N,N,N',N'-tetramethylhexamethylenediamine

PBT assessment

PBT assessment: overall result

Reference

Name:

N,N,N',N'-tetramethylhexane-1,6-diamine

Type of composition:

boundary composition of the substance

State / form:

liquid

Reference substance:

N,N,N',N'-tetramethylhexane-1,6-diamine

PBT status:

the substance is not PBT / vPvB

Justification:

PBT / vPvB - Assessment for the parent compound N,N,N',N'-tetramethylhexane-1,6-diamine (CAS 111-18-2):

Based on an enhanced OECD 301 B test, N,N,N',N'-tetramethylhexane-1,6-diamine (CAS 111-18-2) is not readily, but inherently biodegradable with a degradation of 87% after 60 days (56% after 32 days; BASF SE 2012, report no. 22G0487/11G091). Therefore, N,N,N',N'-tetramethylhexane-1,6-diamine should be assessed P from a precautionary point of view. The log Kow (1.99, measured, BASF SE 2013, report no. 11L00324) as well as several QSAR calculations (calculated BCF values range between 2.45 L/kg and 39.6 L/kg, BASF SE 2016, 2020) indicate no potential for bioaccumulation (not B/vB). The substance is not toxic (not T) since the lowest EC10 is > 0.01 mg/L (daphnids, 21-d EC10 reproduction = 0.86 mg/L, BASF SE 2013, report no. 51E0487/11E119) and it holds no relevant classification.

In conclusion, the substance is considered to be not PBT / not vPvB.

 

PBT / vPvB - Assessment for modelled metabolites of N,N,N',N'-tetramethylhexane-1,6-diamine (CAS 111-18-2):

ECHA Guidance on information requirements and chemical safety assessment (v3.0, June 2017), Chapter R.11.4.1 specifies that “Constituents, impurities and additives should normally be considered relevant for the PBT/vPvB assessment when they are present in concentration of ≥ 0.1% (w/w)” […] “Similar arguments apply to relevant transformation/degradation products”.

In order to identify the relevant degradation products of N,N,N',N'-tetramethylhexane-1,6-diamine a standard information requirement according to Column 1, Section 9.2.3. of Annex IX to REACH and for purposes of an assessment of potential PBT/vPvB properties, the metabolites were modelled using CATALOGIC 301C v11.15 – July 2018 as well as BCF base-line v03.10 – July 2018 (OASIS CATALOGIC v5.13.1.156).

Overall, the model CATALOGIC 301C v11.15 calculated 29 metabolites (Table 1) identifying 16 metabolites as relevant degradation products in terms of PBT/vPvB assessment, with an estimated quantity of ≥0.1% (equivalent to quantity setting in OASIS CATALOGIC: 0.001-2 [mol/mol parent]).

Table 1: QSAR prediction for CAS 111-18-2 using CATALOGIC 301C v11.15 – July 2018 (OASIS CATALOGIC v5.13.1.156;metabolites with a quantity > 0.001 mol/mol parent (approx. 0.1%) after 28 d are highlighted by grey background and bold type; metabolite no: according to (Q)SAR model Catalogic v11.15 – July 2018 (OASIS CATALOGIC v5.13.156))

#	Metabolite (no)	SMILES	Substance name (CAS)	Quantity (mol/mol parent)	Log Kow	BOD prediction (% after 28 d)	PBT-Assessment: ECHA (disseminated substances)
parent	1	CN(C)CCCCCCN(C)C	N,N,N',N'-tetramethylhexane-1,6-diamine (CAS 111-18-2)	0.683	1.70	8	not PBT/vPvB
1	15	C=O	Formaldehyde (CAS 50-00-0)	0.0063	0.35	100	not PBT/vPvB
2	2	CNCCCCCCN(C)C	1,6-Hexanediamine, N,N,N'-trimethyl- (CAS 1862-11-9)	0.0266	1.49	36	not registered under REACH
3	22	CN(C)CCCCCCN(C)CO	not identified	0.1016	0.24	8	not identified
4	16	OC=O	Formic acid (CAS 64-18-6)	3.87E-06	-0.46	100	not checked
5	14	CN	Methanamine (CAS 74-89-5)	0.0349	-0.64	64	not PBT/vPvB
6	3	CN(C)CCCCCC=O	Hexanal, 6-(dimethylamino)- (CAS 2554-94-1)	0.0035	1.00	37	not registered under REACH
7	21	CN(C)CCCCCCN	1,6-Hexanediamine, N,N'-dimethyl- (CAS 13093-04-4)	0.0326	1.02	29	not registered under REACH
8	23	CN(C)CCCCCCNCO	not identified	0.0019	0.02	36	not identified
9	25	CNCCCCCCN(C)CO	not identified	0.0019	0.02	37	not identified
10	4	CN(C)CCCCCC(O)=O	Hexanoic acid, 6-(dimethylamino)- (CAS 1072-09-9)	1.38E-06	-1.94	34	not checked
11	24	NCO	Cyanooxy (CAS 22400-26-6)	5.668E-08	-2.10	100	not checked
12	26	CN(CCCCCC=O)CO	not identified	0.0035	-0.46	39	not identified
13	33	CN(CCCCCCN)CO	not identified	0.0021	-0.44	30	not identified
14	5	CN(C)CCCC=CC(O)=O	not identified	1.38E-06	-0.66	34	not checked
15	27	CN(CCCCCC(O)=O)CO	not identified	5.667E-08	-3.41	36	not checked
16	6	CN(C)CCCC(O)CC(O)=O	not identified	1.38E-06	-3.48	31	not checked
17	28	CN(CCCC=CC(O)=O)CO	not identified	5.667E-08	-2.12	36	not checked
18	7	CN(C)CCCC(=O)CC(O)=O	not identified	1.38E-06	-3.99	31	not checked
19	29	CN(CCCC(O)CC(O)=O)CO	not identified	5.667E-08	-4.54	33	not checked
20	8	CN(C)CCCC(O)=O	Butanoic acid, 4-(dimethylamino)- (CAS 693-11-8)	0.1226	-2.92	8	not registered under REACH
21	20	CC(O)=O	Acetic acid (CAS 64-19-7)	1.43E-06	0.09	100	not checked
22	30	CN(CCCC(=O)CC(O)=O)CO	not identified	5.667E-08	-5.46	33	not checked
23	9	CNCCCC(O)=O	Butanoic acid, 4-(methylamino)- (CAS 1119-48-8)	0.0026	-3.14	66	not registered under REACH
24	31	CN(CCCC(O)=O)CO	not identified	0.0051	-4.39	9	not identified
25	10	OC(=O)CCC=O	Butanoic acid, 4-oxo- (CAS 692-29-5)	0.0015	-0.42	91	not registered under REACH
26	19	NCCCC(O)=O	2-Butynoic acid, 4-amino- (CAS 56-12-2)	0.0023	-3.60	57	not PBT/vPvB
27	32	OCNCCCC(O)=O	not identified	6.18E-04	-4.60	68	not checked
28	11	OC(=O)CCC(O)=O	Butanedioic acid (CAS 110-15-6)	8.80E-04	-0.75	90	not checked
29	12	CCC(O)=O	Propanoic acid (CAS 79-09-4)	0.0077	0.58	100	not PBT/vPvB

Persistence (“P/vP”):

In order to assess the biodegradation potential of the relevant degradation products, the (Q)SAR model CATALOGIC 301C v11.15 – July 2018 (OASIS CATALOGIC v5.13.1.156) was applied.    

Concerning the applicability domain (OECD Principle 3) N,N,N',N'-tetramethylhexane-1,6-diamine is in the parametric, the structural and the metabolic domain (100%).

- The model was used to predict potential metabolites.

- 11 of the 16 metabolites identified as relevant degradation products were calculated to be not readily biodegradable (threshold value: <60% BOD). Individual biodegradation of these metabolites was estimated to be in a range of 8% to 57% after 28 days (based on BOD).

- The remaining five relevant metabolites were estimated to be readily biodegradable (5 of 16; threshold value: ≥60%), with individually calculated biodegradation values between 64% and 100% after 28 days (based on BOD).

In conclusion, 69% of the predicted metabolites present in concentration of ≥0.1% (equivalent to quantity setting in OASIS CATALOGIC: 0.001-2 [mol/mol parent]) are estimated to be not readily biodegradable while 31% of the relevant metabolites are predicted to be readily biodegradable.

The eleven degradation products of N,N,N',N'-tetramethylhexane-1,6-diamine (CAS 111-18-2) which are predicted as not readily biodegradable metabolites should be considered as potentially P/vP from a precautionary point of view, until further data become available.

Bioaccumulation (“B/vB”):

Referring to uncharged molecules, the estimation model CATALOGIC 301C v11.15 – July 2018 (OASIS CATALOGIC v5.13.1.156) calculated for the parent compound N,N,N',N'-tetramethylhexane-1,6-diamine (CAS 111-18-2) a log Kow of 1.70, while in a test according to OECD 107 a log Kow of 1.99 at 23 °C was measured (BASF SE, 2013, report no.: 11L00324, see IUCLID Ch. 4.7). Both values indicate low potential for bioaccumulation.

Without exception, all the 29 modelled degradation products of N,N,N',N'-tetramethylhexane-1,6-diamine were estimated to exhibit log Kow values of clearly < 4.5 (see Table 1), thereby not fulfilling the screening criteria for bioaccumulation (B/vB) as laid down in Section 3.1 of REACH Annex XIII.

Based on the estimation data available for the modelled metabolites, all relevant metabolites of N,N,N',N'-tetramethylhexane-1,6-diamine are concluded to be “not B” and “not vB”.

 

Toxicity (“T”):

Considering potential “T” properties, limited data are available for the relevant metabolites of the parent compound N,N,N',N'-tetramethylhexane-1,6-diamine. Only few of the relevant metabolites of both CATALOGIC models are registered under REACH. None of these substances were assessed to fulfill the criteria for “T”. Based on the available data on the persistence and bioaccumulation potential of all of the relevant metabolites, it can be concluded that all relevant degradation products do neither fulfill the PBT criteria (not PBT) nor the vPvB criteria (not vPvB).

Overall conclusion:

1.  Sufficient test data are available to assess the PBT/vPvB properties of N,N,N',N'-tetramethylhexane-1,6-diamine.

2.  Potentially relevant degradation products were modeled using (Q)SARmodel CATALOGIC 301C v11.15 – July 2018:

2a. Based on modeled data relevant degradation products present in concentration of ≥ 0.1% (equivalent to quantity setting in OASIS CATALOGIC: 0.001-2 [mol/mol parent]) do neither fulfill the PBT criteria (not PBT) nor the vPvB criteria (not vPvB).

2b. However, 11 predicted relevant metabolites present in concentration of ≥0.1% (equivalent to quantity setting in OASIS CATALOGIC: 0.001-2 [mol/mol parent]; CATALOGIC 301C v11.15) should be considered as potentially P/vP from a precautionary point of view.