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EC number: 202-112-7
CAS number: 91-97-4
Abiotic degradation / hydrolysis
Biodegradation in water: screening test
Based on the results obtained in a
biodegradation study according
to EU-method C.4–E and OECD guideline 301 D, TODI was
considered to be not readily biodegradable.The biodegradation was
followed by the oxygen uptake of the microorganisms during exposure. As
a reference item sodium benzoate was tested simultaneously under the
same conditions as the test item, and functioned as a procedure control.
Under the test conditions the percentage
biodegradation of TODI reached a mean of -4.8 % after 28 days based on
This result is supported by a study
performed with 4,4'-MDI according to OECD Guideline 302 C (Inherent
Biodegradability). Here, the average percent biodegradability of MDI and
resulting compounds in water were 0% and 6.4%, respectively.
Furthermore, the ready biodegradability of
TODI's hydrolysis product (TODA) was investigated over a period of 28
days. The biodegradation was followed by the oxygen uptake of the
microorganisms during exposure. As a reference item aniline was tested
simultaneously under the same conditions as the test item. Under the
test conditions the percentage biodegradation of TODA reached 3% based
on TOD and reached 6% by HPLC after 28 days. Therefore the test item can
be considered to be not ready biodegradable.
Biodegradation in water and sediment:
In accordance with column 2 of REACH
Regulation 1907/2006/EC Annex IX section 126.96.36.199, the study
“Biodegradation in water: simulation test” does not need to be conducted
as the test substance is highly insoluble in water. During experimental
tests organic solution was required to allow good mixing of test item
with water. Also, hydrolysis of TODI was found to be very fast.
Biodegradation in soil
Due to the fast reaction with moisture, MDI
(methylenediphenyl diisocyanate; CAS no. 26447-40-5, EC no. 247-714-0,
structural similar to TODI) isomers and polymers are assumed to form
inert, insoluble solid polyureas in soil. As MDI is structural similar
to TODI, this can also be assumed for TODI.
Bioaccumulation in aquatic species
In accordance with column 2 of REACH
1907/2006/EC Annex IX, section 9.3.2, a bioaccumulation test in aquatic
species does not need to be conducted as
- TODI was found insoluble in water (thus
uptake into biological cells is very unlikely)
- TODI did not reveal aquatic toxicity at
concentrations below water solubility
- TODI’s hydrolysis was found to be very
- TODI’s degradation product was found to be
insoluble in organic and aqueous solvents (See IUCLID sections 6.1.1,
short-term toxicity to fish and 6.1.3, short-term toxicity to aquatic
- For TODI’s degradation product TODA the
measured BCF was below 100 (0.2 mg/L: 4.8 - 34; 0.02 mg/L: 10-83) and
the estimated BCF was 16.25 L/kg wet-wt.
Thus, based on the fast hydrolysis of TODI
(The t1/2 at pH 4 and 9, at 25 and 50 °C was lower than or equal as 2
minutes; at pH7 the t1/2 was 16 hours and 1.2 hours at 25 and 50 °C
respectively.) and the low BCF value of the degradation product TODA,
bioaccumulation of the environmentally relevant degradation product TODA
is considered negligible and no further information concerning
bioconcentration or bioaccumulation for TODI is required.
accordance with column 2 of REACH Annex VIII, the test on
adsorption/desorption (required in REACH Regulation, ANNEX VIII, Section
9.3.1) does not need to be conducted if the substance and its
degradation products decompose rapidly. According to the study on
determination of the hydrolysis of TODI as a function of pH (see IUCLID
section 5.1.2), the half-life of TODI was determined to be far below 12
hours (max.: 1.2 h at pH 7) and therefore was found to be hydrolytically
due to the very low water solubility a test is technical not feasible.
to address this endpoint, estimations using KOCWIN of EPI Suite
compilation were performed for TODI and TODA (the product of hydrolysis
of TODI), resulting in Koc values of or 1.8exp5 L/kg (Kow method) or
4.2exp5 L/kg (MCI method) for TODI, and 3190 L/kg (MCI method) or 150
L/kg (Kow method) for TODA at 25°C. Based on hydrolysis data of TODI and
the calculated adsorption (to sediment and to soil) data of TODA,
adsorption can be assumed to be very low or negligible.
the Koc values of TODI's hydrolysis degradation product TODA
([1,1'-Biphenyl]-4,4'-diamine, 3,3'-dimethyl-) were estimated by
calculation to be 1, 1, 3.03, 61.9, 258, 347, 359, 361, 361 and 361 at
pH 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10, respectively (all values at 25 °C).
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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