γ-Valerolactone (GVL) is an organic compound 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 ...

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 is a potential fuel and green solvent. GVL behaves as a

prodrug A prodrug is a medication or compound that, after intake, is metabolized (i.e., converted within the body) into a pharmacologically active drug. Instead of administering a drug directly, a corresponding prodrug can be used to improve how the drug ...

γ-hydroxyvaleric acid γ-Hydroxyvaleric acid (GHV), also known as 4-methyl-GHB, is a designer drug related to γ-hydroxybutyric acid (GHB). It is sometimes seen on the grey market as a legal alternative to GHB, but with lower potency and higher toxicity, properties ...

(GHV), a

drug A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via insuffla ...

with similar effects to those of γ-hydroxybutyric acid (GHB), albeit with less potency in comparison. Because GHB is controlled in many parts of the world, while GVL is not, GVL has gained popularity as a legal substitute for GHB.

Synthesis

GVL is produced from levulinic acid, which is obtained from hexoses. In a typical process, cellulosic

biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...

es, such as corn stover, sawgrass, or wood, is hydrolysed into glucose and other sugars using

acid catalyst In acid catalysis and base catalysis, a chemical reaction is catalyzed by an acid or a base. By Brønsted–Lowry acid–base theory, the acid is the proton (hydrogen ion, H+) donor and the base is the proton acceptor. Typical reactions catalyze ...

s. The resulting glucose can then be dehydrated via

hydroxymethylfurfural Hydroxymethylfurfural (HMF), also 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 both water ...

to yield

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 ...

and levulinic acid, which cyclises to intermediate unsaturated ring compounds, which can then be hydrogenated to ''gamma''-valerolactone, which has potential applications as a liquid fuel. :

Potential applications

GVL has been identified as a potential green solvent. Because of its herbal odor, it is used in the perfume and flavor industries. It is a structural isomer of δ-valerolactone.

Potential fuel

Since it is readily obtained from glucose, GVL has long been identified as a potential "green fuel." GVL retains 97% of the energy of glucose and can be blended by itself in gasoline where it performs comparably to ethanol/gasoline mixtures. However, due to blending limits for use in conventional combustion engines, it may be more efficient to convert GVL into liquid alkenes (or

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which ...

s). The first step in this process is the ring-opening of GVL to yield a mixture of

pentenoic acid Pentenoic acid is any of five mono-carboxylic acids whose molecule has an unbranched chain of five carbons connected by three single bonds and one double bond. That is, any compound with one of the formulas (2-pentenoic), (3-pentenoic), or ( ...

s. These acids can then be

decarboxylated Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is t ...

to produce butene and CO₂. These conversions can be performed with zeolite catalysts. After this stream is dehydrated, the products can be

oligomer In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers.Quote: ''Oligomer molecule: A molecule of intermediate relativ ...

ized at elevated pressures in the presence of a common acid-catalyst to yield alkenes with higher molecular weights, targeted for gasoline and other fuel applications. One of the main advantages that allows GVL to be a practical

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 ...

is that it is relatively inexpensive to produce. Using a cheap

feedstock A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feedst ...

, this biofuel can be produced at prices between 2-3 US$/gallon. The conversion of GVL to transportation fuel capable alkenes only requires a system containing two flow reactors, two phase separators, and a simple pumping arrangement for the delivery of an aqueous GVL feed. Since the use of

precious metal Precious metals are rare, naturally occurring metallic chemical elements of high economic value. Chemically, the precious metals tend to be less reactive than most elements (see noble metal). They are usually ductile and have a high lustre. ...

catalysts is not required, this also decreases the total price of fuel production.

Potential production of biomass-derived fuels

Apart from its value as a potential fuel in its own right, gamma-valerolactone has shown promise in laboratory-scale thermocatalytic production of soluble carbohydrates from corn

stover Stover are the leaves and stalks of field crops, such as corn (maize), sorghum or soybean that are commonly left in a field after harvesting the grain. It is similar to straw, the residue left after any cereal grain or grass has been harvested a ...

and wood at high yields. The biomass reacts in a solvent mixture of water, dilute sulfuric acid, and gamma-valerolactone, itself derived from biomass. The gamma-valerolactone promotes thermocatalytic hydrolysis into monosaccharides by complete solubilization of the raw material, including lignins. The saccharide products can be recovered from the lactone into water solution by antisolvent addition of salt or liquid carbon dioxide. The product can be used as feedstock for producing furans or ethanol at high yield, while the gamma-valerolactone is returned to the catalytic cycle.

Membrane Fabrication

Gamma-Valerolactone has been studied and shown the potential to prepare dope solutions for the fabrication of polymeric membranes. Due to the toxicity of the traditional solvents, green solvents were investigated in recent years. Due to its environmentally friendly profile, Gamma-Valerolactone showed the potential to fabricate polysulfone membranes as a co-solvent.

References

External links

; General Safety Information
gamma-Valerolactone MSDS by Sciencelab.com
{{DEFAULTSORT:Valerolactone, gamma- Gamma-lactones GABAB receptor agonists GHB receptor agonists Designer drugs Hypnotics Prodrugs Solvents