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EC number: 229-222-8
CAS number: 6440-58-0
It can be concluded that a study on the hydrolysis as a function of pH is not required based the rapid biodegradability of the test substance in the environment. For information, evidence of hydrolysis is included based on hydrolysis as a function of pH testing of DMDMH and its breakdown product.
Annex VIII 220.127.116.11 column 2 of the REACH Regulation, it is stated that a
study on the "Hydrolysis as function of pH" does not need to be
conducted if the “substance is readily biodegradable". As can be seen in
section 5.2, areliable
study by Mead (2001) determined that DMDMH was degraded 78% within the
10-day window and the test substance can be considered readily
studies with the degradation product showed that DMH is also readily
a study on the "Hydrolysis as function of pH" does not have to be
conducted for DMDMH.
information, data are available on hydrolysis of DMDMH. There
is also reliable hydrolysis study available for the hydrolysis product,
to the rapid hydrolysis of DMDMH to DMH studies conducted with the
hydrolysis product, DMH, are considered relevant for environmental fate
and ecotoxicology and are considered in this dossier.
& Mulee (2007) conducted a reliable (Klimisch 1) GLP compliant study
following Method C7 of Commission Directive 92/69/EEC. Samples
of DMDMH were prepared in stoppered glass flasks at nominal
concentration of 0.40 g/l in the three buffer solutions.It
was observed that the rate of hydrolysis increases with an increase in
pH. At pH 4, less than or equal to 10% hydrolysis occurred after 5 days
at 50°C, equivalent to a half-life greater than 1 year at 25°C. At pH 7,
greater than 50% hydrolysis occurred after 2.4 hours at 50°C equivalent
to a half-life less than 1 day at 25°C. At pH 9 greater than 50%
hydrolysis occurred after 2.4 hours at 50°C equivalent to a half-life
less than 1 day at 25°C. Therefore,
DT50 at pH 4 is > 1 year, at pH 7 is < 1 day, and at pH 9 is <1 day.
(2007) conducted a reliable (Klimisch 2) partially meeting the
requirements of OECD 111 method. The
objective of the study was to determine the hydrolysis of DMDMH to DMH
under simulated dirty dish washing conditions (diluted synthetic sewage
according to OECD 209) and in tap water.DMDMH
was shown to hydrolyse rapidly with half-lives < 1 h under all
conditions employed in this study. Significant differences in half-lives
at an initial DMDMH concentration of 2.5 mg/l were observed at simulated
dirty dish washing conditions (0.69 h) and in tap water (0.85 h)
respectively. No significant differences in half-lives were observed at
an initial DMDMH concentration of 10 mg/l (0.84 h at simulated dirty
dish washing conditions and 0.76 h in tap water, respectively).
& Stansbrey (1992) conducted a reliable (Klimisch 1) GLP compliant study
following U.S. EPA FIFRA N 161-1 40 CFR Sec. 158.130 methods. The
objectives of this study were to determine the effect of pH on the
hydrolysis rate constants and half-lives of 14C-DMH and characterize
major (>10% of the initial concentration of DMH) hydrolysis products of
14C-DMH. Hydrolysis half-lives of 3194 days and 1715 days were
calculated for the pH 7 (TRIS) and pH 7 (HEPES) buffer systems,
(2009) conducted a reliable (Klimisch 1) GLP compliant study following
OECD 111 methods. A significant pH-dependence of the DMDMH hydrolysis
was observed: at a temperature of 35 ± 2 °C DMDMH was shown to hydrolyze
rapidly at pH 9 with a half -life of < 1 h, moderately at pH 7 with a
half-life of 10.7 h. At pH 4 no hydrolysis was observed.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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