Sodium amide

Auto flammability

Administrative data

Endpoint:

relative self-ignition temperature (solids)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Grewer-Oven-Test, VDI 2263-1

Principles of method if other than guideline:

The self-heating in air was studied in a screening test according to Grewer (Grewer-Oven-Test, VDI 2263-1). A wire basket (V = 8 cm') was heated in a preheated air stream and any temperature change in the sample centre was measured compared to an inert reference substance (graphite). The heating rate was 1.8 K/min.
In addition to the Grewer-Oven-Test with the pure substance a mixture with Kieselgur (1:1) was tested. Kieselgur prevents the meshes of the basket to be filled with swollen material: air can diffuse into the wire basket during the whole test. Additionally, Kieselgur prevents the wire basket from emptying due to melting of the product. In this case the self-heating of the product in contact with porous material with high specific surface e.g. insulation material or deposits is simulated.
The self-ignition temperature is the temperature at which the temperature rise rate of the test item exceeds the temperature rise rate of the reference (graphite) due to an exothermal effect.

GLP compliance:

yes

Remarks:

the laboratory is GLP certified, but the study was not GLP inspected

Test material

Test material information

Constituent 1

Reference substance name:

Sodium amide

EC Number:

231-971-0

EC Name:

Sodium amide

Cas Number:

7782-92-5

Molecular formula:

H2NNa

IUPAC Name:

sodium amide

Test material form:

solid: particulate/powder

Details on test material:

Natriumamid Pulver
Mat. Nr. 10046758
Batch Nr. GB56701
Purity: >99%

Results and discussion

Relative self-ignition temperature (solids)

Key result

Relative self-ignition temperature:

>= 90 °C

Any other information on results incl. tables

Due to the fact that the test item melts at ca. 210 °C, an aliquot of the test item was mixed with Kieselgur to prevent the wire basket from emptying. In the screening test with the Kieselgur mixture (1:1) an exothermal reaction was detected starting at 90 °C. Self-heating led to above 550 °C.

Applicant's summary and conclusion

Conclusions:

According to the guideline VDI 2263, sheet 1 (Grewer-Oven) self-ignition was observed at 90 °C.

Executive summary:

In the Grewer-Oven-Test with the Kieselgur mixture (1:1) an exothermal reaction was detected starting at 90 °C. In the DSC measurement (absence of air) an exothermal effect starting at 150 °C was observed.

Due to the fact that the exothermal reaction in the Grewer-Oven-Test started spontaneously it can be derived that the hegt production did not base an hydrolysis due to humidity. Conclusion: The presence of oxygen decreases the thermal stability of the test item.

According to TRAS 410 "Erkennen und Beherrschen exothermer Reaktionen" safe product handling in air is only possible significantly below ambient temperature (100 K safety margin to the self-heating of the Kieselgur mixture in the Grewer-Oven).

The danger of a self-ignition does not exist during the handling under inert conditions. Furthermore, the danger of a dust explosion can also be excluded under these conditions. In this case the product temperature may be raised to the limiting temperature Texo = 50 °C.

lt has to be noted that according to literature, the test item (sodium amide) reacts strongly exothermal with water (hydrolysis) forming sodium hydroxide and ammonia. In contact with oxygen explosive reaction products could be formed.
UN Transport Regulations: Due to the results from the Grewer-Oven-Test further tests are recommended to classify (or exclude) the test item as "self-heating substance" of class 4.2 according to the transport regulations.

EU-GHS/CLP: Due to the results from the Grewer-Oven-Test further tests are recommended to classify (or exclude) the test item as "self-heating substance" according to the EU-GHS/CLP regulations.