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Diss Factsheets

Administrative data

Link to relevant study record(s)

Description of key information

From a toxicokinetic study performed with a structural analogue (Phosphoric acid, 2-Ethylhexyl ester) it appears that Phosphoric acid, esters are efficiently absorbed, metabolised and excreted quantitatively by the body. Hydrolysis of the ester linkage  provides an adequate degradation mechanism. There was no sign of accumulation.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

Assessment of the Toxicokinetic Behaviour


Phosphoric acid, butyl ester (CAS-No. 12788-93-1)


There are no studies available in which the toxicokinetic properties of Phosphoric acid, butyl ester were investigated.


Phosphoric acid, butyl ester,a clear viscous liquid, is a multiconstituent substance.Based on the two tests the water solubility is depending on the on the mono-/diester ratio of this substance. The lowest value of 61 g/L is used for the chemical safety assessment (see chapter 4.8). The octanol water partition coefficient (Log Pow) value was determined to be -0.4 (see chapter 4.7). Due to the relative low Log Powof -0.4 in combination with the high water solubility and the assumed hydrolysis of the ester binding to form phosphoric acid and the alcohol components (see chapter 7.1.1) no potential of bioaccumulation is assumed.



With reference to its physical state (liquid), the Log Powof -0.4, and the relatively high water solubility the absorption of Phosphoric acid, butyl ester might be assumed to take place in considerable amounts. In addition a passage through aqueous pores is possible (please refer to Guidance on information requirements and chemical assessment, Chapter R.7c, Table R.7.12-1, p. 152). On the other site, the substance contains several hydroxyl functions which might be ionisable. Ionisation does not contribute to a ready diffusion across biological membranes (please refer to Guidance on information requirements and chemical assessment, Chapter R.7c, p. 150). Therefore, excessive-scale absorption of Phosphoric acid, butyl ester might be excluded. This assumption is strengthened by the results of the acute oral toxicity studies in rats (LD502474 mg/kg bw) that indicate a low acute toxicity.



Phosphoric acid, butyl esteris a veryhydrophilic substance that contains relatively small molecular components. Therefore, it will be distributed widely and tend to migrate via aqueous channels and pores (please refer to Guidance on information requirements and chemical assessment, Chapter R.7c, pp. 159-160).



Anavailable toxicokinetic study performed with Phosphoric acid, 2-ethylhexyl ester (please refer to Chapter 7.1.1) resulted a complete hydrolysis of the ester and the subsequent excretion via urine. The characteristic and functional active center of both substances (Phosphoric acid, 2-ethylhexyl ester andPhosphoric acid, butyl ester) is the ester binding between the alcoholic compound and Phosphate.With reference to the occurrence of endogenous esterases which take part in the mammalian phase I metabolism it can be assumed that both Phosphoric acid ester types are hydrolysed independent from the constitution of the alcoholic part. Studies on genotoxicity performed with Phosphoric acid, butyl ester (Ames-Test; Chromosome aberration test and an in vivo Micronucleus test in mice) were negative, i.e. there is no indication of a reactivity of the substance under the test conditions.


With reference to the lowLog Pow, the good water solubility and the molecular weight the urinary excretion is considered to be the most favorable excretion route (please refer to Guidance on information requirements and chemical assessment, Chapter R.7c, p. 162).