Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Deviations:

no

Principles of method if other than guideline:

For two reference substances, log Pow values used in the data evaluation are different from the log Pow values of OECD TG 117 (fluoranthene and DDT). Re-evaluation using the log Pow values of OECD TG 117 result in slightly different log Pow values. These are presented in addition to the original values under results.

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

- Name of test material (as cited in study report): Novares LA 300, Phenol, methylstyrenated [CAS no. 68512-30-1]
- Lot/batch No.: 28166
- Production date: 2009-02-31
- Expiration date of the batch: 2011-12-31
- Composition of test material: composition is specified in IUCLID Sect. 13 - Assessment reports under Certificate of Analysis_Novares LA 300_phenol, methylstyrenated
- Stability under test conditions: water, ethanol acetone, acetonitril, dimethylsulfoxid: 96h
- Storage condition of test material: Room temperature (20 ± 5 °C)

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

3.67

Temp.:

25 °C

pH:

5.5

Remarks on result:

other: sd: ± 0.007; Peak 1 (14 %) (corrected value: 3.73, see below)

Key result

Type:

log Pow

Partition coefficient:

5.96

Temp.:

25 °C

pH:

5.5

Remarks on result:

other: sd: ± 0.005; Peak 4 (37.8 %) (corrected value: 6.15, see below)

Key result

Type:

log Pow

Partition coefficient:

6.15

Temp.:

25 °C

pH:

5.5

Remarks on result:

other: sd: ± 0.004; Peak 5 (25.9 %) (corrected value: 6.35, see below)

Key result

Type:

log Pow

Partition coefficient:

6.3

Temp.:

25 °C

pH:

5.5

Remarks on result:

other: sd: ± 0.004 / considered valid; Peak 7 (21 %) (corrected value: 6.51, see below)

Details on results:

The values listed in the table below are the mean ± standard deviation of three independent determinations. The last small and large peak (peaks 6 and 7) lay outside the range of the method. According to the institute, the log Pows of these peaks 6 and 7 should be stated as > 6.2. As peak 2, 3, and 6 showed a relative area < 5%, they were considered as minor peaks.
Although area is not necessarily correlated to absolute concentration if a UV detector is used, it is supposed that the test item Novares LA 300 consists mainly of the peaks 1, 4, 5, and 7. Taking into account all four major peaks, a range of log Pow values between 3.672 and 6.297 was determined (maximum of range is extrapolated; no reference item with log Pow > 6.2 is mentioned in the guideline). The peaks 4, 5, and 7 have to be considered relevant for the target substance 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised'.

Tables are excerpts from the original report.

The chromatogram of the test item revealed seven peaks: four large and three small peaks (see Attached Document).

With the calibration function log K versus log P_OW, the corresponding log P_OWs were determined with:

Peak	Mean Area [mAU*min]	Rel. Area %	Mean retention time [min]	Log Pow + sd
1	85.3807	14.02	5.701	3.672 ± 0.007
2	1.7543	0.29	6.812	3.945 ± 0.007
3	2.1134	0.35	26.470	5.750 ± 0.006
4	230.2626	37.82	31.317	5.957 ± 0.005
5	157.9556	25.94	36.555	6.145 ± 0.004
6	2.3566	0.39	39.590	6.242 ± 0.004
7	127.5514	20.95	41.419	6.297 ± 0.004

Table 9.1‑a           Retention times of reference items

Compound	RT1	RT2	RT3	RT4	RT5	RT6
	min.	min.	min.	min.	min.	min.
Thio urea	1.502	1.502	1.499	1.503	1.503	1.504
Acetophenone	2.259	2.263	2.263	2.266	2.265	2.266
Naphthalene	5.394	5.406	5.441	5.441	5.415	5.440
Diphenylether	7.183	7.204	7.262	7.275	7.217	7.262
Phenanthrene	10.176	10.201	10.294	10.325	10.243	10.301
Fluoranthene	14.084	14.137	14.251	14.330	14.196	14.289
Triphenylamine	24.813	24.954	25.200	25.379	25.061	25.250
DDT	35.215	35.491	35.882	35.958	35.679	35.939

Table 9.1‑b           Capacity factors (K) of reference items

Compound	Retention Time Mean	Retention Time Stand. Dev.	Retention Time Relative Stand. Dev.	K
	min.	min.	%
Thio urea	1.502*	0.002	0.115	-
Acetophenone	2.264	0.003	0.117	0.5069
Naphthalene	5.423	0.021	0.381	2.6100
Diphenylether	7.234	0.038	0.519	3.8156
Phenanthrene	10.257	0.060	0.582	5.8279
Fluoranthene	14.215	0.093	0.657	8.4627
Triphenylamine	25.110	0.207	0.826	15.7155
DDT	35.694	0.295	0.827	22.7617

* Dead time is 1.502 ± 0.002 minutes, with RSD 0.115 %.

Table 9.1‑c           

Log K and log P_OW of reference items

Compound	log K	log POW
Acetophenone	-0.2950	1.70
Naphthalene	0.4166	3.60
Diphenylether	0.5816	4.20
Phenanthrene	0.7655	4.50
Fluoranthene	0.9275	4.70
Triphenylamine	1.1963	5.70
DDT	1.3572	6.20

Log Pow of fluoranthene and DDT presented in Table 9.1-c differ from the values given in OECD TG 117 (5.1 and 6.5, respectively). Re-analysis of data based on log Pow values given in the OECD TG results in slighly different log Pow values extending to somewhat higher values (peak 1: 3.732; peak 4: 6.147; peak 5: 6.346; peak 7: 6.506). After correction, the highest log Pow value determined does not exceed the range of reference log Pow values.

Conclusions:

The result of Peak 7 can be considered as valid, although the range of calibration did not include the retention time (RT) of Peak 7 at the upper end of the calibration curve (see Attached Document). The small difference in the retention time(RT) between Peak 7 and the reference standard (DDT) with the highest RT (41.4 min vs. 35.7 min) allows extrapolation without substantial error.
The test method did not allow to identify the individual peaks. It is assumed that log Pow of 6.3 represents only the components 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised' with the corresponding lipophilic characteristics of the mixture (dimers of the substance) (see other study records "Calculation log Kow" and EP Summary/Discussion).

Reference 2

Endpoint:

partition coefficient

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The source test material ‘Oligomerisation and alkylation reaction products of 2-phenylpropene and phenol (OAPP) [EC no. 700-960-7] consists of a complex mixture of numerous aryl-aromatic constituents some of them containing also a phenolic structural element. The constituents can basically be divided into groups corresponding to the presence of phenolic OH-groups as well as their level of oligomerisation (dimers, trimers).
The target substance ‘Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised’ (NAF-AO) [EC no. 701-299-207] consists also of a complex mixture of numerous aryl-aromatic constituents but without phenolic substituents present. Its components can basically be divided into groups corresponding to their level of oligomerisation (dimers, trimers, tetramers).
Both substances have various constituents in common (non-phenolic dimers, trimers and tetramers / higher oligomers). In the method used for the determination of log Pow values, individual constituents(/constituent groups are determined independently. Therefore, the source substance OAPP is suited as supporting substance for NAF-AO in the investigation of the octanol/water partition properties of the target substance NAF-AO.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The source substance OAPP is a UVCP substance obtained in an acid catalysed oligomerisation / alkylation reaction of the starting materials 2-phenylpropene and phenol. In this process, aromatic and phenolic components react with each other resulting on the one hand in oligomerisation products of 2-phenylpropene (reaction of 2-phenylpropene molecules among themselves, aryl-aliphatic substances) and on the other hand in 2-phenylprop-2-yl substituted (methylstyrenated) phenols (reaction of 2-phenylpropene with phenol, aralkyl-substituted phenols, phenolic substances). Besides dimeric products also trimeric and oligomeric products can be formed. Aromatic rings within the products are connected by methyl-substituted alkenyl carbon-chains in case of the 2-phenylpropene oligomers and by a single bridging carbon atom substituted by two methyl groups in case of methylstyrenated phenols. Besides phenyl substituents, non-phenolic oligomers of OAPP can also include indane substituents.
Based on the degree of oligomerisation four to five basic groups of constituents are formed. Two or three groups contain purely aryl-aliphatic (non-phenolic) substances differing only in the degree of oligomerisation (dimers, trimers, and higher (n ≥ 4) oligomers). Two groups comprise the alkylation products of phenol (mono or di 2-phenylprop-2-yl (methylstyryl) substituted phenols; phenolic products). Non-phenolic constituents (aryl-aliphatic oligomers) amount together to about 45 to 80% of OAPP, while the phenolic components contribute about 20 to 50%.
OAPP is a viscous oily material with a low water solubility (between 1 and 3.5 mg/L depending on its composition).
The target substance NAF-AO is a UVCB substance as well, also obtained in an acid catalysed alkylation and oligomerisation reaction of the starting material ‘Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction’. This material comprises predominantly styrene and indene derivatives. In the production process, oligomerisation products of C8-10 aromatic hydrocarbons are formed consisting of dimeric, trimeric, and oligomeric (n ≥ 4) products. The individual constituents are the same as are produced in the production process of OAPP. Due to the composition of the starting material, no phenolic but only aryl-aliphatic products are formed. These products consist of two, three, or more aromatic rings connected by methyl-substituted alkenyl carbon-chains (dimers, trimers, oligomers). The aromatic substituents include besides benzene also indane. Based on the degree of oligomerisation, constituents are combined into three different groups (dimers, trimers and higher oligomers). Depending on the type of technical product (Novares L 100, L 700, TL 10), composition with respect to different component groups will vary (dimers from ca. 20 to 70%, trimers from ca. 10 to 30%, higher oligomers from ca. 15 to 50%).
NAF-AO is a viscous oily material with a low water solubility (between 0.6 and 1.3 mg/L depending on its composition). Thus, water solubility is somewhat lower than the water solubility of OAPP. Values for water solubility obtained by (Q)SAR (US EPA EPI suite) for individual model constituents are lower (between 0.082 and 0.038 mg/L for dimers and between 0.011 and 0.027 mg/L for trimers) indicating that measured values may overestimate the real water solubility. Overall, the water solubility of NAF-AO is low to very low depending on the technical product and its composition (higher percentages of trimers and higher oligomers will reduce the water solubility).

3. ANALOGUE APPROACH JUSTIFICATION
Source and target substance are to an essential part composed of the same constituents (aryl-aliphatic substances - dimers, trimers). The test method (HPLC method) will provide distinct data for individual components present in a test material. Results for identical components will coincide even if the components are part of different test materials. For this reason, it is justified to use data determined for the source substance OAPP to characterise octanol-water partitioniing of the target substance NAF-AO.


4. DATA MATRIX

Reason / purpose for cross-reference:

read-across source

Principles of method if other than guideline:

Read-across to preceding entry:
Source test material: Oligomerisation and alkylation reaction products of 2-phenylpropene and phenol;
Reference: Henke 2010

Key result

Type:

log Pow

Partition coefficient:

3.73

Temp.:

25 °C

pH:

5.5

Remarks on result:

other: corrected value for peak 1 (14%); the original study result is 3.67 ± 0.007

Remarks:

the test result of the source substance is adopted for the target substance NAF-AO

Key result

Type:

log Pow

Partition coefficient:

6.15

Temp.:

25 °C

pH:

5.5

Remarks on result:

other: corrected value for peak 4 (37.8%); the original study result: is 5.96 ± 0.005

Remarks:

the test result of the source substance is adopted for the target substance NAF-AO

Key result

Type:

log Pow

Partition coefficient:

6.35

Temp.:

25 °C

pH:

5.5

Remarks on result:

other: corrected value for peak 5 (25.9%); the original study result is 6.15 ± 0.004

Remarks:

the test result of the source substance is adopted for the target substance NAF-AO

Key result

Type:

log Pow

Partition coefficient:

6.51

Temp.:

25 °C

pH:

5.5

Remarks on result:

other: corrected value for peak 7 (21%); the original study result is 6.3 ± 0.004

Remarks:

the test result of the source substance is adopted for the target substance NAF-AO

Details on results:

A justification for the correction of study results is given in the read across source and in the endpoint summary.

Reference 3

Endpoint:

partition coefficient

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

1. SOFTWARE
US EPA (2012 ). Estimation Programs Interface Suite™ (EPI Suite) for Microsoft® Windows, v 4.11. United States Environmental Protection Agency, Washington, DC, USA.

2. MODEL (incl. version number)
Model KOWWIN, version 1.68

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CAS 3910-35-8: c(c(ccc1)C(C2)(C)C)(c1)C2(c(cccc3)c3)C (ECHA's Reference Substance SMILES notation "CC1(C)CC(C)(c2ccccc2)c3ccccc13" results in the same structure)
CAS 6362-80-7: c(cccc1)(c1)C(CC(c(cccc2)c2)=C)(C)C (ECHA's Reference Substance SMILES notation "CC(C)(CC(=C)c1ccccc1)c2ccccc2" results in the same structure)
CAS 6258-73-7: c(cccc1)(c1)C(C=C(c(cccc2)c2)C)(C)C (ECHAs Reference Substance SMILES notation "CC(C)(C=C(C)c1ccccc1)c2ccccc2" results in the same structure)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: yes, log Kow
- Unambiguous algorithm: yes
- Defined domain of applicability: see under Attached justification

5. APPLICABILITY DOMAIN
- Descriptor domain: specified by molecular fragments
- Similarity with analogues in the training set: yes
- Other considerations: for more detailed information see under Attached justification

6. ADEQUACY OF THE RESULT
Result of the prediction is used as information for the dimeric constituents (dimers of C8-10 aromatic fraction) of the registration substance 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised' and as weight of evidence information on the log Kow of the substance.

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Software tool(s) used including version: US EPA (2012 ). Estimation Programs Interface Suite™ (EPI Suite) for Microsoft® Windows, v 4.11. United States Environmental Protection Agency, Washington, DC, USA.
- Model(s) used: Model KOWWIN, version 1.68
- Model description: see field 'Justification for non-standard information' and 'Attached justification'
- Justification of QSAR prediction: see field 'Justification for type of information' and 'Attached justification'
Log Pow values of three different compounds were calculated that are constituents of the dimeric components of 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised'

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Analytical method:

other: not applicable

Key result

Type:

log Pow

Partition coefficient:

5.91

Remarks on result:

other: substance 1,1,3-trimethyl-3-phenylindan, calculated value

Key result

Type:

log Pow

Partition coefficient:

6.512

Remarks on result:

other: substance 1,1'-(1,1-dimethyl-3-methylene-1,3-propanediyl)bisbenzene (CAS no. 6362-80-7), calculated value

Key result

Type:

log Pow

Partition coefficient:

6.434

Remarks on result:

other: substance 1,1'-(1,3,3-trimethylprop-1-ene-1,3-diyl)dibenzene (CAS no. 6258-72-7), calculated value

Conclusions:

The substance 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised' (NAF-AO) consists basically of three components: dimers, trimers, and oligomers of the starting material C8-10 aromatic hydrocarbon fraction. Due to similar size and related structures, partition coefficients (log Kow) within one group differ only to a small extent. For dimers, log Kow values (estimated with the program KOWWIN) range from 5.91 to 6.51. This difference is much smaller that the log Kow difference between the group of dimers, trimers and oligomers (ca. 6 - 6.5, ca. 9 - 9.6, and even higer, respectively). In combination these values characterise the distribution characteristics of NAF-OH.

Reference 4

Endpoint:

partition coefficient

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

1. SOFTWARE
US EPA (2012 ). Estimation Programs Interface Suite™ (EPI Suite) for Microsoft® Windows, v 4.11. United States Environmental Protection Agency, Washington, DC, USA.

2. MODEL (incl. version number)
Model KOWWIN, version 1.68

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CAS 41906-71-2: c(c(ccc1)C(C2)(CC(c(cccc3)c3)(C)C)C)(c1)C2(c(cccc4)c4)C (ECHA's Reference Substance SMILES notation "CC(C)(CC1(C)CC(C)(c2ccccc2)c3ccccc13)c4ccccc4" results in the same structure)
CAS 62604-62-0: c(cccc1)(c1)C(CC(c(cccc2)c2)(CC(c(cccc3)c3)=C)C)(C)C (ECHA's Reference Substance SMILES notation "CC(C)(CC(C)(CC(=C)c1ccccc1)c2ccccc2)c3ccccc3" results in the same structure)
CAS 19303-34-5: c(cccc1)(c1)C(C=C(c(cccc2)c2)C)(CC(c(cccc3)c3)(C)C)C (ECHAs Reference Substance SMILES notation "CC(C)(CC(C)(C=C(C)c1ccccc1)c2ccccc2)c3ccccc3" results in the same structure)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: yes, log Kow
- Unambiguous algorithm: yes
- Defined domain of applicability: see under Attached justification

5. APPLICABILITY DOMAIN
- Descriptor domain: specified by molecular fragments
- Similarity with analogues in the training set: yes
- Other considerations: for more detailed information see under Attached justification

6. ADEQUACY OF THE RESULT
Result of the prediction is used as information for the dimeric constituents (dimers of C8-10 aromatic fraction) of the registration substance 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised' and as weight of evidence information on the log Kow of the substance.

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Software tool(s) used including version: US EPA (2012 ). Estimation Programs Interface Suite™ (EPI Suite) for Microsoft® Windows, v 4.11. United States Environmental Protection Agency, Washington, DC, USA.
- Model(s) used: Model KOWWIN, version 1.68
- Model description: see field 'Justification for non-standard information' and 'Attached justification'
- Justification of QSAR prediction: see field 'Justification for type of information' and 'Attached justification'
Log Pow values of three different compounds were calculated that are constituents of the trimeric components of 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised'

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Analytical method:

other: not applicable

Key result

Type:

log Pow

Partition coefficient:

8.98

Remarks on result:

other: substance 1,3-dimethyl-1-(2-methyl-2-phenylpropyl)-3-phenylindan, calculated value

Key result

Type:

log Pow

Partition coefficient:

9.58

Remarks on result:

other: substance 1,1',1''-(1,1,3-trimethyl-5-methylenepentane-1,3,5-triyl)tribenzene, calculated value

Key result

Type:

log Pow

Partition coefficient:

9.5

Remarks on result:

other: substance 1,1',1''-(1,3,5,5-tetramethylpent-1-ene-1,3,5-triyl)tribenzene, calculated value

Conclusions:

The substance 'Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised' (NAF-AO) consists basically of three components: dimers, trimers, and oligomers of the starting material C8-10 aromatic hydrocarbon fraction. Due to similar size and related structures, partition coefficients (log Kow) within one group differ only to a small extent. For trimers, log Kow values (estimated with the program KOWWIN) range from 8.96 to 9.58. This difference is much smaller than the log Kow difference between the group of dimers, trimers and oligomers (ca. 6 - 6.5, ca. 9 - 9.6, and even higer, respectively). In combination these values characterise the distribution characteristics of NAF-OH.

Description of key information

The three main components of the substance ‘Naphtha (petroleum), steam-cracked, C8-10 aromatic hydrocarbon fraction, alkylated and oligomerised’ (NAF-AO) (Novares L-series) (see Chapter 1) comprise dimers, trimers, and higher (n ≥ 4) oligomers of the C8-10 monomeric aromatic hydrocarbon fraction. For each of these groups of components, there is a characteristic range of log Pow values (around 6.4, around 9.5, and higher for oligomers) estimated for individual components by (Q)SAR calculation.

The structure related substance 'Oligomerisation and alkylation reaction products of 2-phenylpropene and phenol' (OAPP) (Novares LA-series) contains besides phenolic constituents also dimers and trimers of the C8-10 aromatic hydrocarbon fraction. In a study using the HPLC method (OECD TG 117), maximum log Pows between ca. 6.1 and 6.5 have been determined (dimeric components). Higher log Pow values are out of the range of this method.

Key value for chemical safety assessment

Log Kow (Log Pow):

9.5

at the temperature of:

25 °C

Additional information

An experimental study on the partition coefficient (n-octanol / water) of the substance NAF-AO is not available. In a first approximation, log Pow values have been estimated for constituents of the dimeric and trimeric components of NAF-AO using the program US EPA EPI Suite, model component KOWWIN. The result are presented in the following table.

 

Log Pow values of dimeric and trimeric constituents of NAF-AO (KOWWIN estimates)

Substance	CAS no.	log Pow
Dimers
1,1,3-Trimethyl-3-phenylindan	3910-35-8	5.9094
1,1’-(1,1-Dimethyl-3-methylene-1,3-propanediyl)bisbenzene	6362-80-7	6.5123
1,1’-(1,3,3-Trimethylprop-1-ene-1,3-diyl)dibenzene	6258-73-7	6.4337
Trimers
1,3-dimethyl-1-(2-methyl-2-phenylpropyl)-3-phenylindan	41906-71-2	8.9794
1,1',1''-(1,1,3-trimethyl-5-methylenepentane-1,3,5-triyl)tribenzene	62604-62-0	9.5823
1,1',1''-(1,3,5,5-tetramethylpent-1-ene-1,3,5-triyl)tribenzene	19303-34-5	9.5037

 

Due to the structure and molecular size of constituents, two ranges of log Pow values can be specified. For dimers, log Pow range from ca. 5.9 to ca. 6.5. Log Pow values of trimers extend from ca. 9 to ca. 9.6. For higher oligomers (n ≥ 4), individual compounds/structures are not known. Therefore, a log Pow could not be determined. But it is estimated that log Pow values are even higher in a range from above 10 to 11.

 

As second approach, read-across to the substance OAPP is used. The source substance OAPP (supporting substance) contains besides other constituents the same dimeric and trimeric constituents as the target substance NAF-AO.

 

In a GLP study according to OECD TG 117 (Partition Coefficient (n-octanol/water), HPLC Method), a log Pow profile has been derived for the source substance OAPP (LA300 ('LA-series')). Four major peaks with areas distinctly higher than 5 % could be detected. The area sum of these peaks accounts for some 85 % under analytical test conditions. Direct substance identification of different peaks is not possible. But PEAK 1 is likely to represent 4-cumylphenol [CAS no. 599-64-4], based on the lowest log Pow. The other peaks are assumed to represent 2,4-dicumylphenol [CAS no. 2772-45-4] (log Pow US EPA EPI Suite estimate is 6.73) and dimers. Log Pow values of trimers cannot be determined under the conditions of the test (chromatographic conditions are adjusted to the highest reference log Pow of 6.5 for DDT).

In the original data evaluation, log Pow values of two reference substance were different from the log Pow values given in the test guideline. Guideline conform re-evaluation resulted in the corrected log Pow values presented below.

 

Substantial peaks (area > 5 %) in the HPLC-chromatogram and related log Pow values

HPLC/UV	PEAK 1	PEAK 4	PEAK 5	PEAK 7
Area (%*)	14	38	26	21
Log Pow*	3.67	5.95	6.15	6.3
Log Pow (corrected)*	3.73	6.15	6.35	6.51

*Values rounded

 

Considering the composition of NAF-AO, a representative log Pow has to take into account also the trimers and higher oligomers. As average, a log Pow value of 9.5 is considered to be representative of the substance as such.