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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
hydrolysis
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
1. SOFTWARE
EPI (Estimation Programs Interface) Suite, EPA’s and Syracuse Research Corp. (SRC)

2. MODEL (incl. version number)
HYDROWIN v2.00

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
O=C(OCCO)CC(C(=O)OCCO)CP2(=O)Oc3c(c1c2cccc1)cccc3

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: hydrolysis rate constant
- Unambiguous algorithm: Esters: log Kb  =  0.92Es{R1} + 0.31Es{R2} + 2.16 sigma*{R1} + 2.30 sigma*{R2} + 2.10 sigmaX{R1} + 1.25 sigmaX{R2} + 2.67
where Es is the steric factor at the designated position, sigma* is the Taft constant at the designated position, and sigmaX is the Hammett constant at the designated position.


5. APPLICABILITY DOMAIN

- Descriptor domain: esters
- Similarity with analogues in the training set: ester groups

6. ADEQUACY OF THE RESULT
Following half-lifes were calculated:
Kb Half-Life at pH 8: 132.459 days
Kb Half-Life at pH 7: 3.627 years
It is concluded that Bis(2-hydroxyethyl)(6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)succinate P-oxide will not hydrolyze at envirinmental relevant pH. The estimated half-life is > 16 days.
Qualifier:
no guideline followed
Principles of method if other than guideline:
Calculation based on HYDROWIN v2.00, Estimation Programs Interface Suite™ for Microsoft® Windows v 4.10. US EPA, United States Environmental Protection Agency, Washington, DC, USA.
The program HYDROWIN calculates a base-catalyzed rate constant for esters from the following equation: 

log Kb  =  0.92Es{R1} + 0.31Es{R2} + 2.16 sigma*{R1} + 2.30 sigma*{R2} + 2.10 sigmaX{R1} + 1.25 sigmaX{R2} + 2.67 

where Es is the steric factor at the designated position, sigma* is the Taft constant at the designated position, and sigmaX is the Hammett constant at the designated position.
GLP compliance:
no
Estimation method (if used):
 HYDROWIN calculates a base-catalyzed rate constant for esters from the following equation:

log Kb  =  0.92Es{R1} + 0.31Es{R2} + 2.16 sigma*{R1} + 2.30 sigma*{R2} + 2.10 sigmaX{R1} + 1.25 sigmaX{R2} + 2.67

 

where Es is the steric factor at the designated position, sigma* is the Taft constant at the designated position, and sigmaX is the Hammett constant at the designated position.
The ester equation regression had the following statistics (Mill et al, 1987):

  number = 124

  correlation coef (r) = 0.982

  correlation coef (r2) = 0.965
Transformation products:
not specified
Key result
pH:
7
Temp.:
20 °C
DT50:
3.627 yr
Type:
not specified
Key result
pH:
8
Temp.:
20 °C
Hydrolysis rate constant:
0.061 s-1
DT50:
132.5 d
Type:
not specified
Validity criteria fulfilled:
not applicable
Conclusions:
Following half-lifes were calculated:
Kb Half-Life at pH 8: 132.459 days
Kb Half-Life at pH 7: 3.627 years
It is concluded that Bis(2-hydroxyethyl)(6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)succinate P-oxide will not hydrolyze at envirinmental relevant pH. The estimated half-life is > 16 days.
Executive summary:

Following half-lifes were calculated:

Kb Half-Life at pH 8:     132.459  days  

Kb Half-Life at pH 7:       3.627  years  

It is concluded that Bis(2-hydroxyethyl)(6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)succinate P-oxide will not hydrolyze at envirinmental relevant pH. The estimated half-life is > 16 days.

Description of key information

Calculation based on HYDROWIN v2.00, Estimation Programs Interface Suite™ for Microsoft® Windows v 4.10. US EPA, United States Environmental Protection Agency, Washington, DC, USA:

Following half-lifes were calculated:

Kb Half-Life at pH 8:     132.459  days  

Kb Half-Life at pH 7:       3.627  years  

It is concluded that Bis(2-hydroxyethyl)(6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)succinate P-oxide will not hydrolyze at envirinmental relevant pH. The estimated half-life is > 16 days.

Key value for chemical safety assessment

Half-life for hydrolysis:
3.6 yr
at the temperature of:
25 °C

Additional information