Dibutyl terephthalate

Water solubility

Description of key information

Key information is experimental study conducted under the most appropriate methodolgy for hydrophic compounds with densities similar to water.

Key value for chemical safety assessment

Water solubility:

0.005 mg/L

at the temperature of:

25 °C

Additional information

An OECD 105 water solubility study conducted under GLP protocols using the shake flask method resulted in a solubility value of 0.060 mg/L. Additional studies of the solubility of the test substance in algal growth medium and water used for acute aquatic effects (AAE) with fish and daphnia found the solubility to be 0.11 mg/L in AAE and <0.12 mg/L in algal growth medium. However the tests of the AAE and algal growth medium appeared to show decreasing concentrations over the duration of the test and concentration equilibrium may not have been achieved due to the short duration (24 hours) of those studies. Published studies have demonstrated that standard shake flask water solubility studies tend to overestimate the solubility of hydrophobic chemicals that exhibit densities similar to water due to the formation of emulsions or micelles. A slow-stir technique has been adopted by the OECD for octanol water partition coefficient studies (OECD 123) for these types of chemicals that alleviates this problem and provides an accurate measure of the dissolved substance in the water phase of that test. The key study for this substance's water solubility is a modification of the OECD 105 water solubility method that incorporates the slow-stir technique of the OECD 123 method. This study shows the water solubility of dibutyl terephthalate to be 4.51µg/L. While this value is one order of magnitude less than that of the shake flask supporting study, it is believed that the slow-stir method is the most accurate procedure for measuring the true dissolved concentration of these types of substances in water.