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

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

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. Refer to 'Overall remarks' for applicability domain and attached background material for chemical fragments and values used by the HYDRO program to calculate hydrolysis rate constants.

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, the hydrolysis half life values were estimated for the individual components using SMILES codes as the input parameter.

GLP compliance:

no

Transformation products:

not specified

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Remarks on result:

other: Predicted data

Remarks:

Not hydrolysable

QSAR Prediction results

Chemical names	SMILES	Hydrolysis (Half life)
N-(1-Hydroxy-2-Methylpropan-2-yl) Hexadecanamide	CCCCCCCCCCCCCCCC(=O)NC(C)(C)CO	>1 year (assumed based on structure and experimental half-lives of known amides)
N-(1-Hydroxy-2-Methylpropan-2-yl) Octadecanamide	CCCCCCCCCCCCCCCCCC(=O)NC(C)(C)CO	>1 year (assumed based on structure and experimental half-lives of known amides)
Methyl Stearate	CCCCCCCCCCCCCCCCCC(=O)OC	266 days (at pH 8)
Methyl palmitate	CCCCCCCCCCCCCCCC(=O)OC	266 days (at pH 8)

Hydrolysis

SMILES : CCCCCCCCCCCCCCCC(=O)NC(C)(C)CO

CHEM  :

MOL FOR: C20 H41 N1 O2

MOL WT : 327.56

--------------------------- HYDROWIN v2.00 Results ---------------------------

Hydrolyzable Function detected: Amides

-C-C(=O)-N-C-

With the exception of a few halogenated acetamides, most amides

hydrolyze to acids extremely slowly at 25 degC and pH7 with half-lives

measured in centuries. Electronegative groups on carbon or nitrogen

greatly accelerate base catalyzed hydrolysis, but alkyl groups on

nitrogen retard both acid and base catalyzed processes. No neutral

hydrolysis is evident (Mabey and Mill, 1978). Selected amides

half-lives include:

Half-Live (in years at 25C, pH7)

Acetamide               3950

Chloroacetamide         1.46

Dichloroacetamide       0.73

Trichloroacetamide      0.23

N-Methylacetamide       38000

Additional experimental amide data are available in the HYDRO on-line

User Guide (help file).

SMILES : CCCCCCCCCCCCCCCCCC(=O)NC(C)(C)CO

CHEM  :

MOL FOR: C22 H45 N1 O2

MOL WT : 355.61

--------------------------- HYDROWIN v2.00 Results ---------------------------

Hydrolyzable Function detected: Amides

-C-C(=O)-N-C-

With the exception of a few halogenated acetamides, most amides

hydrolyze to acids extremely slowly at 25 degC and pH7 with half-lives

measured in centuries. Electronegative groups on carbon or nitrogen

greatly accelerate base catalyzed hydrolysis, but alkyl groups on

nitrogen retard both acid and base catalyzed processes. No neutral

hydrolysis is evident (Mabey and Mill, 1978). Selected amides

half-lives include:

Half-Live (in years at 25C, pH7)

Acetamide               3950

Chloroacetamide         1.46

Dichloroacetamide       0.73

Trichloroacetamide      0.23

N-Methylacetamide       38000

Additional experimental amide data are available in the HYDRO on-line

User Guide (help file).

SMILES : CCCCCCCCCCCCCCCCCC(=O)OC

CHEM  :

MOL FOR: C19 H38 O2

MOL WT : 298.51

--------------------------- HYDROWIN v2.00 Results ---------------------------

NOTE: Fragment(s) on this compound are NOT available from the fragment

library. Substitute(s) have been used!!! Substitute R1, R2, R3,

or R4 fragments are marked with double astericks "**".

ESTER: R1-C(=O)-O-R2               ** R1: n-Octyl-

R2: -CH3

Kb hydrolysis at atom # 18: 3.016E-002 L/mol-sec

Total Kb for pH > 8 at 25 deg C : 3.016E-002 L/mol-sec

Kb Half-Life at pH 8:    266.000 days

Kb Half-Life at pH 7:      7.283 years

SMILES : CCCCCCCCCCCCCCCC(=O)OC

CHEM  :

MOL FOR: C17 H34 O2

MOL WT : 270.46

--------------------------- HYDROWIN v2.00 Results ---------------------------

NOTE: Fragment(s) on this compound are NOT available from the fragment

library. Substitute(s) have been used!!! Substitute R1, R2, R3,

or R4 fragments are marked with double astericks "**".

ESTER: R1-C(=O)-O-R2               ** R1: n-Octyl-

R2: -CH3

Kb hydrolysis at atom # 16: 3.016E-002 L/mol-sec

Total Kb for pH > 8 at 25 deg C : 3.016E-002 L/mol-sec

Kb Half-Life at pH 8:    266.000 days

Kb Half-Life at pH 7:      7.283 years

Validity criteria fulfilled:

yes

Conclusions:

Under study conditions, the test substance is expected to be hydrolytically stable.

Executive summary:

The hydrolysis half-life of the test substance, C16-18 AMP, was estimated using the HYDROWIN v2.00 program of EPI Suite v4.11. Since the test substance is a UVCB, hydrolysis half-life values were estimated for the individual components using SMILES codes as the input parameter. The major constituents were detected to be ‘amides’ which are known to hydrolyse extremely slowly at 25°C and pH,7 with half-lives measured in centuries. Further presence of electronegative groups on carbon or nitrogen is also known to greatly accelerate base-catalysed hydrolysis, but alkyl groups on nitrogen retard both acid and base-catalysed processes. No neutral hydrolysis was evident (Mabey and Mill, 1978). Therefore, considering that the test substance is an ‘amide’ with long alkyl groups (ranging from C16-18 carbon chains) bonded to the carbonyl atom and alkyl group to the nitrogen atom, both of which are electron-donating groups known to retard the acidic or basic hydrolysis process, the hydrolysis half-life values for the test substance can be assumed to be in centuries or >1 year. This is supported by higher experimental half-life values available for two short chain amides: N-methylacetamide and acetamide (US EPA, 2018). Hence, the test substance is expected to be hydrolytically stable (US EPA, 2012)

Description of key information

Based on the results of the HYDROWIN v2.00 program for the individual constituents, the test substance can be overall considered to be hydrolytically stable.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

The hydrolysis half-life of the test substance, C16-18 AMP, was estimated using the HYDROWIN v2.00 program of EPI Suite v4.11. Since the test substance is a UVCB, hydrolysis half-life values were estimated for the individual components using SMILES codes as the input parameter. The major constituents were detected to be ‘amides’ which are known to hydrolyse extremely slowly at 25°C and pH,7 with half-lives measured in centuries. Further presence of electronegative groups on carbon or nitrogen is also known to greatly accelerate base-catalysed hydrolysis, but alkyl groups on nitrogen retard both acid and base-catalysed processes. No neutral hydrolysis was evident (Mabey and Mill, 1978). Therefore, considering that the test substance is an ‘amide’ with long alkyl groups (ranging from C16-18 carbon chains) bonded to the carbonyl atom and alkyl group to the nitrogen atom, both of which are electron-donating groups known to retard the acidic or basic hydrolysis process, the hydrolysis half-life values for the test substance can be assumed to be in centuries or >1 year. This is supported by higher experimental half-life values available for two short chain amides: N-methylacetamide and acetamide (US EPA, 2018). Hence, the test substance is expected to be hydrolytically stable (US EPA, 2012).