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Environmental fate & pathways

Hydrolysis

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Description of key information

The hydrolysis of the test item (1,6-hexanediyl-bis(2-[2-{1-ethylpentyl}-3-oxazolidinyl]ethyl) carbamate) was investigated using HPLC-MS and GC-MS. Measurements revealed a fast hydrolysis of the test item. The hydrolysis degradation products of the test item were identified qualitatively. The first hydrolysis product was determined to be 2-ethylhexanal. The second hydrolysis degradation product was identified on the basis of its molecular weight. The second, more likely hydrolysis product, which is in good consistency with the experimentylly determined molecular weight, is 1,6 hexanediyl-bis-carbamic acid bis(N-hydroxyethyl-2-aminoethyl) ester.

Key value for chemical safety assessment

Additional information

The hydrolysis of the test item (1,6-hexanediyl-bis(2-[2-{1-ethylpentyl}-3-oxazolidinyl]ethyl) carbamate) and the identifiaction of the decomposition products were assessed in accordance with the OECD guideline 111 and the EU method C.7.

The test item immediately hydrolysed in water and the formed hydrolysis products are partly insoluble in water as well. To investigate the hydrolysis process a stock solution of the test item in acetonitrile was prepared. This solution was added to a mixture of acetonitrile / water (1/1) and to water resulting in test mixtures of 0.8 mmol/L test item in acetonitrile / water (1/1) and in water. The acetonitrile / water mixture was investigated by HPLC-MS and it’s diethylether extract was investigated by GC-MS.

After adding the acetonitrile stock solution to water, an immediate precipitation was observed. An organic extract of the mixture was investigated by GC-MS and the aqueous phase was investigated by HPLC-MS. By GC-MS analysis of both extracts only one signal was detected, identified by comparison with the Wiley 275.L mass spectra data base as 2-Ethyl-hexanale, the first hydrolysis product. The HPLC-MS analysis of both aqueous mixtures showed two signals, one of the minor component 2-(1-Ethylpentyl)-3-(2-hydroxyethyl)-oxazolidine and of the hydrolysis product 1,6 hexanediyl-bis-carbamic acid bis(N-hydroxyethyl-2-aminoethyl) ester. The 2 -ethylhexanal is insoluble in water and forms droplets at the flask walls. It is soluble inorganic medium (diethylether and acetonitrile) and was therefore detected by GC-MS. Hydrolysis takes place immediately after contact with water. No test item 1,6-hexanediyl-bis(2-[2-{1-ethylpentyl}-3-oxazolidinyl]ethyl) carbamate could be detected.

Additional remark:

In the course of the GC-MS analysis in the present hydrolysis study the first hydrolysis product was clearly identified as 2-ethyl-hexanale. The other, second hydrolysis product was detected using HPLC-MS. For the second hydrolysis product the molecular weight (Mw) was reported to be 378 g/mol. However, the postulated hydrolysis reaction considering these hydrolysis products seems to be not correct, e.g. in particular regarding the completeness and the mass balance in chemical reactions, i.e. the postulated chemical structure of the second hydrolysis product is not consistent with the experimentally determined molecular weight (378 g/mol). Thus, considering 2-ethyl-hexanale as one of the hydrolysis degradation product, the other hydrolysis degradation product, which is more likely, is 1,6 hexanediyl-bis-carbamic acid bis(N-hydroxyethyl-2-aminoethyl) ester with a calculated molecular weight of 376.5 g/mol.

Considering the results form a hydrolysis study (supporting study) with the analogue substance (bis[2-[2-(2-(1-methylethyl)-3-oxazolidinyl]ethyl] hexane-1,2-diylbiscarbamate) the second, more likely hydrolysis product which is formed in the course of the hydrolysis of 1,6-hexanediyl-bis(2-[2-{1-ethylpentyl}-3-oxazolidinyl]ethyl) carbamate is 1,6 hexanediyl-bis-carbamic acid bis(N-hydroxyethyl-2-aminoethyl) ester. This further confirms the assumption above.