Levulinic acid

Levulinic acid^[1]

Names
IUPAC name 4-Oxopentanoic acid
Other names Levulinic acid, Laevulinic acid, β-Acetylpropionic acid, 3-Acetopropionic acid, β-acetylpropionic acid, γ-ketovaleric acid, 4-oxopentanoic acid
Identifiers
CAS Number	123-76-2 Y
ChEBI	CHEBI:45630 Y
ChEMBL	ChEMBL1235931 N
ChemSpider	11091 Y
DrugBank	DB02239 Y
Jmol interactive 3D	Image
PubChem	11579
UNII	RYX5QG61EI Y
InChI InChI=1S/C5H8O3/c1-4(6)2-3-5(7)8/h2-3H2,1H3,(H,7,8) Y Key: JOOXCMJARBKPKM-UHFFFAOYSA-N Y InChI=1/C5H8O3/c1-4(6)2-3-5(7)8/h2-3H2,1H3,(H,7,8) Key: JOOXCMJARBKPKM-UHFFFAOYAR
SMILES CC(=O)CCC(=O)O
Properties
Chemical formula	C5H8O3
Molar mass	116.11 g/mol
Density	1.1447 g/cm3
Melting point	33 to 35 °C (91 to 95 °F; 306 to 308 K)
Boiling point	245 to 246 °C (473 to 475 °F; 518 to 519 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Levulinic acid, or 4-oxopentanoic acid, is an organic compound with the formula CH₃C(O)CH₂CH₂CO₂H. It is classified as a keto acid. This white crystalline solid is soluble in water and polar organic solvents. It is derived from degradation of cellulose and is a potential precursor to biofuels.^[2]

History

In 1840 the Dutch Professor G.J. Mulder mentioned levulinic acid for the first time.^[3] He synthesized it by heating fructose with hydrochloride. The former term “levulose” for fructose gave the levulinic acid its name. Although levulinic acid has been well known since the 1870s, it has never reached a commercial use in a significant volume. First commercial production of levulinic acid has begun as a batch wise process in an autoclave by A.E. Statley in the 1940s.^[4] In 1953 the US-American company Quaker Oats developed a continuous process for the production of levulinic acid.^[5] In 1956 it was identified as a platform chemical with high potential^[6] and in 2004 the US Department of Energy (U.S. DoE) identified levulinic acid by screening approximately 300 substances as one of the 12 potential platform chemicals in the biorefinery concept.^[7]

Synthesis

The original synthesis of levulinic acid is done by heating hexoses (glucose, fructose or starch) in diluted hydrogenchloride or sulfuric acid.^[3][8][9] The yield depends on the nature of the acid, acid concentration, temperature and pressure.^[10] In addition to formic acid further, partly insoluble, by-products are produced. These are deeply colored and their complete removal is a challenge for most technologies.

Many concepts for the commercial production of levulinic acid are based on a strong acid technology. The processes are conducted in a continuous manner using lignocellulose as inexpensive starting material which was impregnated by dilute mineral acid and transferred into a high pressure reactor where it was heated with steam to allow the reaction to form levulinic acid to take place. After cooling of the reaction mixture and filtration of the solid by-products the product, levulinic acid, is separated from the mineral acidic catalyst via extraction avoiding neutralization of the acid catalyst. This allows the recycle of the acidic catalyst while the levulinic acid could be purified from a mineral acid free an organic solvent. Pure levulinic acid was isolated by evaporation of the extraction solvent and distillation of levulinic acid. Companies who developed technology based on this concept are e.g. Biofine,^[11] DSM,^[12] Segetis^[13] and GFBiochemicals. The latter has started the commercial production of levulinic acid in 2015 at a production scale of 2,000 MT/a in Caserta, Italy.^[14][15] Thus, “Caserta is now the world’s largest operational production plant for levulinic acid”.^{[15] [16]}

Reactions and applications

Levulinic acid is used as a precursor for pharmaceuticals, plasticizers, and various other additives.^[17] Furthermore, it is recognized as a building block or starting material for a wide number of compounds.^[18] This family addresses a number of large volume chemical markets. For example as potential biofuels including γ-Valerolactone, 2-Methyl-THF, ethyl levulinate.^[7]

Other occurrence and niche uses

Levulinic acid is used in cigarettes to increase nicotine delivery in smoke and binding of nicotine to neural receptors.^[19]

Safety

Levulinic acid is relatively nontoxic, with an LD₅₀ of 1850 mg/kg.^[17]

References

•  This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press.