Hydroxylammonium chloride

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:

10 Mar - 03 May 2016

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)

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

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), dry

Melting / freezing pt.:

ca. 154.1 °C

Atm. press.:

ca. 1 013 hPa

Decomposition:

yes

Decomp. temp.:

> 154.1 °C

Results
DSC measurement
Three measurements with a heating rate of 10 K/min showed an endothermal effect (melting) in the range of 140 to 170 °C. This was directly followed by an exothermal effect. The DSC measurements with a final temperature of 500 °C showed further endothermal and exothermal effects up to the final temperature. The onset temperature was derived from the intersection of the tangent line with the highest slope of the endothermal peak with the baseline.

An additional DSC measurement was done to determine whether melting was accompanied by decomposition. Therefore, the measurement was stopped at 162 °C. It showed an endothermal effect starting at 145 °C, no mass loss occurred.

Table 1 – Melting point – DSC measurement

Test item [mg]	Starting temperature [°C]	Final test temperature [°C]	Temperature range (melting) [°C]	Onset [°C]	Observations
6.91	25	500	140 – 165	154.26	Measurement was continued after melting
24.41			140 – 170	154.16
8.41		200	145 – 165	153.85	Test item was a solidified melt after the measurement, mass loss: 56%
16.97		162	Start: 145	-	Test item was a solidified melt after the measurement, no mass loss

 

Capillary tube in a metal block
To clarify the DSC results, a measurement with the capillary method was done.

Table 2 – Capillary method results

Set point [°C]	End point [°C]	Remarks
100	200	100 °C: test item appeared unchanged Approx. 125 °C: test item started to melt Approx. 163 °C: test item was completely molten Approx. 165 °C: formation of bubbles, test item appears like white foam Approx. 185 °C: test item rose in the capillary, appears like white foam 200 °C: no further changes

 

Conclusion: The test item had a melting point of 154.1 °C, afterwards decomposition started.

Description of key information

154.1 °C at 1013 hPa (OECD 102, DSC)

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

154.1 °C

Additional information

Decomposition started directly after melting.