Ethanol, 2-methoxy-, manufacture of, by-products from, esters with boric acid

Partition coefficient

Description of key information

log Kow  of main components/hydrolysis products: < 1 at 20°C

Key value for chemical safety assessment

Log Kow (Log Pow):

1

at the temperature of:

20 °C

Additional information

For the evaluation of the log Pow experimental data and QSAR analysis are available:

Experimental evidence:

In an experimental study with a B-TTEGME containing Brake Fluid it was demonstrated that B-TT EGME has a very low potential to accumulate in organic matrices. In this GLP compliant experimental study with Brake Fluid DOT 4, containing 35% B-TTEGME, the log Pow of the constituents of the brake fluid were determined. none of the major components of the Brake fluid had a log Pow of higher than 0.5.

QSAR analysis:

This finding was supported by QSAR analysis. Since B-TTEGME is a mixture, it is not possible to perform one QSAR analysis for B-TTEGME alone. Instead, representative constituents of B-TTEGME, i.e., B-TEGME, B-TetraEGME and B-PentaEGME were analysed.

B-TTEGME is mixture of different borated glycol esters. The length of the glycol ester moiety ranges from 3 to 5 glycols per glycol ester moiety. About 50 % of B-TTEGME have a chain length of 3 glycols per glycol ester moiety. The molecule with the chain length of 3 glycol esters is registered under the name B-TEGME (cas# 30989 -05 -0). The molecule with the chain length of 4 glycol esters (B-TetraEGME) has the cas 57057 -98 -4. The molecule with a chain length of 5 has the cas # 75672 -72 -9. B-TEGME and B-PentaEGME represents the extremes for the glycol ester chain length of B-TTEGME. Hence, they can be considered to be representative for the risk assessment. The QSARs for the log Pow were performed using the software EPIWIN40 with the kowwin module (version 1.67). This QSAR software is recommended in the "Guidance on information requirements and chemical safety assessment Chapter R.7a: Endpoint specific guidance", Section R.7.1.8 page 103. The kowwin module calculates the log Pow based on the fragment addition method.

Results of the QSAR analysis:

The Epiwin kowwin (version 1.67) calculation resulted in a log Pow of -4.37 for B-TEGME, -5.19 for B-TetraEGME and -6.01 for B-PentaEGME.

Impact of the glycol ester moieties:

QSARs were performed for glycol esters with chain lengths of 3 (B-TEGME), 4 (B-TetraEGME) and 5 (B-PentaEGME), resulting in log Pows of -4.37, -5.19, and -6.01, respectively. Based on this trend of decreasing log Pow with increasing chain length, the log Pow value obtained for B-TEGME must be considered to be a worst case for B-TTEGME (B-TEGME is the smallest molecule in B-TTEGME). The log Pow of B-TEGME of -4.37 indicates a low risk for bioaccumulation.

Summary and Conclusion for B-TTEGME:

Based on the experimental finding and the QSAR analysis, the log Pow of B-TTEGME is clearly below 1. The risk assessment will be made with a log Pow of 1 which must be considered as worst case scenario of a B-TTEGME.

Both the experimental study and the QSAR indicate that a log Pow of 1 represents a worst case scenario. This value will be used for the risk assessment of B-TTEGME.