p-nitrophenyl dihydrogen phosphate, compound with 2-amino-2-(hydroxymethyl)propane-1,3-diol (1:2)

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source substances and the target substance have similar partition coefficients because the source substances, Tris and 4NPP, are the only components of the target substance 4-NPP, di-TRIS. It is assumed that the partition coefficient of the target substance 4-NPP, di-TRIS is determined by its components, Tris and 4NPP.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURIT IES)
Source Substance 1
Trometamol, Tris
EC number: 201-064-4 | CAS number: 77-86-1

Source Substance 2
Disodium 4-nitrophenyl phosphate, 4NPP
EC number: 224-246-5 | CAS number: 4264-83-9

Target substance:
4-NPP, di -TRIS (4-nitrophenoxy)phosphonic acid; bis(2-amino-2-(hydroxymethyl)propane-1,3-diol)
EC number 269-198-6 | CAS number: 68189-42-4

3. ANALOGUE APPROACH JUSTIFICATION
The read-across hypothesis and justification establish the structural similarities and differences of the source and target substances. The similarities in their structures and properties serve as the foundation for this read-across and justify prediction of 4-NPP, di-TRIS's partition coefficient from Tris and 4NPP. The detailed justification for the analogue approach is added to section 13 of this dossier.
4. DATA MATRIX
The detailed data matrix for the analogue approach is added to section 13 of this dossier.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Type:

log Pow

Partition coefficient:

< -2.16

Temp.:

22 °C

pH:

6.7

Conclusions:

For both components of the substance 4-NPP, di-Tris (CAS number 68189-42-4), 4NPP (CAS 4264-83-9) and Tris (CAS 77-86-1), there are reliable data available. In aqueous solutions, the substance 4-NPP, di-TRIS, which is an organic salt, will readily dissociate into the ions Tris and 4NPP. For both substances, Tris and 4NPP, the measured log Pow is -2.31 and <-2.16, respectively. Consequently, it can be assumed that also the substance 4-NPP, di-Tris (CAS number 68189-42-4) will have a log Pow of at least <-2.16.

Executive summary:

For both components of the substance 4-NPP, di-Tris (CAS number 68189-42-4), 4NPP (CAS 4264-83-9) and Tris (CAS 77-86-1), there are reliable data available. In aqueous solutions, the substance 4-NPP, di-TRIS, which is an organic salt, will readily dissociate into the ions Tris and 4NPP. For both substances, Tris and 4NPP, the measured log Pow is -2.31 and <-2.16, respectively. Consequently, it can be assumed that also the substance 4-NPP, di-Tris (CAS number 68189-42-4) will have a log Pow of at least <-2.16.

Description of key information

No study with 4-NPP, di -TRIS (CAS 68189-42-4) is available to draw a conclusion on its partition coefficient.

Data from the analogues Tris (CAS 77-86-1) and 4-Nitrophenyl phosphate (4NPP, CAS 4264-83-9) was used on a read-across approach to fulfil this endpoint information requirement (See Read Across justification in Chapter 13).

For the components of the substance 4-NPP, di -TRIS (CAS 68189-42-4), 4-Nitrophenyl phosphate (4NPP, CAS 4264-83-9) and Tris (CAS 77-86-1), there are reliable data available. 

The partition coefficient of Tris (trometamol, CAS no. 77-86-1) was assessed in a study according to TG OECD 107. The measured logPow is -2.31. 

The log P_OW of 4-Nitrophenyl phosphate disodium salt (CAS no. 4264-83-9) was determined according to TG OECD 107. The determined log P_OW value at pH 6.7 is <-2.16 with a standard deviation of ± 0.001.

Consequently, it can be assumed that also the substance 4-NPP, di-Tris (CAS number 68189-42-4) will have a log Pow of at least <-2.16.

Key value for chemical safety assessment

Log Kow (Log Pow):

-2.16

at the temperature of:

22 °C