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EC number: 407-950-9 | CAS number: 895-85-2 INTEROX-PMBP-70W; INTEROX-PMPB-70W
Partition coefficient
Administrative data
Link to relevant study record(s)
- Endpoint:
- partition coefficient
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- September 19-20, 1991
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: Well conducted GLP study, according to OECD guideline 117, purity mentioned.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
- Version / remarks:
- adopted March 30, 1989.
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Type of method:
- HPLC method
- Partition coefficient type:
- octanol-water
- Type:
- log Pow
- Partition coefficient:
- < 0
- Temp.:
- 20 °C
- Remarks on result:
- other: impurity
- Type:
- log Pow
- Partition coefficient:
- 2.4
- Temp.:
- 20 °C
- Remarks on result:
- other: impurity
- Type:
- log Pow
- Partition coefficient:
- 4.7
- Temp.:
- 20 °C
- Remarks on result:
- other: major component
- Conclusions:
- The partition coefficient of bis(4-methylbenzoyl)peroxide is log Pow < 0; log Pow= 2.4 and log Pow = 4.7 for the first (impurity), second (impurity) and third (major component) peak, respectively.
- Executive summary:
The determination of the partition coefficient (n-octanol/water) was based on the OECD Guideline no. 117: "Partition Coefficient (n-octanol/water) High Performance Liquid Chromatographic (HPLC) method" (1989).
In the HPLC chromatograms of DI-(4-METHYLBENZOYL)-PEROXID (INTEROX-PMBP), using UV detection at 210 nm, one large and two small peaks were observed.
It was assumed that the large peak derived from the major component of the test substance whereas the small peaks derived from impurities.
The partition coefficient of bis(4-methylbenzoyl)peroxide is log Pow < 0; log Pow= 2.4 and log Pow = 4.7 for the first (impurity), second (impurity) and third (major component) peak, respectively.
Reference
Representative HPLC chromatograms of the test solution, the mixture of reference substances, the blank and the formamide solution are shown in Figures 1 to 4 in the attachment .
No significant differences were observed between the chromatograms of thetest solution detected at 245 nm and 210 nm (chromatograms not shown). In both chromatograms, no peaks were observed between approximately 18 and 60minutes. Because the mixture of reference substances, the blank and the formamide solution were detected at 210 nm, the chromatogram of the test solution, recorded at 245 nm, was not used for calculations.
The chromatograms of the blank solution, recorded on September 19, did not show any peaks with the same retention as the test substance. However, in the first chromatogram a peak at 34 minutes was observed and in the second chromatogram a peak at 15 minutes was observed. Considering the sequence in which the solutions were injected, it is not very likely that these peaks derived from earlier injections of the test solution, the mixture of reference substances or the formamide solution. In the chromatograms of the blank solution, the mixture of reference substances and the test solution, recorded on September 20, no such peaks were observed. Based on these results it was concluded that these peaks derived from impurities of the HPLC system.
In the HPLC chromatograms of DI-(4-METHYLBENZOYL)-PEROXID (INTEROX-PMBP), using UV detection at 210 nm, one large and two small peaks were observed. It was assumed that the large peak derived from the major component of the test substance whereas the small peaks derived from impurities. The t0was determined to be 1.19 minutes as a mean value of both measurements (individual values not shown). The mean values of the retention times, k' values, log k' values and log Powvalues are summarized in Table 1, see illustration.
In conclusion, the Powvalue for the components of DI-(4-METHYLBENZOYL)PEROXID (INTEROX-PMBP), detectable with the chromatographic system used, were calculated to be < 1 (log Pow= < 0), 2.5xl02(log Pow= 2.4) and 5.0xl04(log Pow = 4.7) for the first (impurity), second (impurity) and third (major component) peak, respectively.
The temperature of the mobile phase was 23.9-24.8°C during the measurements.
Description of key information
The partition coefficient of bis(4-methylbenzoyl)peroxide log Pow = 4.7
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 4.7
- at the temperature of:
- 20 °C
Additional information
The substance rapidly hydrolyzes and the log Kow value of the hydrolysis product p-toluic acid is 2.44
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