Octadecanoic acid, reaction products with 2-amino-2-methyl-1-propanol

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

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

Adequacy of study:

supporting study

Study period:

From February 26, 2013 to March 12, 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

KL2 due to RA

Justification for type of information:

Refer to section 13 of IUCLID for details on the read-across justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

soil/sewage sludge

Test temperature:

30°C

Details on study design: HPLC method:

Measured HPLC retention data were obtained for 11 reference substance (acetanilide, atrazine, monuron, 2,5-dichloroaniline, linuron, naphthalene, benzoic acid phenylester, 1,2,3 trichlorobenzene, fenthion, phenanthrene and 4,4' DDT). Based on these data, a calibration graph of Log k' versus log Koc was established to correlate the measured HPLC retention data of the test item with its adsorption coefficients (Koc) for soil and sewage sludge.

The capacity factors k' were calculated according to the following equation:
k' = (tR-t0)/t0
where:
tR: HPLC retention time in minutes of test and reference substances
t0: HPLC dead time in minutes (determined with formamide)

The test substance was prepared at a concentration of 500 mg/L in three replicates.The reference substances have been injected before and after the test substance to confirm that retention times had not drifted.

Analytical monitoring:

yes

Key result

Sample No.:

#1

Type:

log Koc

Value:

> 2.93 - < 4.68 dimensionless

Temp.:

30 °C

Validity criteria fulfilled:

yes

Conclusions:

Based on the results of the read across study, a similar Koc range can be considered for the test substance, C16 -18 AMP.

Executive summary:

A study was conducted to determine the adsorption coefficient (log Koc) on soil and on sewage sludge of the read across substance, Oleamide MIPA (purity: 100%), using HPLC, according to OECD Guideline 121, in compliance with GLP. In the study, measured HPLC retention data were obtained for 11 reference substances (i.e., acetanilide, atrazine, monuron, 2,5 dichloroaniline, linuron, naphathalene, benzoic acid phenylester, 1,2,3 trichlorobenzene, fenthion, phenanthrene and 4,4’ DDT). Based on these data, a calibration graph was established to correlate the measured HPLC retention data of the test substance with its adsorption coefficient for soil and sewage sludge. Under study conditions, the log Koc of the read across substance for soil and sewage sludge was determined to range from 2.93 to 4.68 at 30°C (Legay, 2013). Based on the results of the read across study, a similar Koc range can be considered for the test substance, C16 -18 AMP.

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

key study

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

Justification for type of information:

QSAR prediction from a well-known and acknowledged tool. See below under 'Overall remarks, attachments' for applicability domain.

Qualifier:

according to guideline

Guideline:

other: REACH guidance on QSARs: Chapter R.6. QSARs and grouping of chemicals

Principles of method if other than guideline:

Since the test substance is a UVCB with similar constituents varying mainly in carbon chain lengths, the Koc values were estimated for the individual components using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program followed by the determination of an overall weighted-average value using the mole fractions of all the individual components.

Computational methods:

Since the test substance is an UVCB with several constituents varying mainly in carbon chain lengths, the Koc values were estimated for the individual components using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program followed by an determination of an overall weighted-average value using the mole fractions of all the individual components.

MCI based methodology:
PCKOCWIN (version 1) estimated Koc solely with a QSAR utilizing First Order Molecular Connectivity Index (MCI). This QSAR estimation methodology is described completely in a journal article (Meylan et al, 1992) and in a report prepared for the EPA (SRC, 1991). PCKOCWIN (version 2) utilizes the same methodology, but the QSAR has been re-regressed using a larger database of experimental Koc values that includes many new chemicals and structure types.
Reference: Meylan, W., P.H. Howard and R.S. Boethling, "Molecular Topology/Fragment Contribution Method for Predicting Soil Sorption Coefficients", Environ. Sci. Technol. 26: 1560-7 (1992).

Validity of model
1. Defined endpoint: log Koc – soil adsorption coefficient of organic compounds.
2. Unambiguous algorithm:
log Koc = 0.5213 MCI + 0.60 + ΣPfN
MCI – molecular connectivity index, ΣPfN - summation of the products of all applicable correction factor coefficients available in the data set multiplied by the number of times (N) that factor is counted for the structure.
3. Applicability domain: Currently, there is no universally accepted definition of model domain. The training set of the model contains diverse molecules, so that the fragment library is abundant. It is however possible that a compound has functional groups or other structural features that are not represented in the training set and for which no fragment coefficients were developed. Additionally, there can be more instances of a given fragment than the maximum for all training set compounds. These points should be taken into consideration while interpreting test results.
Molecular weight limits of the training set: 32-665 g/mol
Log Kow limits: -2.11-9.10
4. Appropriate measures of goodness of fit, robustness and predictivity: for the statistics, training data set has been split up into two subsets: the one containing non-polar substances with no fragments subjected to corrections (i.e. those with ΣPfN = 0) and the one containing the remaining ones. For the non-polar set: N = 69 compounds, correlation coefficient R2= 0.967, standard deviation sd = 0.247 and average deviation ad = 0.199. For the second set: N = 447 compounds, correlation coefficient R2= 0.9, standard deviation sd = 0.34 and average deviation ad = 0.273. For the external validation data set: N = 158 compounds, correlation coefficient R2= 0.85, standard deviation sd = 0.583 and average deviation ad = 0.459. For the 516 compounds in the training set, 93% are within 0.6 log units and 100% within 1 log unit. For the accuracry graphs, please refer to the PDF under 'attached background material'.
5. Mechanistic interpretation if possible: The methodology and relationship between the first order molecular connectivity index (MCI) and adsorption coefficient is outlined in the reference paper: Meylan, W., P.H. Howard and R.S. Boethling, "Molecular Topology/Fragment Contribution Method for Predicting Soil Sorption Coefficients", Environ. Sci. Technol. 26: 1560-7 (1992). MCI was initially successfully used to predict soil sorption coefficients for non-polar organics, and the developed new estimation method based on MCI and series of statistically derived fragment contribution factors made it useful also for the polar ones.

Key result

Type:

Koc

Value:

ca. 15 782.64 L/kg

Remarks on result:

other: weighted average estimation using MCI method of KOCWIN v.2.00

Remarks:

log Koc: 4.2

Details on results:

Chemical names	SMILES	Mole fraction Xi = (mi/Mi)/∑ (mi/Mi)	log Koc	log Koc * xi	Domain evaulation
N-(1-Hydroxy-2-Methylpropan-2-yl) Hexadecanamide	CCCCCCCCCCCCCCCC(=O)NC(C)(C)CO	0.494140	3.7836	1.869627417	ID (Molecular weight and fragments)
N-(1-Hydroxy-2-Methylpropan-2-yl) Octadecanamide	CCCCCCCCCCCCCCCCCC(=O)NC(C)(C)CO	0.455163	4.393	1.999530126	ID (Molecular weight and fragments)
Methyl Stearate	CCCCCCCCCCCCCCCCCC(=O)OC	0.024099	4.676	0.112686999	ID (Molecular weight and fragments)
Methyl palmitate	CCCCCCCCCCCCCCCC(=O)OC	0.026598	4.155	0.11051626	ID (Molecular weight and fragments)
				4.092360802

ID = in domain; OD = out of doamin

SMILES : CCCCCCCCCCCCCCCC(=O)NC(C)(C)CO
CHEM  :
MOL FOR: C20 H41 N1 O2	Domain evaluation	MW (Training set)
MOL WT : 327.56	ID	665.02
--------------------------- KOCWIN v2.00 Results ---------------------------
Koc Estimate from MCI:
---------------------
First Order Molecular Connectivity Index ........... : 11.015
Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 6.3420
Fragment Correction(s):		Training set
1  N-CO-C (aliphatic carbon) ............ : -1.0277	ID	1
1  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.2127	ID	5
1  Aliphatic Alcohol (-C-OH) ........... : -1.3179	ID	1
Corrected Log Koc .................................. : 3.7836
Estimated Koc: 6076 L/kg  <===========
Koc Estimate from Log Kow:
-------------------------
Log Kow (Kowwin estimate) ......................... : 6.08
Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 4.2881
Fragment Correction(s):
1  N-CO-C (aliphatic carbon) ............ : -0.0038
1  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0218
1  Aliphatic Alcohol (-C-OH) ........... : -0.4114
Corrected Log Koc .................................. : 3.8511
Estimated Koc: 7098 L/kg  <===========
SMILES : CCCCCCCCCCCCCCCCCC(=O)NC(C)(C)CO
CHEM  :
MOL FOR: C22 H45 N1 O2	Domain evaluation	MW (Training set)
MOL WT : 355.61	ID	665.02
--------------------------- KOCWIN v2.00 Results ---------------------------
Koc Estimate from MCI:
---------------------
First Order Molecular Connectivity Index ........... : 12.015
Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 6.8633
Fragment Correction(s):		Training set
1  N-CO-C (aliphatic carbon) ............ : -1.0277	ID	1
1  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.2127	ID	5
1  Aliphatic Alcohol (-C-OH) ........... : -1.3179	ID	1
Corrected Log Koc .................................. : 4.3049
Estimated Koc: 2.018e+004 L/kg  <===========
Koc Estimate from Log Kow:
-------------------------
Log Kow (Kowwin estimate) ......................... : 7.06
Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 4.8302
Fragment Correction(s):
1  N-CO-C (aliphatic carbon) ............ : -0.0038
1  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0218
1  Aliphatic Alcohol (-C-OH) ........... : -0.4114
Corrected Log Koc .................................. : 4.3932
Estimated Koc: 2.473e+004 L/kg  <===========
SMILES : CCCCCCCCCCCCCCCCCC(=O)OC
CHEM  :
MOL FOR: C19 H38 O2	Domain evaluation	MW (Training set)
MOL WT : 298.51	ID	665.02
--------------------------- KOCWIN v2.00 Results ---------------------------
Koc Estimate from MCI:
---------------------
First Order Molecular Connectivity Index ........... : 10.308
Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 5.9734
Fragment Correction(s):		Training set
1  Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -1.2970	ID	1
Corrected Log Koc .................................. : 4.6764
Estimated Koc: 4.747e+004 L/kg  <===========
Koc Estimate from Log Kow:
-------------------------
Log Kow (experimental DB) ......................... : 8.35
Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 5.5437
Fragment Correction(s):
1  Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -0.0656
Corrected Log Koc .................................. : 5.4781
Estimated Koc: 3.007e+005 L/kg  <===========
SMILES : CCCCCCCCCCCCCCCC(=O)OC
CHEM  :
MOL FOR: C17 H34 O2	Domain evaluation	MW (Training set)
MOL WT : 270.46	ID	665.02
--------------------------- KOCWIN v2.00 Results ---------------------------
Koc Estimate from MCI:
---------------------
First Order Molecular Connectivity Index ........... : 9.308
Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 5.4521
Fragment Correction(s):		Training set
1  Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -1.2970	ID	1
Corrected Log Koc .................................. : 4.1551
Estimated Koc: 1.429e+004 L/kg  <===========
Koc Estimate from Log Kow:
-------------------------
Log Kow (experimental DB) ......................... : 7.38
Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 5.0072
Fragment Correction(s):
1  Ester (-C-CO-O-C-) or (HCO-O-C) ...... : -0.0656
Corrected Log Koc .................................. : 4.9416
Estimated Koc: 8.742e+004 L/kg  <===========

Validity criteria fulfilled:

not applicable

Conclusions:

Using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program (EPI Suite v4.11), the estimated Koc of the individual constituents ranged from 6076 to 47470 L/kg (i.e., equivalent to log Koc ranging from 3.78 to 4.68), leading to a weighted average log Koc value of the test substance at 15782.64 L/kg (or log Koc: 4.2)

Executive summary:

The soil adsorption coefficient (Koc) of the test substance, C16-18 AMP, was estimated using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program (EPI Suite v4.11). Since the test substance is a UVCB with similar constituents varying mainly in carbon chain length, Koc values were estimated for the individual constituents followed by the determination of an overall weighted-average value based on mole fractions. SMILES codes were used as the input parameter. The estimated Koc of the individual constituents ranged from 6076 to 47470 L/kg (i.e., equivalent to log Koc ranging from 3.78 to 4.68), leading to a weighted average Koc for the test substance of 15782.64 L/kg (log Koc: 4.2) (US EPA, 2018). This range of Koc indicates strong sorption potential to soil/sediment and negligible to slow migration to ground water (US EPA, 2012). The estimates for all the constituents can be considered to be reliable and accurate as they are all within the applicability domain.

Description of key information

The weighted average Koc and log Koc of the test substance, C16-18 AMP, was estimated to be 15782.64 L/kg or 4.2 respectively using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program (EPISuite v4.11). This is further supported by the experimental Koc values of the read across substance, which ranged between >2.93 -<4.68 at 30°C.

Key value for chemical safety assessment

Koc at 20 °C:

15 782.64

Additional information

Study 1:

The soil adsorption coefficient (Koc) of the test substance, C16-18 AMP, was estimated using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program (EPI Suite v4.11). Since the test substance is a UVCB with similar constituents varying mainly in carbon chain length, Koc values were estimated for the individual constituents followed by the determination of an overall weighted-average value based on mole fractions. SMILES codes were used as the input parameter. The estimated Koc of the individual constituents ranged from 6076 to 47470 L/kg (i.e., equivalent to log Koc ranging from 3.78 to 4.68), leading to a weighted average Koc for the test substance of 15782.64 L/kg (log Koc: 4.2) (US EPA, 2018). This range of Koc indicates strong sorption potential to soil/sediment and negligible to slow migration to ground water (US EPA, 2012). The estimates for all the constituents can be considered to be reliable and accurate as they are all within the applicability domain.

Study 2:

A study was conducted to determine the adsorption coefficient (log Koc) on soil and on sewage sludge of the read across substance, Oleamide MIPA (purity: 100%), using HPLC, according to OECD Guideline 121, in compliance with GLP. In the study, measured HPLC retention data were obtained for 11 reference substances (i.e., acetanilide, atrazine, monuron, 2,5 dichloroaniline, linuron, naphathalene, benzoic acid phenylester, 1,2,3 trichlorobenzene, fenthion, phenanthrene and 4,4’ DDT). Based on these data, a calibration graph was established to correlate the measured HPLC retention data of the test substance with its adsorption coefficient for soil and sewage sludge. Under study conditions, the log Koc of the read across substance for soil and sewage sludge was determined to range from 2.93 to 4.68 at 30°C (Legay, 2013). Based on the results of the read across study, a similar Koc range can be considered for the test substance, C16 -18 AMP.

Given that the results of the QSAR model as well as the read across study are in the same range, the estimated weighted average Koc value of the test substance, C16-18 AMP, has been considered further for the hazard or risk assessment.​

Given that the results of the QSAR model as well as the read across study are more or less in the same range, the estimated weighted avergae Koc value of the test substance, C16-18 AMP, has been considered further for the hazard or risk assessment.

[LogKoc: 4.2]