N-[3-({[2,2-dimethyl-3-(morpholin-4-yl)propylidene]amino}methyl)-3,5,5-trimethylcyclohexyl]-2,2-dimethyl-3-(morpholin-4-yl)propan-1-imine

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2014-07-03 to 2014-07-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Version / remarks:

adopted 13 April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - HPLC Method)

Version / remarks:

dated 31 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

2.1

Temp.:

25 °C

pH:

>= 6 - <= 7

Details on results:

Additional experiment was performed with the hydrolysis product - Aldehyd M. The samples of Aldehyd M and the test item were analysed by HPLC under the same conditions. The retention times and the profile of chromatograms are the same, therefore the evaluated peak of the test item and the results of the logPow refers to hydrolysis product Aldehyde M (2,2-Dimethyl-3-(4-morpho-linyl)propanal).

Table 2.:          Measured and calculated data of the reference substances
Chemical name	log Pow OECD 117	Retention time (min)	log k Calculated	Repeatability DlogPow log unit		Accuracy log unit		log Pow Calculated
Thiourea	-	2.90	-
		2.90
		2.90
		2.90
		2.90
		2.90
	Mean	2.90
	CV%	0.00
2-Butanone	0.3	3.66	-0.582		0.01		0.19		0.5
		3.66	-0.582						0.5
		3.65	-0.587						0.5
		3.65	-0.587						0.5
		3.65	-0.587						0.5
		3.66	-0.582						0.5
	Mean	3.66	-0.584						0.5
	CV%	0.1	-						-
Acetanilide	1.0	4.05	-0.401		0.02		0.06		0.9
		4.06	-0.398						1.0
		4.04	-0.405						0.9
		4.04	-0.405						0.9
		4.05	-0.402						0.9
		4.05	-0.402						0.9
	Mean	4.05	-0.402						0.9
	CV%	0.2	-						-
Benzonitrile	1.6	4.61	-0.229		0.01		0.24		1.4
		4.61	-0.229						1.4
		4.60	-0.232						1.4
		4.60	-0.232						1.4
		4.61	-0.229						1.4
		4.61	-0.229						1.4
	Mean	4.61	-0.230						1.4
	CV%	0.1	-						-
Acetophenone	1.7	5.04	-0.132		0.01		0.10		1.6
		5.03	-0.134						1.6
		5.02	-0.136						1.6
		5.02	-0.136						1.6
		5.03	-0.134						1.6
		5.03	-0.134						1.6
	Mean	5.03	-0.134						1.6
	CV%	0.1	-						-
Methyl Benzoate	2.1	6.89	0.139		0.01		0.16		2.3
		6.89	0.139						2.3
		6.88	0.137						2.3
		6.87	0.136						2.3
		6.89	0.139						2.3
		6.89	0.139						2.3
	Mean	6.89	0.138						2.3
	CV%	0.1	-						-
Ethyl Benzoate	2.6	9.40	0.351		0.01		0.18		2.8
		9.41	0.351						2.8
		9.38	0.349						2.8
		9.38	0.349						2.8
		9.42	0.352						2.8
		9.42	0.352						2.8
	Mean	9.40	0.351						2.8
	CV%	0.2	-						-
Benzophenone	3.2	10.77	0.434		0.01		0.22		3.0
		10.76	0.433						3.0
		10.74	0.432						3.0
		10.74	0.432						3.0
		10.77	0.434						3.0
		10.78	0.434						3.0
	Mean	10.76	0.433						3.0
	CV%	0.2	-						-
Diphenylamine	3.4	13.56	0.565		0.00		0.09		3.3
		13.56	0.565						3.3
		13.54	0.565						3.3
		13.54	0.565						3.3
		13.58	0.566						3.3
		13.59	0.567						3.3
	Mean	13.56	0.565						3.3
	CV%	0.2	-						-
Naphthalene	3.6	16.04	0.656		0.01		0.07		3.5
		16.03	0.656						3.5
		16.06	0.657						3.5
		16.06	0.657						3.5
		16.13	0.659						3.5
		16.14	0.659						3.5
	Mean	16.08	0.657						3.5
	CV%	0.3	-						-
Biphenyl	4.0	26.27	0.906		0.01		0.15		4.1
		26.27	0.906						4.1
		26.32	0.907						4.1
		26.31	0.907						4.1
		26.46	0.910						4.2
		26.44	0.909						4.2
	Mean	26.35	0.908						4.1
	CV%	0.3	-						-
Phenanthrene	4.5	-*	-		0.00		0.09		-
		-*	-						-
		38.36	1.087						4.6
		38.37	1.087						4.6
		38.49	1.089						4.6
		38.46	1.089						4.6
	Mean	38.42	1.088						4.6
	CV%	0.2	-						-

Table 3.: Measured and calculated data of SIKA Hardener MI (SIKA Härter MI)
Test Item name	Retention time (min)	log k	log Pow	Pow	Repeatability log unit
		Calculated
test item prepared in eluent	-*	-	-	-	0.02
	6.33	0.073	2.10	127
	6.36	0.077	2.11	130
	6.33	0.073	2.10	127
	6.33	0.073	2.10	127
	6.31	0.070	2.10	125
test item prepared in acetonitrile	6.32	0.072	2.10	126
	6.34	0.074	2.11	128
Mean	6.33	0.073	2.10	127	-
Conf.int.(95%)	0.015	-	0.005	1.3	-
CV%	0.2	-	-	-	-

The retention times and the profile of chromatograms are the same, therefore the evaluated peak of the test item and the results of the log Pow refers to hydrolysis product Aldehyde M (2,2-Dimethyl-3-(4-morpho-linyl)propanal).

Conclusions:

Due to fast hydrolysis it was technically not possible to determine the partition coefficient log Pow of the parent test substance. Nevertheless the log Pow of the hydrolysis product was determined to be log Pow = 2.1 ± 0.005.

Executive summary:

A study was conducted in accordance with OECD TG 117 and Regulation (EC) No 440/2008 method A.8 to determine the partition coefficient of the test item. The test item consists of two imine groups which are known to be hydrolytically unstable. Therefore it was assumed that under the test conditions the substance will undergo hydrolysis forming the respective aldehyde and amine compounds. The hydrolysis products were determined to be aldehyde 2,2-dimethyl-3-(morpholin-4-yl)propanal (Aldehyde M) and amine 3-aminomethyl-3,5,5-trimethylcyclohexylamine (Isophorondiamine; IPDA) (please refer to IUCLID section 5.1.2). Using the HPLC method the partition coefficient (Pow) was determined in three independent measurements. Taken the initial assumption into account two stock solutions of the test substance and the hydrolysis product aldehyde M were prepared in acetonitrile. These stock solutions were diluted in the mobile phase (70 % methanol and 30 % water (v/v) resulting in concentrations of the test solutions of approximately 50 µg/mL. The resulting solution was directly measured via HPLC-UV at 25 ± 1 °C.

The reference item mix was analysed in six independent measurements and the test substance in three measurements, respectively. For each reference item, the capacity factor K was calculated from the retention time of thiourea and the retention time of the respective reference items. A calibration function (log K versus log Pow, linear fit) was determined using the literature values for Pow of the reference items and the retention times in the six determinations. The coefficient of determination r2 of the calibration function log K/Log Pow was calculated. According to the guideline criteria this value was considered as sufficient to use the calibration function for the determination of the log Pow of the test item. The retention times and the profile of chromatograms are the same for the test item itself and the hydrolysis product aldehyde M. Therefore it was concluded that under the test condition the test item undergoes hydrolysis. Thus, the log Pow of the parent substance could not be determined. The evaluated peak of the test item and the results of the log Pow refers to hydrolysis product aldehyde M (2,2-Dimethyl-3-(4-morpho-linyl)propanal).The log Pow was determined to be 2.10 ± 0.005 at 25 °C.

Description of key information

The substance hydrolysis fast in contact with water, thus it was technically not feasible to perform the study with the present substance. Instead the log Pow of the hydrolysis product was determined to be 2.1 at 25 °C.

Key value for chemical safety assessment

Log Kow (Log Pow):

2.1

at the temperature of:

25 °C

Additional information

Hydrolysis

The substance consists of two imine groups which are known to be hydrolytically unstable. The substance will undergo hydrolysis forming the respective aldehyde and amine compounds (please refer to IUCLID section 5.1.2). The test item rapidly decomposes in contact with water under formation of the respective aldehyde 2,2-dimethyl-3-(morpholin-4-yl)propanal (Aldehyde M) and amine 3-aminomethyl-3,5,5-trimethylcyclohexylamine (Isophorondiamine; IPDA). Thus, for the environmental risk assessment log Pow of the substance itself and the hydrolysis product were evaluated.

 

Key study for the test item and the hydrolysis product aldehyde M

A study was conducted in accordance with OECD TG 117 and Regulation (EC) No 440/2008 method A.8 to determine the partition coefficient of the test item. The test item consists of two imine groups which are known to be hydrolytically unstable. Therefore it was assumed that under the test conditions the substance will undergo hydrolysis forming the respective aldehyde and amine compounds. The hydrolysis products were determined to be aldehyde 2,2-dimethyl-3-(morpholin-4-yl)propanal (Aldehyde M) and amine 3-aminomethyl-3,5,5-trimethylcyclohexylamine (Isophorondiamine; IPDA) (please refer to IUCLID section 5.1.2). Using the HPLC method the partition coefficient (Pow) was determined in three independent measurements. Taken the initial assumption into account two stock solutions of the test substance and the hydrolysis product aldehyde M were prepared in acetonitrile. These stock solutions were diluted in the mobile phase (70 % methanol and 30 % water (v/v) resulting in concentrations of the test solutions of approximately 50 µg/mL. The resulting solution was directly measured via HPLC-UV at 25 ± 1 °C.

The reference item mix was analysed in six independent measurements and the test substance in three measurements, respectively. For each reference item, the capacity factor K was calculated from the retention time of thiourea and the retention time of the respective reference items. A calibration function (log K versus log Pow, linear fit) was determined using the literature values for Pow of the reference items and the retention times in the six determinations. The coefficient of determination r2 of the calibration function log K/Log Pow was calculated. According to the guideline criteria this value was considered as sufficient to use the calibration function for the determination of the log Pow of the test item. The retention times and the profile of chromatograms are the same for the test item itself and the hydrolysis product aldehyde M. Therefore it was concluded that under the test condition the test item undergoes hydrolysis. Thus, the log Pow of the parent substance could not be determined. The evaluated peak of the test item and the results of the log Pow refers to hydrolysis product aldehyde M (2,2-Dimethyl-3-(4-morpho-linyl)propanal).The log Pow was determined to be 2.10 ± 0.005 at 25 °C.

 

Supporting study for the Hydrolysis product 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophoron diamine; IPDA)

Two different study data for the hydrolysis product IPDA were available (Please refer to disseminated ECHA dossier CAS 2855-13-2).

 

In a supporting study the partition coefficient 1-octanol/water of isophorone diamine was determined according to OECD TG 107 (1995) and EC Method A.8 (1992) with the shake-flask method. The result was log Kow = 0.99 (Kow = 9.8) at 23 °C (pH 6.34 for water phase without test substance).

 

In a second supporting study the partition coefficient 1-octanol/water of isophorone diamine was determined according to OECD TG 107 (1981) with the shake-flask method. The result was log Kow = 0.79 at 23 °C. Experimental details have not been reported.

 

In conclusion, the reported study results were in the same range and were therefore regarded as reliable. A log Pow of 0.99 was regarded as worst case assumption.

 

Conclusion

Based on the results of the hydrolysis study it was concluded, that when getting into contact with water the substance undergoes fast hydrolysis. Thus, a experimental determination of the log Pow of the parent compound is technically not possible. Instead the log Pow of the respective aldehyde was determined to be 2.1 at 25 °C and the log Pow of the respective imine was determined to be 0.99.

For chemical hazard and exposure assessment the highest (worst case) log Pow of the hydrolysis products (2.1 from Aldehyde M) was used.