N-[3-(dimethylamino)propyl]stearamide

Endpoint summary

Additional information

Stearic acid 3-(dimethylaminopropyl)amide is a white waxy  solid at 20°C and 1013 hPa (visual assessment during test on physicochemical properties (melting point, boiling point)).

The melting point of Stearic acid 3-(dimethylaminopropyl)amide determined by differential scanning calorimetry (OECD guideline 102, adopted 27th July 1995 and EU method A.1, 30 May 2008) is reported to be 67.4°C ± 0.3°C.

The boiling point of Stearic acid 3-(dimethylaminopropyl)amide determined by differential scanning calorimetry (OECD guideline 103, adopted 27th July 1995 and EU method A.2, 30 May 2008) is reported to be 412.3 °C ± 0.3°C.

The density of Stearic acid 3-(dimethylaminopropyl)amide determinedby gas displacement pycnometry (OECD guideline 109, adopted July 27, 1995 and EU method A.3, 30 May 2008) is reported to be 0.972 g/cm³ at 20°C.

In accordance with column 2 of REACH Annex VII 7.14, a study on granulometry does not need to be conducted if the substance is marketed or used in a non solid or granular form: The substance is marketed as waxy flakes or pellets.

The vapour pressure of Stearic acid 3-(dimethylaminopropyl)amide determined by the vapour pressure balance (effusion method) according to OECD guideline 104 (adopted 27 July 1995) and EU test method A.4 (30 May 2008) is reported to be 3.4E-08 Pa at 20°C.

According to EU method A.8, 31 May 2008 the n-octanol/water partition coefficient (log Kow) of Stearic acid 3-(dimethylaminopropyl)amide was estimated by calculation based on the solubility of the test substance in n-Octanol and water.

The test substance is present to a larger extent as protonated amine as well as to a minor extent as neutral form (free amine) at environmentally relevant pH in the range of pH 4-9. As this can have a marked effect on the partition coefficient, the log Kow was estimated from the individual solubilities at pH 4, 7 and 9 to cover the relevant range. Weighted log Kow were calculated taking into account the presence of the free and protonated amine at different pH values. The weighted log Kow at pH 4, 7 and 9 are 2.00, 2.01 and 2.57, respectively.

The water solubility of Stearic acid 3-(dimethylaminopropyl)amide was determined according to OECD guideline 105, 27 July 1995, using the flask method. The water solubility of Stearic acid 3-(dimethylaminopropyl)amide is 10 mg/L at 20°C (pH 6.8).

However, based on the pKa the following distributions of free and protonated amine are present at different pH:

	free amine [%]	protonated amine [%]
pH 9	26.2	73.8
pH 7	0.4	99.6
pH 4	0	100

 

Surfactants show a complex solubility behaviour due to aggregation. The single molecule concentration reaches a limiting value at the critical micelle concentration and remains approximately constant when the total concentration further increases.

The critical micelle concentration (cmc) of Stearic acid 3-(dimethylaminopropyl)amide hydrochloride was determined according to ISO 4311, using the plate method. The cmc of Stearic acid 3-(dimethylaminopropyl)amide hydrochloride is 220 mg/L at 25°C.

The solubility of Stearic acid 3-(dimethylaminopropyl)amide in n-Octanol was determined according to OECD guideline 105, 27 July 1995, adapted for n-Octanol (flask method). The solubility of Stearic acid 3-(dimethylaminopropyl)amide in n-Octanol is 151 g/L.

A supporting study is available, in which the solubility of Stearic acid 3-(dimethylaminopropyl)amide in n-Octanol was determinedby HPLC/CAD.

The average solubility of Stearic acid 3-(dimethylaminopropyl)amide in n-Octanol was 21.6 ± 0.98%. The density of the saturated mixture was determined to be 0.832 ± 0.003 g/mL. Using the density, the solubility of Stearic acid 3-(dimethylaminopropyl)amide in n-Octanol can be converted into 180 ± 8 g/L.

The solubility of Stearic acid 3-(dimethylaminopropyl)amide hydrochloride in n-Octanol was determined according to OECD guideline 105, 27 July 1995, adapted for n-Octanol (flask method). The solubility of Stearic acid 3-(dimethylaminopropyl)amide hydrochloride in n-Octanol is 22 g/L.

 

The surface tension of Stearic acid 3-(dimethylaminopropyl)amide hydrochloride was determined according to ISO 4311, using the plate method. The surface tension vs. concentration plot showed a minimum of 37.86 mN/m at 0.22 g/L.

The flash point of Stearic acid 3-(dimethylaminopropyl)amide was analysed by the Pensky-Martens closed cup method (EU method A.9, 30 May 2008). No flash point was observed up to 260°C. According to REACH regulation Annex VII, 7.12, column II, a test on auto flammability does not need to be conducted for solids with a melting point below 160°C. The melting point of the test substance is 67.4°C.

The flammability of Stearic acid 3-(dimethylaminopropyl)amide was analysed according to the EU test method A.10 (30 May 2008). In the preliminary test no ignition of the substance was observed. According to the guideline the execution of the main test was not necessary. The test substance is not highly flammable.

Explosive properties testing does not need to be conducted as there are no chemical groups associated with explosive properties in the molecule.

Oxidising properties testing does not need to be conducted on the basis of chemical structure. According to REACH Annex IX, 7.15, column 1, a study on stability in organic solvents is only required if stability of the substance is considered to be critical.

The dissociation constant (pKa) of Stearic acid 3-(dimethylaminopropyl)amide was determined using ACD labs. The pKa is 9.45±0.28 at 25°C.

According to REACH Annex XI, 1 a study on viscosity is technically not feasible, as the substance is a solid at ambient temperature.