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Description of key information

No specific study was performed to assess the hydrolysis of 1,3-diethyl-2-thiourea but it's well recognised that thioureas are stable in aqueous medium. Several read-across data have been used in order to confirm this information. 

Key value for chemical safety assessment

Additional information

Several publications from William H.R. and David G. Walker present the conclusions of kinetic studies of thiourea derivatives. These studies have been performed in aqueous media at elevated temperatures. The authors indicate that this reaction is independent on pH and give rate constants (k) obtained at various temperatures. Half-life can be estimated with the following equation: Half-life (t ½) = ln (2) / k


Following date are given for a temperature of 100°C:


-methylthiourea: the constant k is comprised between 0.65 x 10-7s and 2.09 x 10-7s.

k = 0.65 x 10-7(t ½) = 10 663 802.78 sec = 123 days

k = 2.09 x 10-7(t ½) = 3 316 493.69 sec = 38 days


-dimethylthiourea: the constant k is 2.23 x 10-7s.

(t ½) = 3 108 283.32 sec = 36 days


-sym-dimethylthiourea: the constant k is 2.5 x 10-7s.

(t ½) = 2 772 588.7 sec. = 32 days


Furthermore, considering its structure, the authors suggest that hydrolysis is unimportant. Indeed, hydrolysis of dimethythiourea should form ammonia: from pH 1 to pH 11, no ammonia was detected by their sensitive tests in reacted solutions of this compound.


This stability in aqueous medium is also mentioned in a publication from Schmidt-Bleek al.which quotes several data obtained on chemicals by "German Chemical Industry" and "highly experienced research institutes of the German federal Republic sponsored by the Umweltbundesamt".

At last, regarding the analytical monitoring performed during ecotox studies (up to 96 hours), which show that 1,3-diethyl-2-thiourea measured concentrations were maintained closed to 100% of the nominal concentrations, one can consider that hydrolysis of 1,3-diethyl-2-thiourea is unimportant.