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Environmental fate & pathways

Hydrolysis

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Description of key information

B-TTEGME contains three borated glycol esters, i.e., its components belong to the same functional class and are homologues. Its major components are B-TEGME (50% of B-TTEGME) and B-tetraEGME (40% of B-TTEMGE). B-PentaEGME contributes 10% to B-TTEGME. Ester moieties are cleaved by hydrolysis. Based on the finding that spontaneous hydrolysis occurs after addition of water to B-TEGME, at buffers 1.4, 4, 7 and 9, it is assumed that the two other B-TTEGME glycol esters are similarly hydrolyzed at these conditions.. 

Key value for chemical safety assessment

Half-life for hydrolysis:
1 d
at the temperature of:
20 °C

Additional information

B-TTEGME is a mixture of three different borated glycol esters which differ solely by the length of their "-CH2 -CH2 -O-" (glycol ether) side chains (homologues). Their basic chemical structure is identical: One boric acid molecule forms an ester with three polyethylene glycol ethers of different chain length, i.e., either three, four or five glycol ether entities. The following describes the typical composition of B-TTEGME (CAS 161907-80-8):

50 % B-TEGME (CAS 30989 -05-0) – three polyethylene glycol ether moieties with 3 glycols each (CAS 112 -35 -6)

40 % B-TetraEGME (CAS 57057-98-4) – three polyethylene glycol ether moieties with 4 glycols each (CAS 237 -42 -8)

10 % B-PentaEGME (CAS 75672 -72-9) - three polyethylene glycol ether moieties with 5 glycols each (CAS 23778 -52 -1)

Abiotic breakdown of this chemical class is by hydrolytic cleavage of the ester bond. Since ester cleavage is independent from the length of the side chain, the hydrolysis of B-TEGME is relevant to describe the hydrolysis of the other two borated glycol esters of B-TTEGME.

BASF 1999a investigated the hydrolysis of B-TEGME as a function of the pH and confirms the instability of B-TEGME in the environment: B-TEGME was added to 4 buffer solutions at pH 1.4, 4, 7 and 9. The IR spectrum of the solution, taken immediately after addition of water, showed a dramatic change, when compared with the IR spectrum of the original substance. This indicates spontaneous hydrolysis of B-TEGME.

Due to the fact that B-TEGME is hydrolysed spontaneously, and since the two other components of B-TTEGME are chemical homologues (boric esters with different side chain length), it is concluded that B-TTEGME is also hydrolysed spontaneously at pH 1.4,4,7 and 9.

It should be mentioned that in accordance with EC 1907/2006, Annex VIII, point 9.2.2.1, column 2, hydrolysis as a function of the pH is not required since B-TTEGME is assumed readily biodegradable, as shown in section 4.1.2.1.2.