Reaction mass of substituted-(naphthalen-1-methyl)heteromonocyclic chloride and propane-1,2-diol

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental Starting Date: 20 July 2012; Experimental Completion Date: 23 January 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.2120 (Hydrolysis of Parent and Degradates as a Function of pH at 25°C)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Test material form:

other: solid

Radiolabelling:

no

Study design

Analytical monitoring:

yes

Details on sampling:

Preparation of the Test Solutions:
Sample solutions were prepared in stoppered glass flasks at a nominal concentration of 0.500 g/L in the three buffer solutions.

The concentration of each solution did not exceed the lesser of 0.01 mol/L or half the water solubility.

The test solutions were split into individual vessels for each data point.

The solutions were shielded from light whilst maintained at the test temperature

Preliminary test/tier 1:
Sample solutions at pH 4, 7 and 9 were maintained at 50.0 ± 0.5 °C for a period of 120 hours.

Tier 2:

Results from the preliminary test/tier 1 showed it was necessary to undertake further testing at pH 9. Sample solutions were maintained at 50.0 ± 0.5, 60.0 ± 0.5 °C and 70.0 ± 0.5 °C for periods of 239 hours, 141¼ hours and 48 hours respectively.

Analysis of sample solutions:
Duplicate vessels of sample solutions for each pH were taken from the waterbath at various times and the pH of each solution recorded. The concentration of the sample solution was determined by high performance liquid chromatography (HPLC).

Samples:
An aliquot of each pH 4 and pH 7 sample solution was diluted by a factor of 10 using dimethyl sulfoxide.

An aliquot of each pH 9 sample solution was diluted by a factor of 10 using acidified dimethyl sulfoxide.

Standards:
For pH 4 and pH 7 sample solution analysis, duplicate standard solutions of test item were prepared in dimethyl sulfoxide: relevant buffer solution (90:10 v/v) at a nominal concentration of 50 mg/L.
For pH 9 sample solution analysis, duplicate standard solutions of test item were prepared in acidified dimethyl sulfoxide : pH 9 buffer solution (90:10 v/v) at a nominal concentration of 50 mg/L.

Matrix blanks:
For pH 4 and pH 7 sample solution analysis, dimethyl sulfoxide: relevant buffer solution (90:10 v/v).

For pH 9 sample solution analysis, acidified dimethyl sulfoxide: pH 9 buffer solution (90:10 v/v).

Buffers:

The test system uses sterile buffer solutions at pH's 4.0, 7.0 and 9.0

Specification of buffer solutions:
Buffer Solution (pH 4)
Components: Citric acid, Sodium chloride, Sodium hydroxide
Concentration (mol dm-3): 0.06, 0.04, 0.07

Buffer Solution (pH7)
Components: Disodium hydrogen orthophosphate (anhydrous), Potassium dihydrogen orthophosphate, Sodium chloride
Concentration (mol dm-3): 0.03, 0.02, 0.02

Buffer Solution (pH9)
Components: Disodium tetraborate, Sodium chloride
Concentration (mol dm-3): 0.01, 0.02

Details on test conditions:

Refer to details on sampling and analytical methods.

Duration of test

Duration of test 1

Duration:

120 h

Temp.:

50 °C

Initial conc. measured:

0.478 - 0.504 g/L

Duration of test 2

Duration:

239 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

0.534 g/L

Duration of test 3

Duration:

141.25 h

pH:

9

Temp.:

60 °C

Initial conc. measured:

0.534 g/L

Duration of test 4

Duration:

48 h

pH:

9

Temp.:

70 °C

Initial conc. measured:

0.516 g/L

Number of replicates:

Duplicate

Positive controls:

no

Negative controls:

no

Results and discussion

Preliminary study:

See any other information on results incl. tables.

Test performance:

Validation:
The linearity of the detector response with respect to concentration was assessed over the nominal concentration range of 0 to 100 mg/L. This was satisfactory with a correlation coefficient of 1.000 being obtained for the analysis matrices relevant to all three pHs.

Transformation products:

not measured

Dissipation DT50 of parent compound

Dissipation DT50 of parent compound 1

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Type:

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

Dissipation DT50 of parent compound 2

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Type:

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

Dissipation DT50 of parent compound 3

pH:

9

Temp.:

25 °C

DT50:

82.7 d

Type:

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

Details on results:

See any other information on results incl. tables.

Any other information on results incl. tables

Results

Preliminary test/Tier 1

The mean peak areas relating to the standard and sample solutions are shown in attached background material.

The test item concentrations at the given time points are shown in the following tables:

pH 4 at 50.0 ± 0.5 ºC 

Timepoint (hours)	Sample Replicate	Concentration (g/L)	% of Mean Initial Concentration
Initial	A	0.504	100
	B	0.504	100
24	A	0.515	102
	B	0.516	102
120	A	0.510	101
	B	0.508	101

 Result:             Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.

pH 7 at 50.0 ± 0.5 ºC 

Timepoint (hours)	Sample Replicate	Concentration (g/L)	% of Mean Initial Concentration
Initial	A	0.495	99.8
	B	0.497	100
24	A	0.500	101
	B	0.500	101
120	A	0.471	95.1
	B	0.471	95.0

 Result:             Less than 10% hydrolysis after 5 days at 50 °C, equivalent to a half-life greater than 1 year at 25 °C.

pH 9 at 50.0 ± 0.5 ºC

Timepoint (hours)	Sample Replicate	Concentration (g/L)	% of Mean Initial Concentration
Initial	A	0.478	99.6
	B	0.481	100
24	A	0.416	86.7
	B	0.412	85.9
120	A	0.242	50.6
	B	0.242	50.4

 Result:             The extent of hydrolysis after 120 hours indicated that a further test (Tier 2), conducted at 50.0, 60.0 and 70.0°C, was required to estimate the rate constant and half-life.

Tier 2

The mean peak area relating to the standard and sample solutions are shown in attached background material.

The test item concentrations at the given time points are shown in the following tables:

 

pH 9 at 50.0 ± 0.5 ºC

 

Timepoint (hours)	Sample Replicate	Concentration (g/L)	Log10[concentration (g/L)]	% of Mean Initial Concentration
Initial	A	0.534	-0.272	99.9
	B	0.535	-0.272	100
51¼	A	0.386	-0.414	72.1
	B	0.387	-0.412	72.4
72	A	0.341	-0.467	63.8
	B	0.339	-0.470	63.4
118	A	0.257	-0.589	48.1
	B	0.261	-0.583	48.8
168	A	0.196	-0.709	36.6
	B	0.195	-0.710	36.4
239	A	0.132	-0.880	24.7
	B	0.131	-0.882	24.6

 

Result: Slope     =         -2.54 x 10^-4 (see Figure 3.4 - Graph of log₁₀ Concentration (g/L) versus Time (Hours) - attached background material).
k_obs                  =         5.84 x 10^-3 hour^-1
                       =         1.62 x 10^-6 second^-1
t_½                   =         119 hours

 

pH 9 at 60.0 ± 0.5 ºC

 

Timepoint (hours)	Sample Replicate	Concentration (g/L)	Log10[concentration (g/L)]	% of Mean Initial Concentration
Initial	A	0.534	-0.272	99.9
	B	0.535	-0.272	100
24	A	0.354	-0.451	66.3
	B	0.354	-0.451	66.2
48	A	0.241	-0.618	45.1
	B	0.240	-0.620	44.9
72	A	0.175	-0.758	32.7
	B	0.167	-0.776	31.3
96	A	0.116	-0.934	21.8
	B	0.116	-0.934	21.8
118	A	8.10 x 10^-2	-1.091	15.2
	B	8.03 x 10^-2	-1.095	15.0
141¼	A	5.40 x 10^-2	-1.268	10.1
	B	5.32 x 10^-2	-1.274	9.96

 

Result: Slope      =         -6.97 x 10^-3 (see Figure 3.5 - Graph of log₁₀ Concentration (g/L) versus Time (Hours) - attached background material).
k_obs                  =         1.60 x 10^-2 hour^-1
                       =         4.46 x 10^-6 second^-1
t_½                   =         43.2 hours

pH 9 at 70.0 ± 0.5 ºC

 

Timepoint (hours)	Sample Replicate	Concentration (g/L)	Log10[concentration (g/L)]	% of Mean Initial Concentration
Initial	A	0.516	-0.287	99.9
	B	0.517	-0.286	100
3	A	0.461	-0.336	89.2
	B	0.460	-0.337	89.1
5½	A	0.408	-0.389	79.0
	B	0.413	-0.384	80.0
22½	A	0.202	-0.695	39.1
	B	0.202	-0.694	39.2
25½	A	0.179	-0.747	34.6
	B	0.180	-0.745	34.8
28½	A	0.159	-0.799	30.8
	B	0.160	-0.797	30.9
48	A	7.12 x 10^-2	-1.148	13.8
	B	7.10 x 10^-2	-1.149	13.8

 

Result: Slope      =         -1.80 x 10^-2 (see Figure 3.6 - Graph of log₁₀ Concentration (g/L) versus Time (Hours) - attached background material).
k_obs                  =         4.14 x 10^-2hour^-1
                       =         1.15 x 10^-5 second^-1
t_½                   =         16.7 hours

The Arrhenius plot was constructed using the data shown in the following table:

 

pH 9 Arrhenius Data

 

T (ºC)	T (K)	1 / T (K)	kobs (hr-1)	Ln kobs
50.0	323.15	3.10 x 10^-3	5.84 x 10^-3	-5.143
60.0	333.15	3.00 x 10^-3	1.60 x 10^-2	-4.133
70.0	343.15	2.91 x 10^-3	4.14 x 10^-2	-3.184

 

From the graph (Figure 3.7 - Graph of In.k_obs versus 1/T (K), attached background material) of the above data, the rate constant and half-life at 25°C have been estimated to be as follows:

 

k_obs    =         3.49 x 10^-4 hour^-1
           =         9.71 x 10^-8 second^-1
t_½       =         1.98 x 10³ hours
           =         82.7 days

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The hydrolysis characteristics of the test item have been quantified for the substituted-(naphthalen-1-methyl)heteromonocyclic chloride content of the test item. The rate constant and estimated half-life at 25 °C of the test item are summarised below:

The rate constant and estimated half-life at 25 °C of the test item are:
pH 4: Rate constant (s-1): not applicable
Estimated half-life at 25°C: >1 year

pH 7: Rate constant (s-1): not applicable
Estimated half-life at 25°C: >1 year

pH 9: Rate constant (s-1): 9.71 x 10-8
Estimated half-life at 25°C: 82.7 days

No hydrolysis testing was relevant to the propane-1,2-diol content of the test item, as it did not contain any hydrolysable functional groups and also from available information, it was expected to be readily biodegradable.

Executive summary:

Method:

The determination was carried out using a procedure designed to be compatible with Method C7 Abiotic Degradation, Hydrolysis as a Function of pH of Commission Regulation (EC) No 440/2008 of 30 May 2008, Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004, and Method 835.2120 of the OPPTS Guidelines.

 

The test system uses sterile buffer solutions at pH’s 4.0, 7.0 and 9.0.

 

Results

The hydrolysis characteristics of the test item have been quantified for the substituted-(naphthalen-1-methyl)heteromonocyclic chloride content of the test item. The rate constant and estimated half-life at 25°C of the test item are shown in the following table:

 

pH	Rate constant (s^-1)	Estimated half-life at 25°C
4	not applicable	>1 year
7	not applicable	>1 year
9	9.71 x 10^-8	82.7 days

 

 

No hydrolysis testing was relevant to the propane-1,2-diol content of the test item, as it did not contain any hydrolysable functional groups and also from available information, it was expected to be readily biodegradable.