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EC number: 460-110-3 | CAS number: 797751-43-0 WASOX-MMAC2
Partition coefficient
Administrative data
Link to relevant study record(s)
- Endpoint:
- partition coefficient
- Data waiving:
- study technically not feasible
- Justification for data waiving:
- the study does not need to be conducted because the substance decomposes
- Justification for type of information:
- JUSTIFICATION FOR DATA WAIVING
According to Column 2 of REACH Annex VII, the study cannot be conducted since the substance undergoes rapid hydrolysis (half-life < 1h) in aqueous to acetone oxime and the corresponding silanols. Moreover, these silanols undergo continuous condensation reactions to produce higher molecular weight siloxanes which are considered biologically unavailable. - Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Remarks:
- According to OECD Guideline 107, with GLP.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
- Qualifier:
- according to guideline
- Guideline:
- EU Method A.8 (Partition Coefficient)
- GLP compliance:
- yes
- Type of method:
- other: shake flask and HPLC methods
- Partition coefficient type:
- octanol-water
- Remarks on result:
- other: An experimental determination of the partition coefficient could not be performed
- Conclusions:
- The partition coefficient n-octanol/water assay for the test material Wasox-MMAC2 could not be performed.
- Executive summary:
The experimental determination of the partition coefficient n-octanol/water assay for the test material Wasox-MMAC2 according to OECD Guideline 107, shake flask method or high performance liquid chromatography (HPLC), could not be performed, because:
1) the test substance rapidly degrades with a half-life time of <1 hour at 25°C, see separate report on the hydrolysis
2) the test substance is a mixture of several compounds for which the shake-flask method is not applicable.
3) the test substance reacts with water (eluent), and in this case the HPLC method is not applicable.
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Remarks:
- A scientific publication, peer reviewed. No GLP.
- Principles of method if other than guideline:
- No data provided on the method.
- GLP compliance:
- no
- Partition coefficient type:
- octanol-water
- Type:
- log Pow
- Partition coefficient:
- 0.2
- Remarks on result:
- other: The temparature value is not provided
- Conclusions:
- Partition coefficients expressed as Log Pow of acetone oxime is 0.20.
- Executive summary:
Partition coefficients expressed as Log Pow of acetone oxime is 0.20.
- Endpoint:
- partition coefficient
- Type of information:
- (Q)SAR
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
- Remarks:
- Internationally accepted method, EPI-Suite, EPA (USA)
- Justification for type of information:
- See attached the QMRF and QPRF for the QSAR model
- Guideline:
- other: REACH Guidance on QSARs R.6
- Principles of method if other than guideline:
- Meylan, W.M. and P.H. Howard. 1995. Atom/fragment contribution method for estimating octanol water partition coefficients. J. Pharm. Sci. 84: 83-92.
- Specific details on test material used for the study:
- SMILES: N(O)=C(C)C
- Type:
- log Pow
- Partition coefficient:
- 1.2
- Remarks on result:
- other: QSAR predicted value
- Conclusions:
- The estimated log octanol-water partition coefficient (Log Kow) is 1.20 (EPI-Suite, KOWWIN v1.68)
- Executive summary:
The substance estimated log octanol-water partition coefficient (Log Kow) is 1.20 (EPI-Suite, KOWWIN v1.68)
- Endpoint:
- partition coefficient
- Type of information:
- (Q)SAR
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
- Remarks:
- Internationally accepted method, EPI-Suite, EPA (USA)
- Justification for type of information:
- See attached the QMRF and QPRF for the QSAR model
- Guideline:
- other: REACH Guidance on QSARs R.6
- Principles of method if other than guideline:
- Meylan, W.M. and P.H. Howard. 1995. Atom/fragment contribution method for estimating octanol water partition coefficients. J. Pharm. Sci. 84: 83-92.
- Specific details on test material used for the study:
- SMILES: CO[Si](C)(O)OC
- Type:
- log Pow
- Partition coefficient:
- -1.37
- Remarks on result:
- other: QSAR predicted value
- Conclusions:
- The estimated log octanol-water partition coefficient (Log Kow) is -1.37 (EPI-Suite, KOWWIN v1.68)
- Executive summary:
The substance estimated log octanol-water partition coefficient (Log Kow) is -1.37 (EPI-Suite, KOWWIN v1.68)
- Endpoint:
- partition coefficient
- Type of information:
- (Q)SAR
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
- Remarks:
- Internationally accepted method, EPI-Suite, EPA (USA)
- Justification for type of information:
- See attached the QMRF and QPRF for the QSAR model
- Guideline:
- other: REACH Guidance on QSARs R.6
- Principles of method if other than guideline:
- Meylan, W.M. and P.H. Howard. 1995. Atom/fragment contribution method for estimating octanol water partition coefficients. J. Pharm. Sci. 84: 83-92.
- Specific details on test material used for the study:
- SMILES: CO[Si](C)(O)O
- Type:
- log Pow
- Partition coefficient:
- -1.66
- Remarks on result:
- other: QSAR predicted value
- Conclusions:
- The estimated log octanol-water partition coefficient (Log Kow) is -1.66 (EPI-Suite, KOWWIN v1.68)
- Executive summary:
The substance estimated log octanol-water partition coefficient (Log Kow) is -1.66 (EPI-Suite, KOWWIN v1.68)
- Endpoint:
- partition coefficient
- Type of information:
- (Q)SAR
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
- Remarks:
- Internationally accepted method, EPI-Suite, EPA (USA)
- Justification for type of information:
- See attached the QMRF and QPRF for the QSAR model.
- Guideline:
- other: REACH Guidance on QSARs R.6
- Principles of method if other than guideline:
- Meylan, W.M. and P.H. Howard. 1995. Atom/fragment contribution method for estimating octanol water partition coefficients. J. Pharm. Sci. 84: 83-92.
- Specific details on test material used for the study:
- SMILES: [Si](O)(O)(O)C
- Type:
- log Pow
- Partition coefficient:
- -2.36
- Remarks on result:
- other: QSAR predicted value
- Conclusions:
- The estimated log octanol-water partition coefficient (Log Kow) is -2.36 (EPI-Suite, KOWWIN v1.68)
- Executive summary:
The substance estimated log octanol-water partition coefficient (Log Kow) is -2.36 (EPI-Suite, KOWWIN v1.68)
Referenceopen allclose all
The guidelines include two separate methods: the shake flask method and high performance liquid chromatography (HPLC).
An experimental determination of the partition coefficient could not be performed, because
1) the test substance rapidly degrades with a half-life time of <1 hour at 25°C, see separate report on the hydrolysis
2) the test substance is a mixture of several compounds for which the shake-flask method is not applicable.
3) the test substance reacts with water (eluent), and in this case the HPLC method is not applicable.
KOWWIN predicted that the test substance has a log Kow of 1.20.
Description of key information
The Log Kow of test item should be understood based on its degradation products since it undergoes rapid hydrolysis (half-life < 1h) in water to acetone oxime (log Kow = 1.20, KOWWIN v1.68) and silanols (Log Kow between -1.37 and -2.36, KOWWIN v1.68).
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 1.2
Additional information
Data waiving (study technically not feasible): According to Column 2 of REACH Annex VII, the study cannot be conducted since the substance undergoes rapid hydrolysis (half-life < 1h) in water to acetone oxime and corresponding silanols. Morevoer, these silanols, i.e. dimethoxymethylsilanol, methoxymethylsilanediol and methylsilanetriol, undergo continuous condensation reactions to produce higher molecular weight siloxanes which are considered biologically unavailable.
The estimated log octanol-water partition coefficients (Log Kow) for the degradation products acetone oxime and silanols were 1.20 and between -1.37 and -2.36 (EPI-Suite, KOWWIN v1.68), respectively. Moreover, according to Jaros et al (2007) the Log Kow of acetone oxime was reported to be 0.20.
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