2,3-dihydro-1,4-dihydroxyanthraquinone

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: ASTM E 537

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

thermal analysis

Remarks:

Differential Thermal Analysis (DTA)

Specific details on test material used for the study:

Batch number: CHA2016
Physical condition: Orange powder
Expiration date: 2017-09-16
Storage: Room temperature

Key result

Melting / freezing pt.:

152.7 °C

Atm. press.:

1 013.25 hPa

Decomposition:

no

Remarks on result:

other: average temperature

Melting / freezing pt.:

152.8 °C

Atm. press.:

1 013.25 hPa

Decomposition:

no

Melting / freezing pt.:

152.9 °C

Atm. press.:

1 013.25 hPa

Decomposition:

no

Melting / freezing pt.:

152.5 °C

Atm. press.:

1 013.25 hPa

Decomposition:

no

In the DTA-plots were two endothermic peaks which could be the melting point: fist peak at about 122 °C, second peak at about 153 °C. to decide, which peak belongs to the melting point, the melting behaviour war observed in the so called Büchi-apparature. This apparature allows the visual monitoring of the sample. The Büchi-apparature was pre-heated to 110 °C and then the sample was introduced. The temperature rate was 1 k/min. In the range of 122 °C no optical changing of the sample was observed. In the range of 152 °C a clear changing of the phase and reduction of volume was observed. So it is shown, that the peak at about 152 °C is the melting peak. The exact determination of the melting temperature of the three trials by the evaluation program gives 152.8, 152.9 and 152.5 °C. The average temperature is 152.7 °C.

Conclusions:

Dihydrochinizarin shows a melting point of 152.7 °C.

Executive summary:

The test was performed as stipulated in EC Test Procedure A.1 'Melting/Freezing Temperature' – ASTM E 537 ‘Standard method for assessing the thermal stability of chemicals by methods of differential thermal analysis’. The Differential Thermal Analysis (DTA) was used. Dihydrochinizarin (trial 1: 18 mg (no.1), trial 2: 19,4 mg (no.2), trial 3: 20.9 mg (no. 3)) was heated in a glass vessel at a linear rate of 1 K/min up to 180 °C. The measurement was recorded electronically. In the DTA-plots were two endothermic peaks which could be the melting point: first peak at about 122 °C, second peak at about 153 °C. to decide, which peak belongs to the melting point, the melting behaviour was observed in the so called Büchi-apparature. The Büchi-apparature was pre-heated to 110 °C and then the sample was introduced. The temperature rate was 1 k/min. In the range of 122 °C no optical changing of the sample was observed. In the range of 152 °C a clear changing of the phase and reduction of volume was observed. So it is shown, that the peak at about 152 °C is the melting peak.

The exact determination of the melting temperature of the three trials by the evaluation program gives 152.8, 152.9 and 152.5 °C. The average temperature is 152.7 °C.

Description of key information

The test was performed as stipulated in EC Test Procedure A.1 'Melting/Freezing Temperature' – ASTM E 537 ‘Standard method for assessing the thermal stability of chemicals by methods of differential thermal analysis’. The Differential Thermal Analysis (DTA) was used. In the DTA-plots were two endothermic peaks which could be the melting point: first peak at about 122 °C, second peak at about 153 °C. to decide, which peak belongs to the melting point. In the range of 122 °C no optical changing of the sample was observed. In the range of 152 °C a clear changing of the phase and reduction of volume was observed. So it is shown, that the peak at about 152 °C is the melting peak.

The exact determination of the melting temperature of the three trials by the evaluation program gives 152.8, 152.9 and 152.5 °C. The average temperature is 152.7 °C.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

152.7 °C

Additional information

Dihydrochinizarin (trial 1: 18 mg (no.1), trial 2: 19,4 mg (no.2), trial 3: 20.9 mg (no. 3)) was heated in a glass vessel at a linear rate of 1 K/min up to 180 °C. The measurement was recorded electronically.

The melting behaviour was observed in the so called Büchi-apparature. The Büchi-apparature was pre-heated to 110 °C and then the sample was introduced. The temperature rate was 1 k/min.