2-Methyl-2,4-pentanediol (MPD) is an organic compound with the formula (CH3)2C(OH)CH2CH(OH)CH3. This colourless liquid is a chiral diol. It is produced industrially from diacetone alcohol by hydrogenation. Total European and USA production was 15000 tonnes in 2000.
2-Methyl-2,4-pentanediol exists as two enantiomers, (4R)-(-) and (4S)-(+). In the Protein Data Bank, 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, also sold as and referred to as "hexylene glycol".
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, and hydraulic fluids. 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.