Nα-acetyl-DL-tryptophan

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:

09 Jul - 28 Aug 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

adopted in 1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

adopted in 2008

Deviations:

no

GLP compliance:

no

Type of method:

differential scanning calorimetry

Specific details on test material used for the study:

Storage conditions: ambient temperature (10 – 30 °C)

Melting / freezing pt.:

ca. 208.6 °C

Atm. press.:

ca. 1 013 hPa

Decomposition:

yes

Decomp. temp.:

>= 208.6 °C

Remarks on result:

other: Three DSC measurments in aluminum crucibles with a hole showed an endothermal effect in the temperature of 208.6°C (median value). At higher temperatures further endothermal effects were observed which were the melting of the test item.

Results
DSC
Two DSC measurements with a heating rate of 10 K/min showed an endothermal effect (melting) in the temperature range of 195 – 220 °C with an onset temperature of 208.6 °C (median value). At higher temperatures further endothermal effects were seen, which were beyond the melting of the test item.

Table 1 – Melting point DSC measurement results

Test item [mg]	Final temperature [°C]	Temperature range (melting) [°C]	Onset [°C]	Observations
7.76	500	200 – 220	208.45	Measurement continued above the melting
7.78	500	195 – 220	208.60
4.88	250	200 – 220	208.63	---

 

Capillary Method
Table 2 – Results of Capillary Method

Set point [°C]	End point [°C]	Remarks
150	350	Approx. 208 °C: test item started to melt under formation of bubbles Approx. 214 °C: test item was melted Approx. 240 °C: test item discoloured to yellow, test item left the observation field

 

Conclusion: The test item melted under decomposition at 208.6 °C.

Description of key information

The test item melted under decomposition at 208.6 °C (OECD 102, DSC).

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

208.6 °C