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Environmental fate & pathways

Hydrolysis

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Description of key information

The hydrolysis of SIKA Hardener MH in different media (ultra-pure water, aprotic and protic organic solvents like acetonitrile and methanol)  and the stability of SIKA Hardener MH's degradation product (Aldehyde M) in water and aqueous buffer solutions (OECD and ISO medium) at room temperature were investigated using LC/MS and LC/MS/MS, respectively. 
Measurements revealed a very fast hydrolysis of SIKA Hardener MH in water and water-based media (t1/2 < 0.6 minutes in water). The degradation products of the hydrolysis of SIKA Hardener MH are 2,2-dimethyl-3-(morpholin-4-yl)propanal (Aldehyde M) and hexanediamine.

Key value for chemical safety assessment

Half-life for hydrolysis:
0.6 min
at the temperature of:
25 °C

Additional information

The hydrolysis of SIKA Hardener MH and the identifiaction of the decomposition products was assessed in a way similar to the methods described in OECD guideline no. 111 and EU method C.7.

The hydrolysis of SIKA Hardener MH in different media (water, aprotic and protic organic solvents like acetonitrile and methanol) and the stability of the degradation product (2,2-dimethyl-3-(morpholin-4-yl)propanal (Aldehyde M)) in water and aqueous buffer solutions (OECD and ISO medium) at room temperature was investigated using LC/MS.

Measurements revealed a very fast hydrolysis of SIKA Hardener MH in water and water-based media (t1/2 < 0.6 minutes in water). The degradation products of the hydrolysis of SIKA Hardener MH 2,2-dimethyl-3-(morpholin-4-yl)propanal (Aldehyde M) and hexanediamine were successfully identified via their MS signals. In the aprotic organic solvent acetonitrile SIKA Hardener MH is stable for at least 26 hours storage. In contrast in the protic solvent methanol SIKA Hardener MH is not stable.

The storage stability of the degradation product of SIKA Hardener MH (Aldehyde M) was evaluated in aqueous solutions (ultra-pure water, OECD and ISO medium). In ultra-pure water Aldehyde M is stable for at least 26 hours. In aqueous buffer solutions (OECD and ISO medium) a rapidly decreasing signal of Aldehyde M was observed. In OECD medium approximately 5 times and in ISO medium approximately 1.5 times lower Aldehyde M concentration were measured after 26 hours. This observation indiactes that the measured concentration of Aldehyde M in these ecotoxicological media does not reflect its real concentration.