2-(4-methylphenoxy)-N-(1H-pyrazol-3-yl)-N-[(thiophen-2-yl)methyl]acetamide

Explosiveness

Link to relevant study record(s)

Reference

Endpoint:

explosive properties of explosives

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental dates: 20-21 November 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to an internationally recognized method, and under GLP. No deviation was reported. The test substance is adequately characterised. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

UN Manual of Tests and Criteria: Part I: Classification procedures, test methods and criteria relating to explosives of Class 1

Version / remarks:

rev. 6 (2015), Appendix 6

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD 113 Screening test for thermal stability and stability in air

Version / remarks:

1981

GLP compliance:

yes (incl. QA statement)

Remarks:

Inspection 20-21 June 2017, signed on 04 September 2017

Specific details on test material used for the study:

Storage conditions: Ambient temperature (10 °C to 30 °C) in original glass bottle.
The test item was tested as received. No further preliminary treatment such as drying or milling was performed.

Parameter:

other: DSC screening test

Remarks:

J/g

Value:

591

Two DSC-measurements in closed glass crucibles with the test item showed an endothermal effect in the temperature range of 110 – 135 °C (consistent with the melting point of 117.6°C, determined in study PS20170238-1) and an exothermal effect in the temperature range of 250 – 470 °C with a maximum energy release of 591 J/g.

The results are summarized in the table below.

Assay	Weight / mg	Final temperature / °C	Temperature range / °C	Type of effect	Energy / J/g
1	14.18	500	105 – 130 250 – 470	Endothermal Exothermal	n.r. 552
2	12.48	500	110 – 135 250 – 450	Endothermal Exothermal	n.r. 591

n.r.: not relevant

Interpretation of results:

study cannot be used for classification

Conclusions:

The released energy is slightly more than 500 J/g. Further testing is required.

Executive summary:

The thermal stability of the test substance was tested, under GLP, according to UN MTC screening procedure/OECD 113 guideline, with Differential Scanning Calorimetry.

The determination was carried out in closed crucible under nitrogen, with a heating rate of 3 K/min. Duplicate results were consistent, with exothermal reaction observed between 250 and 470°C.

The maximum energy released was 591 J/g.

Description of key information

DSC screening test: exothermal reaction between 250 and 470°C, maximum energy 591 J/g.

Additional information

The substance was assessed according to UN MTC Appendix 6 screening procedure, relevant for CLP classification:

The chemical structure contains a N-N bond, as well as 1,2-diene, which are identified as alert structural features.

The Oxygen Balance was calculated as -198, which is very close, but above, the cut-off value of -200.

Therefore, a calorimetric test was conducted: a fully reliable, GLP, experimental study, is available, and is considered as a key study.

Justification for classification or non-classification

Based on screening procedures, as the exothermic decomposition energy is above the threshold of 500 J/g, the study is inconclusive for classification, according to CLP criteria.

Further testing should be required (i.e. test series 2b and 2c). However, it is deemed unnecessary, considering that the substance was tested as pure, i.e. solid, for registration purpose, but it is currently neither handled nor placed on the market under this form. The powder is manufactured in closed conditions, with immediate dilution in solvent. At the date of submission of this dossier, the substance is marketed as a 10% solution in ethyl lactate. Therefore, testing of the commercial product(s) is more relevant.

Moreover, as the exotherm observed for the pure substance was not sharp and high, but broad with energy release very close to the threshold value, this suggests rather a slow decomposition than a violent reaction. Under solution form, with ethyl lactate having no explosive potential, based on its structure, the energy is expected to be absorbed by the solvent, thus to fall below 500 J/g. So no high explosive potential is anticipated from the marketed solution.