2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate (TMPD-MIB; trade name) is a colourless liquid with a faint odour. At room temperature and atmospheric pressure, TMPD-MIB is a liquid with an approximate melting point <-70.25 °C, a boiling point of 255-261.5 °C and a vapour pressure of 1.3 Pa.

Uses

TMPD-MIB is used as a common coalescing aid in latex paints. It could soften latex particles, allowing them to fuse to form a continuous film free from distinct physical boundaries. Despite the prevalence of TMPD-MIB in latex paints, painters and building occupants are still exposed to TMPD-MIB and its associated health effects, if any, and they are still poorly understood. Indoor measurements reported TMPD-MIB median concentrations of < 2 μg/m3 and maximum concentrations of up to 12000 μg/m3[1]. 2,2,4-Trimethyl-1,3-pentanediol monoisobutyrate is also used as an intermediate in chemical syntheses.

Toxicity

Toxicokinetics: No toxicokinetic studies of TMPD-MIB after inhalative or oral exposure are available, but it is assumed that TMPD-MIB is metabolised similarly to the related compound 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TMPD-DIB). TMPD-DIB is rapidly absorbed, metabolised and eliminated in rats. Metabolisation is predominantly by O-glucuronidation, with a lesser degree of oxidation and subsequent glucuronidation.

Acute toxicity: The acute toxicity of TMPD-MIB is low, with acute oral LD50 values in rats of 6.86 ml/kg bw. In an inhalation risk assay, six male or female rats in each dose group survived 8 hours of exposure to saturated vapours of TMPD-MIB. In animal studies, TMPD-MIB was slightly irritating to skin and eyes but did not show skin-sensitising properties.

[1] R. Corsi, Chi-Chi Lin. “Emissions of 2,2,4-Trimethyl-1,3-Pentanediol Monoisobutyrate (TMPD-MIB) from Latex Paint: A Critical Review.” Critical Reviews in Environmental Science and Technology 39 1 (2009): 1052–1080.