Sodium glyoxylate

Melting point / freezing point

Administrative data

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental starting date: 28 March 2017. Experimental completion date: 22 June 2017

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

differential scanning calorimetry

Test material

Test material information

Constituent 1

Reference substance name:

Sodium glyoxylate

EC Number:

220-298-8

EC Name:

Sodium glyoxylate

Cas Number:

2706-75-4

Molecular formula:

C2H2O3.Na

IUPAC Name:

sodium oxoacetate

Specific details on test material used for the study:

Identification: Safelink SPM-01
Appearance/Physical state: colorless to slightly yellow powder
Batch: G150201
Purity: 99.9%
Expiry date: not supplied
Storage conditions: room temperature, in the dark

Results and discussion

Melting / freezing point

Key result

Atm. press.:

101 kPa

Decomposition:

yes

Decomp. temp.:

195 °C

Any other information on results incl. tables

Thermographic Data

Thermal Event	Interpretation	Temperature (°C)
		Determination 1	Determination 2	Determination 3
Endotherm (broad)	Onset of unknown thermal event	139.15	139.1	140.96
Exotherm (sharp)	Approximate onset of decomposition	195.75	194.75	199.6

Overall result: approximate decomposition from 195 °C (468 K)

After heating to 400 °C, samples 1 and 3 had lost approximately 47 % of their original

weight.

Atmospheric pressure was 101 kPa for Determinations 1 and 2.

Discussion

Similar thermographic profiles were obtained using air and nitrogen atmospheres; this

indicated that the observed decomposition was probably thermal and not oxidative.

It was not definitively known what the broad endotherm starting at approximately 140 °C

was due to; it may have been the release of entrained water. Heating a sample to 200 °C,

cooling to 100 °C and reheating up to 250 °C demonstrated that the endotherm was there on

initial heating but not on the second time.

The endotherm was evidently not due to melting. This was because, after being heated up to

200 °C the residue was still a powder and showed no signs of melting. However, it had

become pale brown (pale orange under a nitrogen atmosphere) in color which suggested

decomposition had begun. At 400 °C, after the sharp exotherm, the residue was black (dark

brown under a nitrogen atmosphere) which suggested a significant degree of decomposition

had occurred.

As a result of broad endotherm just prior to the exotherm, the onset temperature of

decomposition could only be approximated. However, for the sample that was re-heated the

large, sharp exotherm was absent; instead only a small exotherm was present. Also, the

residue was only brown in color compared to black when then large exotherm was present.

Evidently, the cause of the endotherm had an impact on the exothermic decomposition of the

test item.

Applicant's summary and conclusion

Conclusions:

The test item has been determined to decompose from approximately 195 °C (468 K) at
101 kPa. As a result, no value for the melting point or boiling point of the test item could be
determined.

Executive summary:

Decomposition from approximately 195 °C (468 K) by differential scanning calorimetry, designed to be compatible with Method A.1 Melting/Freezing Temperature of Commission Regulation (EC) No 440/2008 of 30 May 2008, and Method 102 of the OECD Guidelines for Testing of Chemicals, 27 July 1995. As a result, no value for the melting point of the test item could be determined.