as the racemate. It is readily obtained from cellulosic biomass ...

and 2-methyl-THF. Levulinic acid family

Other occurrence and niche uses

Levulinic acid is used in

cigarette A cigarette is a narrow cylinder containing a combustible material, typically tobacco, that is rolled into thin paper for smoking. The cigarette is ignited at one end, causing it to smolder; the resulting smoke is orally inhaled via the opp ...

s to increase

nicotine Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As ...

delivery in smoke and binding of nicotine to neural receptors.Doris Cullen et al., ''A Guide to Deciphering the Internal Codes Used by the Tobacco Industry'', Report No. 03-05, Harvard School of Public Health, Division of Public Health Practice, Tobacco Research Program, August 2005, http://legacy.library.ucsf.edu/resources/harvard_monograph.pdf

Etymology

The former term “levulose” for fructose gave levulinic acid its name.

Safety

Levulinic acid is relatively nontoxic, with an of 1850 mg/kg.

References

* {{cite EB1911 , wstitle=Rubber , volume=23 , page=802 , first=Wyndham Rowland , last=Dunstan Keto acids