Water–Hexylene Glycol System as a Potential Medicinal Base
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PPG-75-PEG-300 Hexylene Glycol
Bährle-Rapp M. (2007) PPG-75-PEG-300 Hexylene Glycol. In: Springer Lexikon Kosmetik und Körperpflege. Springer, Berlin, Heidelberg

Use of mobile phase additives for the elution of bispecific and monoclonal antibodies from phenyl based hydrophobic interaction chromatography resins.
Hall T, Kelly GM, Emery WR.
J Chromatogr B Analyt Technol Biomed Life Sci. 2018 Oct 1;1096:20-30. doi: 10.1016/j.jchromb.2018.07.027.

Crystallization of lysozyme with (R)-, (S)- and (RS)-2-methyl-2,4-pentanediol.
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2-Methyl-2,4-pentanediol (MPD) boosts as detergent-substitute the performance of ß-barrel hybrid catalyst for phenylacetylene polymerization.
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The role of 2-methyl-2, 4-pentanediol in sodium dodecyl sulfate micelle dissociation unveiled by dynamic light scattering and molecular dynamics simulations.
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Hexylene glycol is a glycol chemical compound in which the two hydroxy groups are in the 2 and 4 positions of 2-methylpentane (isopentane).

It occurs as a colourless liquid, with a typical ammonia odour, soluble in water, ethanol and most organic solvents. 

What it is used for and where it is used

Cosmetics

The main applications of Hexylene glycol (Hexylene Glycol/2-methylpentane-2,4-diol) are mainly in cosmetics as a surfactant and low molecular weight emulsifier and to add fragrance to products.

Medicine

In pharmaceutical products it is a so-called 'intermediate product' and is included in formulas as an excipient, solvent, fragrance. It has shown better antibacterial and antifungal efficacy than propylene glycol and 1,3-butylene glycol (1).

It is a very common product and is variously employed and used as a solvent, reinforcing and bonding agent in the following products:

• lubricants and greases
• diesel and petrol antifreeze products
• adhesives and sealants
• polishes and waxes
• air care products
• washing and cleaning products
• coating products
• fillers
• fillers
• plasters
• modelling clay
• finger paints
• cosmetics and personal care products
• pH adjusters
• water treatment products
• workshop
• construction work 
• health services, scientific research and development
• textiles
• hides or fur
• chemicals

Safety

As with most chemical compounds, Hexylene glycol is no exception, albeit to a lesser extent, in cases of allergies (1).

Hexylene glycol studies

Typical optimal commercial product characteristics Hexylene glycol/2-Methyl-2,4-pentanediol

Appearance	Colorless liquid
Density	1.0±0.1 g/cm3          0.925 g/mL at 25 °C (lit.)
Boiling Point	197.5±0.0 °C at 760 mmHg
Melting Point	−40°
Flash Point	93.9±0.0°C     201 °F
Purity	≥99%
Water	≤0.5%
Acidity(mgKOH/g)	≤0.2
Vapour Pressure	0.1±0.8 mmHg at 25°C      kPa  0.006 (20°C)
Refractive Rate	n20/D1.427(lit.)
PSA	40.46000
Safety

• Molecular Formula C₆H₁₄O₂
• Linear Formula CH₃CH(OH)CH₂C(CH₃)₂OH
• Molecular Weight: 118.176 g/mol
• Exact Mass   118.099380
• UNII: KEH0A3F75J
• CAS: 107-41-5  99113-75-4
• EC Number: 203-489-0
• DSSTox Substance ID DTXSID5021885
• IUPAC  2-methylpentane-2,4-diol
• InChI=1S/C6H14O2/c1-5(7)4-6(2,3)8/h5,7-8H,4H2,1-3H3  
• InChl Key      SVTBMSDMJJWYQN-UHFFFAOYSA-N
• SMILES   CC(CC(C)(C)O)O
• PubChem Substance ID 329749326
• MDL number MFCD00004547
• Beilstein Registry Number 1098298
• ChEBI  62995
• ICSC    0660
• NSC   8098
• RTECS   SA0810000
• UN   1993
• NCI  

Synonyms: 

• 2-Methylpentane-2,4-diol
• 2-METHYL-2,4-PENTANEDIOL
• 1,1,3-trimethyl-1,3-propanediol
• (+/-)-2-Methyl-2,4-pentanediol
• 2-Methylpentan-2,4-diol
• alpha,alpha,alpha'-Trimethyltrimethylene glycol
• 1,3-dimethyl-3-hydroxybutanol
• (+-)-2-Methyl-2,4-pentanediol
• 1,3,3-trimethyl-1,3-propanediol
• 2methyl-2,4-pentanediol
• 2-methyl-2-4-pentanediol
• SCHEMBL19379
• 2,4-Pentanediol,2-methyl-
• 2-Methyl-pentane-2,4-diol
• 1,3-Trimethyltrimethylenediol
• Diolane
• Pinakon
• 2,4-Dihydroxy-2-methylpentane
• 2,4-Pentanediol, 2-methyl-
• Isol
• 4-Methyl-2,4-pentanediol
• 1,1,3-Trimethyltrimethylenediol
• 2-Methyl pentane-2,4-diol
• 2-Methyl-2,4-pentandiol

References_____________________________________________________________________

(1) Kinnunen T, Koskela M. Antibacterial and antifungal properties of propylene glycol, hexylene glycol, and 1,3-butylene glycol in vitro. Acta Derm Venereol. 1991;71(2):148-50.

(2) Spoerl D, Scherer K, Bircher AJ. Contact urticaria with systemic symptoms due to hexylene glycol in a topical corticosteroid: case report and review of hypersensitivity to glycols. Dermatology. 2010;220(3):238-42. doi: 10.1159/000275703.