2,4,6-trimethylcyclohex-3-enecarbaldehyde

Explosiveness

Administrative data

Endpoint:

explosive properties of explosives

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because there are no chemical groups present in the molecule which are associated with explosive properties

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
Explosive properties are associated with the presence of certain chemical groups in a molecule which can react to pro-duce very rapid increases in temperature or pressure (UN, 2009)1. Column 2 of REACH Annex VII provides the following specific rules for adaptation of the standard information requirement for explosive properties.

“The study does not need to be conducted if:

(1) there are no chemical groups associated with explosive properties present in the molecule, or
(2) the substance contains chemical groups associated with explosive properties which include oxygen and the calculated oxygen balance is less than -200, or
(3) the organic substance […] contains chemical groups associated with explosive properties, but the exothermic decom-position energy is less than 500 J/g and the onset of exothermic decomposition is below 500 °C, or [….]”

Screening procedures and waiving of testing are described in ECHA Guidance on the Application of the CLP Criteria.

Based on the above rules, the test substance is assessed in a tiered approach:

(1) In the absence of specific data on the explosivity of a test substance, its chemical structure is examined for the pres-ence of functional groups associated with explosive properties. These groups can be directly concerned with the explosive property or otherwise able to contribute to it. If the substance does not contain any groups associated with explosivity then a negative result is likely.

(2) If the substance contains chemical groups associated with explosivity, and if oxygen is present in the molecule, the oxygen balance (OB) is calculated according the following reaction scheme and mathematical equation:

CxHyOz + [x + (y/4) - (z/2)] O2 → x CO2 + (y/2) H2O

Using the formula:

Oxygen balance = -1600 [2x + (y/2)-z]/molecular weight;

If the oxygen balance is less than –200, then testing does not need to be conducted and a negative result can be pre-dicted.

The oxygen balance was developed for compounds containing only nitrate groups and it applies only to organic substanc-es. Extending its use to molecules with other oxygen containing groups should be done with care. As an example the presence of hydroxyl-groups will strongly affect the oxygen balance towards higher values, whereas this group does not contribute to explosive properties. In addition the presence of for instance halogens tends to decrease the flammability and explosivity but this is not accounted for.
(3) If groups associated with explosivity are present in the substance, and the oxygen balance is > -200, the substance may be further assessed by giving consideration to any experimental data indicating possible explosive behavior, namely differential scanning calorimetry (DSC) or differential thermal analysis (DTA) data.
From the structural formula of the test substance, it can be concluded that the substance is not explosive. The substance does not have the functional groups associated with explosive properties or chemical instability.

Therefore it can be concluded beyond reasonable doubt that the test substance is incapable of causing explosions by action of external heating sources. As such further testing is not needed.