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Reference
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 an well known and acknowledged tool. See below under 'Overall remarks, attachments' for applicability domain.
Qualifier:
according to
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. 256.24 L/kg
Remarks on result:
other: weighted average estimation using MCI method of KOCWIN v.2.00
Remarks:
i.e., equivalent to log Koc: 2.4

Details on results:

Chemical names SMILES Mole fraction Xi = (mi/Mi)/∑ (mi/Mi) Koc Koc * xi log Koc log Koc * xi Domain evaluation
C6 Amide CCCCCC(=O)N(CCO)CCO 0.077643158 10 7.76E-01 1.00 0.077643 ID (Molecular weight ) and OD (molecular fragments)
C8 Amide CCCCCCCC(=O)N(CCO)CCO 0.062045709 10 6.20E-01 1.00 0.062046 ID (Molecular weight ) and OD (molecular fragments)
C10 Amide CCCCCCCCCC(=O)N(CCO)CCO 0.434091466 11.9 5.17E+00 1.08 0.466886 ID (Molecular weight ) and OD (molecular fragments)
C12 Amide CCCCCCCCCCCC(=O)N(CCO)CCO 0.191481661 39.53 7.57E+00 1.60 0.305782 ID (Molecular weight ) and OD (molecular fragments)
C14 Amide CCCCCCCCCCCCCC(=O)N(CCO)CCO 0.01830673 131.3 2.40E+00 2.12 0.038778 ID (Molecular weight ) and OD (molecular fragments)
C16 Amide CCCCCCCCCCCCCCCC(=O)N(CCO)CCO 0.072824392 436.1 3.18E+01 2.64 0.192226 ID (Molecular weight ) and OD (molecular fragments)
C18 Amide CCCCCCCCCCCCCCCCCC(=O)N(CCO)CCO 0.016696718 1448 2.42E+01 3.16 0.052774 ID (Molecular weight ) and OD (molecular fragments)
C18:1 Amide CCCCCCCCC=CCCCCCCCC(=O)N(CCO)CCO 0.035432682 1448 5.13E+01 3.16 0.111995 ID (Molecular weight ) and OD (molecular fragments)
C18:2 Amide CCCCCC=CCC=CCCCCCCCC(=O)N(CCO)CCO 0.091477484 1448 1.32E+02 3.16 0.289139 ID (Molecular weight ) and OD (molecular fragments)
        2.56E+02   1.60
log Koc =  2.41

ID = in domain; OD = out of doamin

Koc
SMILES : CCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C10 H21 N1 O3  ID 665.02
MOL WT : 203.28    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 6.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 4.1221    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 0.0331    
        Over Correction Adjustment to Lower Limit Log Koc ... : 1.0000    
     
                        Estimated Koc: 10 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : -0.06    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 0.8919    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 0.0217    
     
                        Estimated Koc: 1.051 L/kg  <===========    
     
     
     
SMILES : CCCCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C12 H25 N1 O3  ID 665.02
MOL WT : 231.34    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 7.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 4.6434    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 0.5544    
        Over Correction Adjustment to Lower Limit Log Koc ... : 1.0000    
     
                        Estimated Koc: 10 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : 0.92    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 1.4340    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 0.5637    
     
                        Estimated Koc: 3.662 L/kg  <===========    
     
     
     
SMILES : CCCCCCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C14 H29 N1 O3  ID 665.02
MOL WT : 259.39    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 8.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 5.1647    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 1.0757    
     
                        Estimated Koc: 11.9 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : 1.90    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 1.9760    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 1.1058    
     
                        Estimated Koc: 12.76 L/kg  <===========    
     
     
     
SMILES : CCCCCCCCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C16 H33 N1 O3  ID 665.02
MOL WT : 287.45    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 9.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 5.6860    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 1.5970    
     
                        Estimated Koc: 39.53 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : 2.89    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 2.5236    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 1.6534    
     
                        Estimated Koc: 45.02 L/kg  <===========    
     
     
     
SMILES : CCCCCCCCCCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C18 H37 N1 O3  ID 665.02
MOL WT : 315.50    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 10.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 6.2073    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 2.1183    
     
                        Estimated Koc: 131.3 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : 3.87    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 3.0657    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 2.1955    
     
                        Estimated Koc: 156.8 L/kg  <===========    
     
     
     
SMILES : CCCCCCCCCCCCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C20 H41 N1 O3  ID 665.02
MOL WT : 343.55    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 11.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 6.7286    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 2.6396    
     
                        Estimated Koc: 436.1 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : 4.85    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 3.6078    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 2.7375    
     
                        Estimated Koc: 546.4 L/kg  <===========    
     
     
     
SMILES : CCCCCCCCCCCCCCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C22 H45 N1 O3  ID 665.02
MOL WT : 371.61    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 12.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 7.2499    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 3.1609    
     
                        Estimated Koc: 1448 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : 5.83    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 4.1498    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 3.2796    
     
                        Estimated Koc: 1904 L/kg  <===========    
     
     
     
SMILES : CCCCCCCCC=CCCCCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C22 H43 N1 O3  ID 665.02
MOL WT : 369.59    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 12.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 7.2499    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 3.1609    
     
                        Estimated Koc: 1448 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : 5.62    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 4.0337    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 3.1634    
     
                        Estimated Koc: 1457 L/kg  <===========    
     
     
SMILES : CCCCCC=CCC=CCCCCCCCC(=O)N(CCO)CCO    
CHEM  :  Domain evaluation MW (Training set)
MOL FOR: C22 H41 N1 O3  ID 665.02
MOL WT : 367.58    
--------------------------- KOCWIN v2.00 Results ---------------------------    
     
 Koc Estimate from MCI:    
 ---------------------    
        First Order Molecular Connectivity Index ........... : 12.757    
        Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 7.2499    
        Fragment Correction(s):   Training set
                 1  N-CO-C (aliphatic carbon) ............ : -1.0277 ID 1
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.4255 ID 5
                 2  Aliphatic Alcohol (-C-OH) ........... : -2.6358 OD 1
        Corrected Log Koc .................................. : 3.1609    
     
                        Estimated Koc: 1448 L/kg  <===========    
     
 Koc Estimate from Log Kow:    
 -------------------------    
        Log Kow (Kowwin estimate) ......................... : 5.40    
        Non-Corrected Log Koc (0.55313 logKow + 0.9251) .... : 3.9120    
        Fragment Correction(s):    
                 1  N-CO-C (aliphatic carbon) ............ : -0.0038    
                 2  Nitrogen to Carbon (aliphatic) (-N-C).. : -0.0436    
                 2  Aliphatic Alcohol (-C-OH) ........... : -0.8229    
        Corrected Log Koc .................................. : 3.0418    
     
                        Estimated Koc: 1101 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 0.62 to 132.46 (log Koc ranged from 1 to 3.16) leading to aweighted average Koc value of 256.24 (i.e., log Koc = 2.4).
Executive summary:

The soil adsorption coefficient (Koc) value for the test substance, C10-12 and C18-unsatd. DEA, was estimated using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program of EPI Suite v4.00 - v4.11. 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 followed by the determination of an overall weighted-average value using the mole fractions of all the individual components. SMILES codes were used as the input parameter for the log Koc estimation for the individual constituents. The estimated Koc of the individual constituents ranged from 0.62 to 132.46 (log Koc ranged from 1 to 3.16) leading to aweighted average Koc value of 256.24 (i.e., log Koc = 2.4) (US EPA, 2018). This range of Koc indicates low sorption to soil / sediment, moderate migration to ground water (US EPA, 2012). The estimates for the major constituents are considered to be reliable with restrictions, as they do not completely fall within of the applicability domain.

Description of key information

Using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program (EPI Suite v4.11), the weighted average Koc value of the test substance was calculated at 256.24 L/kg (i.e., equivalent to log Koc = 2.4).

Key value for chemical safety assessment

Koc at 20 °C:
256.24

Additional information

The soil adsorption coefficient (Koc) value for the test substance, C10-12 and C18-unsatd. DEA, was estimated using the MCI (Molecular Connectivity Index) approach of the KOCWIN v2.00 program of EPI Suite v4.00 - v4.11. 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 followed by the determination of an overall weighted-average value using the mole fractions of all the individual components. SMILES codes were used as the input parameter for the log Koc estimation for the individual constituents. The estimated Koc of the individual constituents ranged from 0.62 to 132.46 (log Koc ranged from 1 to 3.16) leading to aweighted average Koc value of 256.24 (i.e., log Koc = 2.4) (US EPA, 2018). This range of Koc indicates low sorption to soil / sediment, moderate migration to ground water (US EPA, 2012). The estimates for the major constituents are considered to be reliable with restrictions, as they do not completely fall within of the applicability domain.

[LogKoc: 2.41]