Dodecanoic acid, 3-[[2-(2-hydroxyethoxy)ethyl]imino]-2,2-dimethylpropyl ester

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

For justification for type of information please refer to the Read-Across Justification attached to IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Transformation products:

yes

pH:

4

Temp.:

15 °C

DT50:

< 5 min

Type:

(pseudo-)first order (= half-life)

Key result

pH:

4

Temp.:

25 °C

DT50:

< 5 min

Type:

(pseudo-)first order (= half-life)

pH:

4

Temp.:

35 °C

DT50:

< 5 min

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

15 °C

Hydrolysis rate constant:

0.01 min-1

DT50:

111 min

Type:

(pseudo-)first order (= half-life)

Key result

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

0.01 min-1

DT50:

99 min

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

35 °C

Hydrolysis rate constant:

0.01 min-1

DT50:

86 min

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

15 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

105 h

Type:

(pseudo-)first order (= half-life)

Key result

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

85 h

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

35 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

62 h

Type:

(pseudo-)first order (= half-life)

Reference 2

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-10-08 to 2009-11-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

The hydrolysis was examined at three different pH values: 4.0, 7.0 and 9.0 at three different temperatures: around 15, 25 and 35 °C 0.5 C in the dark.

Details on test conditions:

Stock solution: 1 mg/mL
Approximately 25 mg of the test item was weighed into a 25 mL volumetric flask. It was filled up to the mark with dried acetone and thoroughly mixed.

Duration:

25 min

pH:

4

Temp.:

15 °C

Initial conc. measured:

52.6 other: µg/mL

Duration:

25 min

pH:

4

Temp.:

25 °C

Initial conc. measured:

56.1 other: µg/mL

Duration:

15 min

pH:

4

Temp.:

35 °C

Initial conc. measured:

38.7 other: µg/mL

Duration:

330 min

pH:

7

Temp.:

15 °C

Initial conc. measured:

8.16 other: µg/mL

Duration:

300 min

pH:

7

Temp.:

25 °C

Initial conc. measured:

6.38 other: µg/mL

Duration:

270 min

pH:

7

Temp.:

35 °C

Initial conc. measured:

6.69 other: µg/mL

Duration:

187 h

pH:

9

Temp.:

15 °C

Initial conc. measured:

8.04 other: µg/mL

Duration:

187 h

pH:

9

Temp.:

25 °C

Initial conc. measured:

7.38 other: µg/mL

Duration:

190 h

pH:

9

Temp.:

35 °C

Initial conc. measured:

8.8 other: µg/mL

Number of replicates:

Two replicate samples were analysed at each time point, except for pH 4 test, where we have three replicate data points.

Positive controls:

no

Negative controls:

yes

Statistical methods:

The chromatograms were evaluated with the help of “LaChrom” chromatogram processor software. Calculations were carried out using “EXCEL for Windows". The calibration curves were constructed with “STATISTICA for Windows" using weighted linear regression. The factor was 1/concentration.

Preliminary study:

As the test item proved to be unstable during analytical method validation trials, the preliminary test is not required.

Transformation products:

yes

No.:

#1

No.:

#2

Details on hydrolysis and appearance of transformation product(s):

The degradation products following hydrolysis are 2,2-dimethyl-3-oxopropyl dodecanoate (CAS # 102985-93-3) and 3-aminomethyl-3,5,5-trimethylcyclohexylamine (CAS # 2855-13-2).

% Recovery:

0.9

pH:

4

Temp.:

15 °C

Duration:

25 min

% Recovery:

1.7

pH:

4

Temp.:

25 °C

Duration:

25 min

% Recovery:

0.5

pH:

4

Temp.:

35 °C

Duration:

15 min

% Recovery:

12

pH:

7

Temp.:

15 °C

Duration:

330 min

% Recovery:

13

pH:

7

Temp.:

25 °C

Duration:

300 min

% Recovery:

11

pH:

7

Temp.:

35 °C

Duration:

270 min

% Recovery:

28

pH:

9

Temp.:

15 °C

Duration:

187 h

% Recovery:

20

pH:

9

Temp.:

25 °C

Duration:

187 h

% Recovery:

10

pH:

9

Temp.:

35 °C

Duration:

190 h

pH:

4

Temp.:

15 °C

DT50:

< 5 min

Type:

(pseudo-)first order (= half-life)

Key result

pH:

4

Temp.:

25 °C

DT50:

< 5 min

Type:

(pseudo-)first order (= half-life)

pH:

4

Temp.:

35 °C

DT50:

< 5 min

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

15 °C

Hydrolysis rate constant:

0.01 min-1

DT50:

111 min

Type:

(pseudo-)first order (= half-life)

Key result

pH:

7

Temp.:

25 °C

Hydrolysis rate constant:

0.01 min-1

DT50:

99 min

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

35 °C

Hydrolysis rate constant:

0.01 min-1

DT50:

86 min

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

15 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

105 h

Type:

(pseudo-)first order (= half-life)

Key result

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

85 h

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

35 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

62 h

Type:

(pseudo-)first order (= half-life)

Details on results:

Hydrolysis rate at pH 4 was above 90 % at the first analysis, therefore t1/2 is considered to be less than 5 minutes at each of the three temperatures.
At pH 7 the reaction lasted for about five hours, the calculated t1/2 is 86 – 111 minutes for the different temperatures.
At pH 9 the reaction proved to be slower, it lasted for eight days. The calculated t1/2 is 62 - 105 hours depending on the applied temperature.

Measured data at pH 4

Temperature, pH	Sampling time, min	Measured concentration, µg/mL (mean of two or three)	Hydrolysis rate, %	Measured pH
15 °C, pH4	Start	Control	-	4.00
	Start	Control with acetone	-	6.23
	Start	52.6	-	6.25
	5	1.19	97.7	-
	10	0.77	98.5	-
	15	0.82	98.4	-
	20	0.66	98.7	-
	25	0.47	99.1	6.25
25 °C, pH4	Start	Control	-	4.01
	Start	Control with acetone	-	6.26
	Start	56.1	-	6.26
	5	2.78	95.0	-
	10	2.38	95.8	-
	15	1.57	97.2	-
	20	0.82	98.5	-
	25	0.97	98.3	6.24
35 °C, pH4	Start	Control	-	4.00
	Start	Control with acetone	-	6.22
	Start	38.7	-	6.24
	5	0.99	97.4	-
	10	0.42	98.9	-
	15	0.19	99.5	6.25

 

Measured data at pH 7

Temperature, pH	Sampling time, min	Measured concentration, µg/mL (mean of two)	Hydrolysis rate, %	Measured pH
15 °C, pH7	Start	Control	-	7.00
	Start	Control with acetone	-	7.22
	Start	8.16	-	7.22
	60	5.13	37	7.20
	90	4.40	46	7.22
	120	3.25	60	7.19
	150	2.89	65	7.21
	180	2.55	69	7.20
	210	2.13	74	7.20
	240	1.94	76	7.19
	270	1.39	83	7.20
	300	1.10	86	7.22
	330	1.00	88	7.21
25 °C, pH7	Start	Control	-	7.01
	Start	Control with acetone	-	7.20
	Start	6.38	-	7.23
	20	4.87	24	7.21
	40	4.79	25	7.21
	60	4.44	30	7.21
	120	3.61	43	7.21
	150	2.19	66	7.20
	180	2.12	67	7.21
	210	1.27	80	7.22
	240	1.02	84	7.21
	270	1.04	84	7.21
	300	0.81	87	7.20
35 °C, pH7	Start	Control	-	7.01
	Start	Control with acetone	-	7.21
	Start	6.69	-	7.20
	30	5.04	25	7.20
	60	4.21	37	7.21
	90	3.57	47	7.22
	120	2.69	60	7.22
	150	2.25	66	7.22
	180	1.85	72	7.21
	210	1.63	76	7.22
	240	0.80	88	7.22
	270	0.72	89	7.22

 

Measured data at pH 9

Temperature, pH	Sampling time, hours	Measured concentration, µg/mL (mean of two)	Hydrolysis rate, %	Measured pH
15 °C, pH9	Start	Control	-	9.01
	Start	8.04	-	9.01
	19	6.72	16	9.00
	24	6.83	15	9.00
	41	5.78	28	9.01
	67	4.45	45	9.00
	74	4.45	45	8.99
	118	3.27	59	9.00
	163	2.87	64	9.00
	187	2.22	72	9.00
25 °C, pH9	Start	Control	-	9.00
	Start	7.38	-	9.00
	19	6.58	11	9.00
	24	5.16	30	9.00
	41	4.53	39	9.01
	67	3.79	49	9.00
	74	3.60	51	9.01
	118	2.76	63	9.00
	163	1.91	74	9.00
	187	1.46	80	9.01
35 °C, pH9	Start	Control	-	9.01
	Start	8.80	-	9.01
	21	6.68	28	9.00
	26	6.32	32	9.01
	30	6.20	33	9.01
	45	6.03	35	9.00
	70	4.08	56	8.99
	77.5	3.79	59	9.00
	121.5	2.40	74	9.01
	166	1.56	83	9.01
	190	0.98	90	9.00

 

Rate constants and half-lives based on the measured data

pH	Temperature	Slope	kobs	t1/2
4	15 °C	-	-	< 5 min
	25 °C	-	-	< 5 min
	35 °C	-	-	< 5 min
7	15 °C	-0.006229	0.006229	111 min
	25 °C	-0.006970	0.006970	99min
	35 °C	-0.008033	0.008033	86 min
9	15 °C	-0.006583	0.006583	105 hours
	25 °C	-0.008150	0.008150	85 hours
	35 °C	-0.011115	0.011115	62 hours

Validity criteria fulfilled:

yes

Conclusions:

Hydrolysis of the test item was most rapid in acidic environment (pH 4) and high temperature compared to basic environment (pH 9) and low temperature:
At pH 4, the half-life t1/2 at 15 °C, 25 °C and 35 °C was <5 min. At pH 7, the t1/2 at 15 °C was 111 min, at 25 °C – 99 min, and at 35 °C – 86 min. At pH 9, the half-life was determined to be 105 hours at 15 °C, 85 hours at 25 °C and 62 hours at 35 °C, respectively.
The degradation products following hydrolysis are 2,2-dimethyl-3-oxopropyl dodecanoate (CAS # 102985-93-3) and 5-amino-1,3,3-trimethyl-cyclohexanemethylamine (CAS # 2855-13-2).

Executive summary:

Determination of the hydrolysis of the test item as a function of pH was performed according to OECD 111 and EU method C.7 in a study according to GLP. Abiotic degradation of the test item was assessed in solutions of different pH values. Hydrolysis was most rapid in acidic environment (pH 4) and high temperature compared to basic environment (pH 9) and low temperature:

pH, t1/2 at 15 °C 25 °C 35 °C

4, < 5 min < 5 min < 5 min

7, 111 min 99 min 86 min

9, 105 hours 85 hours 62 hours

Due to the small number of microorganisms present in the test mixtures (5 - 25 microorganisms/mL test mixture), there was a very low possibility of microbial decomposition. Based on the above results a potential for chemical decomposition (hydrolysis) is indicated. The degradation products following hydrolysis are 2,2-dimethyl-3-oxopropyl dodecanoate (CAS # 102985-93-3) and 5-amino-1,3,3-trimethyl-cyclohexanemethylamine (CAS # 2855-13-2).

Reference 3

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

from 2009-05-28 to 2009-07-02

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non GLP study on analytical method development

Qualifier:

no guideline followed

Principles of method if other than guideline:

Non-GLP study on analytical method development for Sika Hardener LG in different aqueous media.

GLP compliance:

no

Remarks:

Non-GLP study on method validation.

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Measurements in different media (ISO medium, OECD medium). Measurements at 7 - 53 min after addition of the test item to the medium.

Buffers:

ISO Medium and OECD Medium

Details on test conditions:

Measurements at 7 - 53 min after addition of the test item to the medium.

Duration:

53 min

pH:

7

Temp.:

20

Initial conc. measured:

1 mg/L

Statistical methods:

The chromatograms were evaluated with the help of LCQ Xcalibur data system.

Transformation products:

not measured

Details on hydrolysis and appearance of transformation product(s):

The validation report shows, that only 1 % of nominal concentration of Sika Hardener LG could be detected in ISO medium after 47 min. In OECD medium 67 % of nominal concentration was detected after 44 min.

% Recovery:

1

pH:

7

Temp.:

20 °C

Duration:

47 min

Remarks on result:

other: in ISO medium

% Recovery:

67

pH:

7

Temp.:

20 °C

Duration:

44 min

Remarks on result:

other: in OECD medium

Key result

pH:

7

Temp.:

20 °C

DT50:

< 44 min

 

Table 1. Decomposition of Sika Hardener LG in aquatic media (05 June 2009)
Matrix	Elapsed time (min)	Concentration in percentage of nominal
ISO Medium	7	0 %
	15	0 %
	22	0 %
	30	0 %
	38	0 %
	45	0 %
OECD Medium	14	0 %
	22	0 %
	30	0 %
	37	0 %
	45	0 %
	53	0 %

 

Table 2. Decomposition of Sika Hardener LG in aquatic media (Experiment II. 09 June 2009)
Matrix	Elapsed time (min)	Concentration in percentage of nominal
ISO Medium	9	62 %
	17	24 %
	24	4 %
	32	4 %
	40	2 %
	47	1 %
OECD Medium	6	94 %
	13	90 %
	21	*
	29	84 %
	37	74 %
	44	67 %

* chromatographic error

Validity criteria fulfilled:

not applicable

Conclusions:

The validation report shows, that only 1 % of nominal concentration of Sika Hardener LG could be detected in ISO medium after 47 min. In OECD medium 67 % of nominal concentration was detected after 44 min.

Executive summary:

The validation report shows, that only 1 % of nominal concentration of Sika Hardener LG could be detected in ISO medium after 47 min. In OECD medium 67 % of nominal concentration was detected after 44 min. Recovery from aqueous solutions could not be determined, due to the very rapid hydrolyses of Sika Hardener LG from the solution.

Description of key information

In a weight of evidence approach, based on data from method development and data from a structural analogue, it can be shown that the DT50 of Sika Hardener LG is far below 12 hours. The degradation products following hydrolysis are the aldehyde 2,2-dimethyl-3-oxopropyl dodecanoate (CAS # 102985-93-3) and the amine 2-(2-Aminoethoxy)ethanol (CAS # 929-06-6).

Additional information

No state of the art hydrolysis study is available for Sika Hardener LG. This endpoint is not required for a tonnage band of 1-10 t/a, but supporting data are provided to justify waivers for physical/chemical endpoints like water solubility.

In a weight of evidence approach data from the analytical method development with Sika Hardener LG and a state of the art study with the analogous substance Sika Hardener LI is presented.

Analytical determination of test item is technically not feasible due to the fast hydrolysis. The validation report (LAB, 2009) shows, that only 1 % of nominal concentration of Sika Hardener LG could be detected in ISO medium after 47 min. In OECD medium 67 % of nominal concentration was detected after 44 min. The degradation products following hydrolysis are the aldehyde 2,2-dimethyl-3-oxopropyl dodecanoate (CAS # 102985-93-3) and the amine 2-(2-Aminoethoxy)ethanol (CAS # 929-06-6).

The statement of fast hydrolysis based on the validation report is supported by a read-across approach from a full hydrolysis study (Laky, 2009) that was performed with another structural analogue - Sika Hardener LI. Both substances are aldimines sharing the same aldehyde component (2,2-Dimethyl-3-lauroyloxy-propanal, CAS # 102985-93-3) and only differ in the amine component. Data from the OECD toolbox supports the use of data from Sika Hardener LI also as read-across for Sika Hardener LG (see attachment in section 13).

Sika Hardener LI was assessed in an abiotic degradation study, according to EU-method C.7 and OECD guideline no. 111. Hydrolysis of Sika Hardener LI was most rapid in acidic environment (pH 4) and high temperature compared to basic environment (pH 9) and low temperature. The DT50 at pH 7 and 25 °C and 15 °C and was 99 min and 111 min, respectively.

In conclusion, it can be stated that the half-life of Sika Hardener LG is by far below 12 hours.