Acetylcysteine

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-02-28 to 2018-08-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7200 (Melting Point / Melting Range)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Key result

Melting / freezing pt.:

110.4 °C

Atm. press.:

1 013.25 hPa

Decomposition:

no

Sublimation:

no

During the heating phase a distinct endothermic effect was observed in the temperature range of 100 – 140 °C, which can be assigned to the melting of the test item.

As the onset temperatures in both tests do not deviate by more than 0.5 K from their mean value of 110.44 °C, this temperature can be used as melting point. The test item has a melting point of 110.4 °C, which could be confirmed by the capillary method (110.2 °C).

Conclusions:

The melting point was determined to be 110.4 °C at 1013.25 hPa.

Executive summary:

A study was conducted according to OECD test guideline 102, Regulation (EC) No 440/2008 method A.1 and EPA OCSPP test guideline 830.7200 to determine the melting point of the test item using differential scanning calorimetry. The test item was weighed in under air into the aluminium crucibles. Two tests with about 19 – 22 mg of the test item were performed. As reference crucible, an empty aluminium crucible was used. Under ambient conditions, the test item is solid. Therefore the tests were started at ambient temperature. The temperature was then increased up to 500 °C at a constant heating rate of 10 K/min under air. For a verification of the DSC-measurements further measurements with the capillary method were performed. In the temperature range of 100 – 140 °C, an endothermic effect (melting) was observed. For the measurements of the melting behaviour by means of the capillary method the test item was filled into three capillaries to about 4 - 6 mm filling height. The capillaries were placed in the apparatus and heated up from 100 °C to 300 °C, with a heating rate of 1 °K/min. As the onset temperatures in both tests do not deviate by more than 0.5 K from their mean value of 110.44 °C, this temperature was determined as melting point which was confirmed by the capillary method (110.2 °C) (reference 4.2 -1).

Description of key information

Melting point was determined to be 110.4 °C at 1013.25 hPa.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

110.4 °C

Additional information

A study was conducted according to OECD test guideline 102, Regulation (EC) No 440/2008 method A.1 and EPA OCSPP test guideline 830.7200 to determine the melting point of the test item using differential scanning calorimetry. The test item was weighed in under air into the aluminium crucibles. Two tests with about 19 – 22 mg of the test item were performed. As reference crucible, an empty aluminium crucible was used. Under ambient conditions, the test item is solid. Therefore the tests were started at ambient temperature. The temperature was then increased up to 500 °C at a constant heating rate of 10 K/min under air. For a verification of the DSC-measurements further measurements with the capillary method were performed. In the temperature range of 100 – 140 °C, an endothermic effect (melting) was observed. For the measurements of the melting behaviour by means of the capillary method the test item was filled into three capillaries to about 4 - 6 mm filling height. The capillaries were placed in the apparatus and heated up from 100 °C to 300 °C, with a heating rate of 1 °K/min. As the onset temperatures in both tests do not deviate by more than 0.5 K from their mean value of 110.44 °C, this temperature was determined as melting point which was confirmed by the capillary method (110.2 °C) (reference 4.2 -1).