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Melting point / freezing point

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Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 16 May 2012 to 25 January 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.1 (Melting / Freezing Temperature)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
2012-12-15
Type of method:
differential scanning calorimetry
Key result
Melting / freezing pt.:
>= 60.9 - <= 61.9 °C
Atm. press.:
1 013 hPa

Six assays were performed during the test, the temperature values obtained for the melting point varied between 52.6 and 67.7 °C.

The mean value for the melting point a is explained as the mean of at least two assays for which the melting point value or the boiling point value are in the range of the estimated accuracy of the method: ± 0.5 °C up to 326.9 °C and ± 2.0 °C

above 326.9 °C.

Two assays were contained between the range for the melting point.

Assays No. Melting point (°C)
1 /
2 67.7
3 52.6
4 62.3
5 61.5
6 61.2

/ corresponds to the non integration of the curve.

The results written in bold were taken into account.

Conclusions:
The mean melting point of the test item was 61.4 ± 0.5 °C.
Executive summary:

The melting point of the test item (= substance EC 939-455-3) was investigated in a GLP-compliant study performed in accordance with OECD Guideline 102 (Melting point / Melting Range) and EU Method A.1 (Melting / Freezing Temperature). The mean melting point of the test item was 61.4 ± 0.5 °C.

Endpoint:
melting point/freezing point
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
C8-C18 AAPHS and C12-18 AAPHS have the same functional groups, and general composition. The main variable resides in the alkyl chain distribution.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source chemical = C8-18 cocamidopropyl hydroxysultaine (EC 939-455-3).
Target chemical = C12-18 cocamidopropyl hydroxysultaine (EC 939-457-4).

3. ANALOGUE APPROACH JUSTIFICATION
The alkyl C-chain distribution of the source chemical significantly overlaps with the one of the target chemical, the C12-alkyl derivative being the major constituent in both chemicals. The structural differences in side C-chains is not expected to lead to significant differences on phys-chem properties.

4. DATA MATRIX
See "Documentation and scientific justification of the read-across approach" in section 13.2.
Reason / purpose:
read-across source
Key result
Melting / freezing pt.:
>= 60.9 - <= 61.9 °C
Atm. press.:
1 013 hPa
Remarks on result:
other: read-across from EC 939-455-3
Conclusions:
By analogy with the source substance EC 939-455-3, a melting point of 61.4 ± 0.5°C was reported for the target substance 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-(C12-18(even numbered) acyl) derivs., hydroxides, inner salts (EC 939-457-4).

Description of key information

As the melting point of the substance EC 939-457-4 has not been determined experimentally, a read-across approach was followed to fill in the endpoint. The melting point of a structural analogue substance (= source substance EC 939-455-3) was investigated in a GLP-compliant study (Ricau, 2013) performed in accordance with OECD Guideline 102 (Melting point / Melting Range) and EU Method A.1 (Melting / Freezing Temperature). The mean melting point of the analogue substance was 61.4 ± 0.5 °C. By analogy, a melting point of 61.4 ± 0.5°C was reported for the target substance 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-(C12-18(even numbered) acyl) derivs., hydroxides, inner salts (EC 939-457-4).

The alkyl C-chain distribution of the source substance EC 939-455-3 significantly overlaps with the one of the target substance EC 939-457-7, the C12-alkyl derivative being the major constituent in both chemicals. The structural differences in side C-chains is not expected to lead to significant differences on phys-chem properties.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
61.4 °C

Additional information

The melting point of the structural analogue substance (= source substance EC 939-455-3) was investigated in a GLP-compliant study (Ricau, 2013) performed in accordance with standard methods, without deviations. The study is considered as reliable (Klimisch 1) and was selected as key study for the endpoint of the target substance EC 939-457-4.