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Hydrolysis

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Endpoint:
hydrolysis
Remarks:
Investigation of hydrolysis products of 2 X similar substances (26322-14-5 & 53220-22-7) as weight of evidence of substance similarity.
Type of information:
experimental study
Remarks:
Study Based on OECD 111 adapted for degradation product determination
Adequacy of study:
supporting study
Study period:
January- February 2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study is a non-standard investigation of degradation products and is reliable a weight of evidence only.
Remarks:
Parent solubility makes standard hydrolysis study technically unachievable. This study follows parent and degradation products spiked initially above the water solubility to allow a comparison of degradation profiles between two similar materials
Justification for type of information:
Study conducted to allow a comparison of degradation profiles between two similar materials at pH 7 (20ºC) and pH1.2 (37 ºC)
Qualifier:
no guideline required
Version / remarks:
methodology was based on OECD 111. However in order to generate sufficient degradation products to allow detection a concentration far in excess of the water solubilty was required. hence the study is adapted to allow a degradation product profile comparison.
Principles of method if other than guideline:
Test material was spiked with solvent in excess of the solubility limit. pH7 at 20ºC and pH1.2 at 37ºC only were investigated. The study duration was continued until parent material exhaustion (complete degradation) in the ph1.2 37ºC replicates. NMR analysis was used to follow the parent and all of the formed degradation products and allow comparison between the behaviour of two similar materials.
GLP compliance:
no
Specific details on test material used for the study:
26322-14-5 Dicetyl peroxydicarbonate Batch Lot:1011540230
53220-22-7 Dimyristyl peroxydicarbonate Batch Lot:1101530021
Radiolabelling:
no
Analytical monitoring:
yes
Remarks:
NMR
Details on sampling:
6 samples were taken over the test perod of both test substances under both conditions. Due to the tendency for both the parent materials and the expected degradation products to adsorb strongly to the glass vessels. The entire test vessel was extracted with deuterated chloroform at each time point.
Buffers:
The pH buffers pH 1.2 and pH 7 were made according to Clak and Lubs, described in Annex 3 of OECD guideline 111 (OECD, 2004).
De initial spiked concentrations wasl 50 mg/L. Spiking was conducted by accurale transfer of 9.9 mL buffer into a test vial followed by the addition of 0.1 mL stock (in DCM) creating an initial nominal concentration of 50mg/L
Positive controls:
yes
Negative controls:
no
Statistical methods:
N/A
Transformation products:
yes
Details on hydrolysis and appearance of transformation product(s):
Both test substances 26322-14-5 & 53220-22-7 were found to degrade to their corresponding alcohols at 20ºC pH7 only. At pH 1.2 and 37ºC the same alcohols were found at approximately 50% of the expected concentration based on the initial test concentration. The remaining substances were identified as the corresponding Fatty acids,Esters,Carbonates and Ketones. ID was confirmed by the analysis of pure analytical standards.


Fatty acids R-COOH
Dialkyl esters R-CO-O-R
Dialkyl carbonates R-O-CO-O-R
Di alkyl ketones R-CO-R

R = Alkyl group

Results with reference substance:
Known standards of the expected main degradation products cetyl and myristyl alcohol were extracted to determine the extraction efficiency of the sample preparation method and quantification. Pure analytical standards were analyzed to determine the additional products identified under acidic conditions for both test substances. Extraction efficiecy of the Cetyl and Myristly alcohol was >80%. Measured recovery of the parent materials at T=0 was > 90%. Mass balance of the main degradation products and the other degradation products at the end of the study (3 weeks) at pH1.2 and 37ºC for Dicetylperoxydicarbonate was >80% based on the nominal spiked concentration of parent material. This test method was considered of sufficient accuracy to determine the parent material and it degradation products.

Results

Parent material concentrations and increase in main degradation product during study:

 pH

 Substance

 Chemical Name

 

mg/kg

 

 

 

 

 

 

 

 

Mw

t=0

t=24

t=72h

t=144h

2wk

3wk

 

 

 

 

16-Jan

17-Jan

19-Jan

22-Jan

30-Jan

06-Feb

pH=1.2

26322 -14 -5

Dicetylperoxydicarbonate

570.5

48.7

43.5

30.2

16.6

3.7

1.5

 

C16-Ol

Cetylalcohol

242.4

2.7

6.1

13.7

18.2

22.5

21.8

 

 

 

 

 

 

 

 

 

 

pH=7

 26322 -14 -5

Dicetyl peroxydicarbonate

570.5

48.0

49.4

44.5

44.9

46.1

43.0

 

C16-Ol

Cetyl alcohol

242.4

3.1

3.3

3.7

4.6

4.4

3.8

 

 

 

 

 

 

 

 

 

 

pH=1.2

53220-22-7

Dimyristyl peroxydicarbonate

514.8

48.9

40.6

22.3

9.6

0.9

0.0

 

C14-Ol

Myristyl alcohol

214.4

1.4

7.8

15.4

19.8

22.1

21.8

 

 

 

 

 

 

 

 

 

 

pH=7

 53220-22-7

Dimyristyl peroxydicarbonate

514.8

50.9

49.9

47.4

46.9

47.6

43.4

 

C14-Ol

Myristyl alcohol

214.4

1.7

1.8

2.2

3.3

3.8

4.8

Endpoint:
hydrolysis
Data waiving:
study technically not feasible
Justification for data waiving:
the study does not need to be conducted because the substance is readily biodegradable
the study does not need to be conducted because the substance is highly insoluble in water

Description of key information

A standard study has been waived due to ready biodegradability and solubility limitations making the study technically unachievable. Additional degradation information has been provided for 26322-14-5 & 53220-22-7 to illustrate substance similarity.

Key value for chemical safety assessment

Additional information