2-Methyl-2,4-pentanediol (MPD) is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

with the formula (CH₃)₂C(OH)CH₂CH(OH)CH₃. This colourless liquid is a

chiral Chirality () is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek language, Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is dist ...

diol A diol is a chemical compound containing two hydroxyl groups ( groups). An aliphatic diol may also be called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified. They are used as protecting gro ...

. It is produced industrially from

diacetone alcohol Diacetone alcohol is an organic compound with the formula CH3C(O)CH2C(OH)(CH3)2, sometimes called DAA. This colorless liquid is a common synthetic intermediate used for the preparation of other compounds, and is also used as a solvent. Synthesi ...

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or Saturated ...

.Stylianos Sifniades, Alan B. Levy, "Acetone" in ''Ullmann’s Encyclopedia of Industrial Chemistry'', Wiley-VCH, Weinheim, 2005. Total European and USA production was 15000 tonnes in 2000.SIDS Initial Assessment Report for SIAM 13: Hexylene Glycol
/ref> 2-Methyl-2,4-pentanediol exists as two enantiomers, (4''R'')-(−) and (4''S'')-(+). In the

Protein Data Bank The Protein Data Bank (PDB) is a database for the three-dimensional structural data of large biological molecules such as proteins and nucleic acids, which is overseen by the Worldwide Protein Data Bank (wwPDB). This structural data is obtained a ...

, the 3-letter code "MPD" refers to the (''S'')-(−) enantiomer, while "MRD" is used to refer to the (''R'')-(+) version. Commercial products labeled "MPD" are usually the

racemate In chemistry, a racemic mixture or racemate () is a mixture that has equal amounts (50:50) of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as r ...

,MPD at Hampton Research
MPD Product Page also sold as and referred to as "hexylene glycol".Hexylene Glycol at Sigma Aldrich
Hexylene Glycol Product PageHexylene Glycol at Jena Bioscience, Hexylene Glycol Product Page

Uses

2-Methyl-2,4-pentanediol exhibits both surfactant and emulsion-stabilizing properties. Its relatively high viscosity and low volatility are advantageous in coatings, cleansers, cosmetics, solvents, lubricants, and

hydraulic fluid A hydraulic fluid or hydraulic liquid is the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water. Examples of equipment that might use hydraulic fluids are excavators and backho ...

s.Chemicalland21.com
Hexylene glycol Although it is an irritant at higher concentrations, it is sometimes used in skin care, hair care, soap, and eye cosmetic products at concentrations ranging from 0.1% - 25%. It is biodegradable and unlikely to accumulate in the environment.

Laboratory uses

In the laboratory it is a common precipitant and

cryoprotectant A cryoprotectant is a substance used to protect biological tissue from freezing damage (i.e. that due to ice formation). Arctic and Antarctic insects, fish and amphibians create cryoprotectants ( antifreeze compounds and antifreeze proteins) in th ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

crystallography Crystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word ''crystallography'' is derived from the Ancient Greek word (; "clear ice, rock-crystal"), and (; "to write"). In J ...

.Crystallization Techniques: Additives
Enrico Stura, University of Glasgow Since hexylene glycol is compatible with polar and nonpolar molecules, it competes with the solvent in a crystallography experiment causing the protein to precipitate. Hexylene glycol is so effective in protein crystallography because its amphiphilic nature and small, flexible structure allows it to bind to many different locations on a protein secondary structure including alpha helices and beta sheets. When hexylene glycol binds to these different locations, water is removed and the protein crystals anneal, which prevents ice formation during cryocrystallography techniques. Incorporation of hexylene glycol into solution has been known to improve the resolution of X-ray diffraction making protein structures easily identifiable. Additionally hexylene glycol is not a strong denaturing agent and thus does not significantly alter the structure of a protein during the crystallography procedure. Hexylene glycol is also used as a lubricant for polishing specimens in

metallography Metallography is the study of the physical structure and components of metals, by using microscopy. Ceramic and polymeric materials may also be prepared using metallographic techniques, hence the terms ceramography, plastography and, collecti ...

. Like related diols, it forms

borate ester In organic chemistry, borate esters are organoboron compounds which are conveniently prepared by the stoichiometric condensation reaction of boric acid with alcohols. There are two main classes of borate esters: orthoborates, and metaborates, ...

References

{{DEFAULTSORT:Methyl-2, 4-pentanediol, 2- Alkanediols