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Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
November 27th, 2012 - April 7th, 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
Version / remarks:
(2008)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Version / remarks:
(2001)
Deviations:
no
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
soil
Radiolabelling:
no
Details on study design: HPLC method:
CALCULATION OF pKa:
The following pKa values in the pH range of 1 - 14 were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, USA):

2,2’-[(4-methylphenyl)imino]-diethanol: acidic (none); basic: RARN(R1R2): pKa 4.02
2-{[2-(2-hydroxyethoxy)ethyl](4-methylphenyl)amino}ethanol: acidic (none); basic: RARN(R1R2): pKa 3.94

HPLC METHOD CONDITIONS:
Instrument: Acquity UPLC system (Waters, Milford, MA, USA)
Detector: Acquity UPLC TUV detector (Waters)
Column: Acquity UPLC HSS, 50 mm x 2.1 mm i.d., dp = 1.8 µm (Waters)
Column temperature: 35°C ± 1°C
Mobile phase: 30/70 (v/v) methanol/water
Flow : 0.4 mL/min
Injection volume: 5 μL
UV detection: 210 nm

REFERENCE SUBSTANCES: acetanilide; Monuron; 2,5-dichloroaniline; benzoic acid phenylester and Fenthion
Unretained compound: Formamide
 
PREPARATION OF SOLUTIONS:
Solution of the unretained compound
A 5.22 g/L stock solution of formamide in methanol was used. The stock solution was diluted to obtain an end solution of 30/70 (v/v) methanol/water. The formamide blank solution was 30/70 (v/v) methanol/water.

Reference substance solutions
Stock solutions of the reference substances at concentrations of approximately 1 g/L in methanol were used. The stock solutions were diluted to obtain an end solution of 30/70 (v/v) methanol/water. The blank solution for the reference substance solutions was 30/70 (v/v) methanol/water.

Test solution
A 2180 mg/L stock solution of the test substance was prepared in methanol. The stock solution was diluted to obtain an end solution of 30/70 (v/v) methanol/water. The final concentration of the test substance solution was 9.98 mg/L. The test substance blank solution was 30/70 (v/v) methanol/water.

The reference substance and test substance solutions were injected in duplicate. Blank solutions were analysed by single injection.

PERFORMANCE OF THE STUDY
Solutions of reference substances with known log Koc values based on soil adsorption data and the test substance were analysed. The capacity factor (k') of each compound was calculated from its retention time. The log k’ values of the references substances were plotted against the known log Koc values. A linear regression program was used to calculate the calibration curve. Linear regression analysis was performed using the least squares method. The coefficient of correlation (r) was calculated. The log Koc value for the test substance was calculated by substituting its mean log k’ in the calibration curve: log k’ = 0.709 x log Koc – 0.978 (r = 0.94, n = 12). The value of log Koc obtained from duplicate measurements was within ± 0.25 log units.
Analytical monitoring:
yes
Type:
log Koc
Value:
2.22 dimensionless
Temp.:
35 °C
Remarks on result:
other: Peak area 52%
Type:
log Koc
Value:
2.44 dimensionless
Temp.:
35 °C
Remarks on result:
other: Peak area 38%
Type:
log Koc
Value:
2.51 dimensionless
Temp.:
35 °C
Remarks on result:
other: Peak area 4.9%
Type:
log Koc
Value:
2.67 dimensionless
Temp.:
35 °C
Remarks on result:
other: Peak area 2.4%
Key result
Type:
log Koc
Value:
2.33 dimensionless
Temp.:
20 °C
Remarks on result:
other: weight-averaged value based on four main components covering 97.3% (by area-%) of the whole substance (Koc = 214)
Details on results (HPLC method):
In the HPLC chromatogram of the test substance, a total number of 18 peaks have been identified from which four peaks with retention times of 3.47 min. (52% peak area), 4.65 min. (38% peak area), 5.17 min. (4.9% peak area) and 6.46 min. (2.4% peak area) were observed. Under the same conditions, the retention time of benzoic acid phenylester (log Koc 2.87) was 10.55 - 10.53 minutes.
Transformation products:
not measured

Table: Measurements and results for the Koc determination:

Substance

mean tr
(n=2)

log Koc

Koc

Area
%

 

 

 

 

 

Formamide (t0)

0.703

 

 

 

 

 

 

 

 

Acetanilide

 

1.26

 

 

Monuron

 

1.99

 

 

2,5-Dichloroaniline

 

2.55

 

 

Naphthalene

 

2.75

 

 

Benzoic acid phenylester

 

2.87

 

 

Fenthion

 

3.31

 

 

 

 

 

 

 

peak 1

1.316

1.30

2.0´101

0.032

peak 2

1.571

1.51

3.2´101

0.30

peak 3

1.836

1.67

4.7´101

0.85

peak 4

2.237

1.86

7.2´101

0.44

peak 5

2.366

1.91

8.1´101

0.060

peak 6

2.614

1.99

9.8´101

0.012

peak 7

2.781

2.04

1.1´102

0.021

peak 8

3.285

2.18

1.5´102

0.0054

peak 9

3.469

2.22

1.7´102

52

peak 10

4.647

2.44

2.7´102

38

peak 11

5.174

2.51

3.2´102

4.9

peak 12

6.035

2.62

4.2´102

0.058

peak 13

6.271

2.65

4.4´102

0.046

peak 14

6.464

2.67

4.6´102

2.4

peak 15

7.104

2.73

5.4´102

0.36

peak 16

9.456

2.92

8.4´102

0.024

peak 17

9.583

2.93

8.6´102

0.084

peak 18

9.926

2.96

9.0´102

0.058

 

 

 

 

 

Validity criteria fulfilled:
yes
Conclusions:
The HPLC method (in accordance with EC C.19 and OECD 121 and in compliance with GLP) was performed to determine the adsorption coefficient (soil) of the test substance. The HPLC chromatogram of the test solution showed four major peaks (with peak areas of 52%, 38%, 4.9% and 2.4%). The log Koc for the major peaks were 2.22, 2.44, 2.51 and 2.67, respectively. The weight-averaged logKoc value considering the four main components has been derived to be 2.33 (= log 214). HPLC column temperature: 35°C ± 1°C, but the log Koc of reference substances have been determined at 20 °C, thus the 2.33 value is determined as well for 20 °C.
Endpoint:
adsorption / desorption: screening
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: read-across from a structural analogue
Justification for type of information:
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The substance Accelerator (Reaction mass of 2,2'-[(4-methylphenyl)imino]bisethanol and 2-[[2-(2-hydroxyethoxy)ethyl](4-methylphenyl)amino]-ethanol)) is a structural analogue of 2,2'-[(3-methylphenyl)imino]bisethanol. Accelerator contains ca. 50-60% of 2,2'-[(4-methylphenyl)imino]bisethanol as the main constituent. The only difference between 2,2'-[(4-methylphenyl)imino]bisethanol and the target chemical 2,2'-[(3-methylphenyl)imino]bisethanol is the position of the methyl group in the phenyl ring (para vs meta with regard to the imino group). This is not expected to have any significant influnce either on physico-chemical properties or on toxicological behavior of the substances. Next to 2,2'-[(4-methylphenyl)imino]bisethanol Accelerator contains ca. 35-45% of 2-{[2-(2-hydroxyethoxy)ethyl](4-methylphenyl)amino}ethanol, which contains the same structural moiety of 2,2'-[(4-methylphenyl)imino]bisethanol, but with one ethanol moiety transformed into the ester bond with ethylene glycol. As Accelerator contains over 50% of the structural analogue of 2,2'-[(3-methylphenyl)imino]bisethanol, with the only difference being the position of the methyl group in the phenyl ring, it is considered acceptable to read across the results of the adsorption/desorption study from Accelerator to 2,2'-[(3-methylphenyl)imino]bisethanol.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The source chemical is Accelerator (Reaction mass of 2,2'-[(4-methylphenyl)imino]bisethanol and 2-[[2-(2-hydroxyethoxy)ethyl](4-methylphenyl)amino]-ethanol)), containing ca. 50-60% of 2,2'-[(4-methylphenyl)imino]bisethanol, ca. 35-45% of 2-{[2-(2-hydroxyethoxy)ethyl](4-methylphenyl)amino}ethanol and ca. 2-4% of 2-[{2-[2-(2-hydroxyethoxy)ethoxy]ethyl}(4-methylphenyl)amino]ethanol. The purity of the substance is ca. 90-100%.

The target chemical is 2,2'-[(3-methylphenyl)imino]bisethanol with the purity of 90-10%. The substance contains up to 7% 2-{[2-(2-hydroxyethoxy)ethyl](3-methylphenyl)amino}ethanol as an impurity.

3. ANALOGUE APPROACH JUSTIFICATION
The substance Accelerator (Reaction mass of 2,2'-[(4-methylphenyl)imino]bisethanol and 2-[[2-(2-hydroxyethoxy)ethyl](4-methylphenyl)amino]-ethanol)) is a structural analogue of 2,2'-[(3-methylphenyl)imino]bisethanol. Accelerator contains ca. 50-60% of 2,2'-[(4-methylphenyl)imino]bisethanol as the main constituent. The only difference between 2,2'-[(4-methylphenyl)imino]bisethanol and the target chemical 2,2'-[(3-methylphenyl)imino]bisethanol is the position of the methyl group in the phenyl ring (para vs meta with regard to the imino group). As adsorption/desorption coefficient depends on physico-chemical properties of the substance, i.e. octanol-water partition coefficient and water solubility, the difference in the position of the methyl group of the phenyl ring is not expected to have a significant influence on the Koc value. Moreover, in the adsorption/desorption study conducted with Accelerator separate peaks on the chromatogram were identified for different constituents. Based on the peak areas and the composition of the substance, it is possible to identify the peak corresponding to 2,2'-[(4-methylphenyl)imino]bisethanol and thus to read-across the Koc value derived for 2,2'-[(4-methylphenyl)imino]bisethanol to its meta-isomer 2,2'-[(3-methylphenyl)imino]bisethanol.

Furthermore, the data matrix constructed based on the available physico-chemical and (eco)toxicological properties of both substances indicates that the substances have comparable properties across the complete range of endpoints.

Based on this, read-across from Accelerator to 2,2'-[(3-methylphenyl)imino]bisethanol is considered to be justified.

4. DATA MATRIX

Accelerator PT25 2,2'-[(3-methylphenyl)imino]bisethanol

Molecular weight ~217 195.26
State of the substance at ambient conditions Clear slightly yellowish to brown viscous liquid Colourless solidified melt
Melting/freezing point [ºC] Not determined (glass transition temp. of -28ºC) 66.9
Boiling point [ºC] - (decomposition at >275ºC) - (reaction and/or decomposition at > 225°C)
Relative density at 20 ºC 1.11 1.115
Vapour pressure at 25 ºC [Pa] 0.0025 0.000223 (calculated)
Surface tension [mN/m] 65.2 at 1 g/L, not surface active 65.4 at 1 g/L, not surface active
Water solubility at 20 ºC [mg/L] 21800 9330
Partition coefficient n-octanol/water [log Pow] 2.17 1.9
Flash point [ºC] 176 193
Flammability Not flammable, not pyrophoric Not flammable, not pyrophoric
Explosive properties Not explosive Not explosive
Auto-ignition temperature [ºC] 395 395
Oxidising properties Not oxidizing Not oxidizing
Viscosity (dynamic, mPas) 2797 5474
Ready biodegradability Not readily biodegradable Not readily biodegradable
Hydrolysis as function of pH Half-life for hydrolysis >1 y at 25 ºC, hydrolytically stable Read-across
Adsorption/desorption [log Koc] 2.33 (weight-averaged of 4 main components) Read-across (main constituent)
Acute toxicity to daphnia, EC50 [mg/L] 48 107
Growth inhibition algae, EC50, NOEC [mg/L] >100; 100 >100; 100
Acute toxicity to fish, LC50 [mg/L] >100 >102
Acute oral, LD50 [mg/kg bw] 619 300-2000
Skin irritation/corrosion Skin irritant cat 2. Read-across
Eye irritation Corrosive, cat 1. Read-across
Skin sensitisation Sensitiser Read-across
In vitro gene mutation in bacteria (Ames test) Mutagenic Non-mutagenic
In vitro cytogenicity in mammalian cells (CA) Not clastogenic, does not disturb mitotic processes Not clastogenic, does not disturb mitotic processes
In vivo genotox (Comet) Not mutagenic No data
28-day repeated dose toxicity NOAEL 100 mg/kg bw LOAEL 50 mg/kg bw/day
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
Version / remarks:
(2008)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Version / remarks:
(2001)
Deviations:
no
Key result
Type:
log Koc
Value:
2.22 dimensionless
Temp.:
35 °C
Remarks on result:
other: Peak area 52%
Type:
log Koc
Value:
2.44 dimensionless
Temp.:
35 °C
Remarks on result:
other: Peak area 38%
Type:
log Koc
Value:
2.51 dimensionless
Temp.:
35 °C
Remarks on result:
other: Peak area 4.9%
Type:
log Koc
Value:
2.67 dimensionless
Temp.:
35 °C
Remarks on result:
other: Peak area 2.4%
Type:
log Koc
Value:
2.33 dimensionless
Temp.:
20 °C
Remarks on result:
other: weight-averaged value based on four main components covering 97.3% (by area-%) of the whole substance (Koc = 214)
Details on results (HPLC method):
In the HPLC chromatogram of the test substance, a total number of 18 peaks have been identified from which four peaks with retention times of 3.47 min. (52% peak area), 4.65 min. (38% peak area), 5.17 min. (4.9% peak area) and 6.46 min. (2.4% peak area) were observed. Under the same conditions, the retention time of benzoic acid phenylester (log Koc 2.87) was 10.55 - 10.53 minutes.
Transformation products:
not measured

Table: Measurements and results for the Koc determination:

Substance

mean tr
(n=2)

log Koc

Koc

Area
%

 

 

 

 

 

Formamide (t0)

0.703

 

 

 

 

 

 

 

 

Acetanilide

 

1.26

 

 

Monuron

 

1.99

 

 

2,5-Dichloroaniline

 

2.55

 

 

Naphthalene

 

2.75

 

 

Benzoic acid phenylester

 

2.87

 

 

Fenthion

 

3.31

 

 

 

 

 

 

 

peak 1

1.316

1.30

2.0´101

0.032

peak 2

1.571

1.51

3.2´101

0.30

peak 3

1.836

1.67

4.7´101

0.85

peak 4

2.237

1.86

7.2´101

0.44

peak 5

2.366

1.91

8.1´101

0.060

peak 6

2.614

1.99

9.8´101

0.012

peak 7

2.781

2.04

1.1´102

0.021

peak 8

3.285

2.18

1.5´102

0.0054

peak 9

3.469

2.22

1.7´102

52

peak 10

4.647

2.44

2.7´102

38

peak 11

5.174

2.51

3.2´102

4.9

peak 12

6.035

2.62

4.2´102

0.058

peak 13

6.271

2.65

4.4´102

0.046

peak 14

6.464

2.67

4.6´102

2.4

peak 15

7.104

2.73

5.4´102

0.36

peak 16

9.456

2.92

8.4´102

0.024

peak 17

9.583

2.93

8.6´102

0.084

peak 18

9.926

2.96

9.0´102

0.058

 

 

 

 

 

Validity criteria fulfilled:
yes
Conclusions:
In a GLP-compliant guideline study performed with a structural analogue of 2,2'-[(3-methylphenyl)imino]bisethanol, Accelerator, 4 major peaks were identified on the HPLC chromatogram with peak areas of 52%, 38%, 4.9% and 2.4%. As Accelerator contains ca. 50-60% of 2,2'-[(4-methylphenyl)imino]bisethanol, it is feasible to assume that the largest peak on the chromatogram corresponded to 2,2'-[(4-methylphenyl)imino]bisethanol. As 2,2'-[(4-methylphenyl)imino]bisethanol differs from the target chemical 2,2'-[(3-methylphenyl)imino]bisethanol only by the position of the methyl group in the phenyl ring it is possible to read across the log Koc value of 2.22 derived for 2,2'-[(4-methylphenyl)imino]bisethanol to 2,2'-[(3-methylphenyl)imino]bisethanol.
Executive summary:

A study was performed with a structural analogue of 2,2'-[(3-methylphenyl)imino]bisethanol, Accelerator (Reaction mass of 2,2'-[(4-methylphenyl)imino]bisethanol and 2-[[2-(2-hydroxyethoxy)ethyl](4-methylphenyl)amino]-ethanol). The HPLC method (in accordance with EC C.19 and OECD 121 and in compliance with GLP) was used to determine the adsorption coefficient (soil) of the test substance. The  HPLC chromatogram of the test solution showed four major peaks (with peak areas of 52%, 38%, 4.9% and 2.4%). The log Koc values for the major peaks were 2.22, 2.44, 2.51 and 2.67, respectively. Considering that Accelerator contains > 50% of the structural analogue 2,2'-[(4-methylphenyl)imino]bisethanol which differs from the target chemical 2,2'-[(3-methylphenyl)imino]bisethanol only by a position of the methyl group in the phenyl ring, it is logical to assume that the major peak with the area of 52% corresponds to 2,2'-[(4-methylphenyl)imino]bisethanol. As the position of the methyl group is not expected to have any influence on the absorption/desorption coefficient, the result of log Koc of 2.22 derived for 2,2'-[(4-methylphenyl)imino]bisethanol can be read across to 2,2'-[(3-methylphenyl)imino]bisethanol.

Description of key information

In a GLP-compliant guideline study performed with a structural analogue of 2,2'-[(3-methylphenyl)imino]bisethanol, Accelerator, 4 major peaks were identified on the HPLC chromatogram with peak areas of 52%, 38%, 4.9% and 2.4%. As Accelerator contains ca. 50-60% of 2,2'-[(4-methylphenyl)imino]bisethanol, it is feasible to assume that the largest peak on the chromatogram corresponded to 2,2'-[(4-methylphenyl)imino]bisethanol. As 2,2'-[(4-methylphenyl)imino]bisethanol differs from the target chemical 2,2'-[(3-methylphenyl)imino]bisethanol only by the position of the methyl group in the phenyl ring, it is considered possible to read across the log Koc value of 2.22 derived for 2,2'-[(4-methylphenyl)imino]bisethanol to 2,2'-[(3-methylphenyl)imino]bisethanol.

Key value for chemical safety assessment

Koc at 20 °C:
166

Additional information

A study was performed with a structural analogue of 2,2'-[(3-methylphenyl)imino]bisethanol, Accelerator (Reaction mass of 2,2'-[(4-methylphenyl)imino]bisethanol and 2-[[2-(2-hydroxyethoxy)ethyl](4-methylphenyl)amino]-ethanol). The HPLC method (in accordance with EC C.19 and OECD 121 and in compliance with GLP) was performed to determine the adsorption coefficient (soil) of the test substance. The HPLC chromatogram of the test solution showed four major peaks (with peak areas of 52%, 38%, 4.9% and 2.4%). The log Koc values for the major peaks were 2.22, 2.44, 2.51 and 2.67, respectively. Considering that Accelerator contains > 50% of the structural analogue 2,2'-[(4-methylphenyl)imino]bisethanol which differs from the target chemical 2,2'-[(3-methylphenyl)imino]bisethanol only by a position of the methyl group in the phenyl ring, it is logical to assume that the major peak with the area of 52% corresponds to 2,2'-[(4-methylphenyl)imino]bisethanol. As the position of the methyl group is not expected to have any influence on the adsorption/desorption coefficient, the result of log Koc of 2.22 derived for 2,2'-[(4-methylphenyl)imino]bisethanol can be read across to 2,2'-[(3-methylphenyl)imino]bisethanol.