Fatty acids, C18-24, zinc salts

Explosiveness

Link to relevant study record(s)

Reference

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 the substance contains chemical groups associated with explosive properties which include oxygen, but the calculated oxygen balance is less than - 200

Description of key information

The substance Fatty acids, C18-24, zinc salts is considered to be void of any explosive properties.

Key value for chemical safety assessment

Explosiveness:

non explosive

Additional information

According to Regulation (EC) No 1907/2006, Annex VII, section 7.11, column 2, the study does not need to be conducted if there are no chemical groups associated with explosive properties present in the molecule. According to ECHA Guidance on information requirements and chemical safety assessment Chapter R.7a: Endpoint specific guidance (July 2017), this substance does not contain functional groups that are directly associated with explosive properties.

However, since oxygen is present in the molecule, the oxygen balance (OB) according to the following chemical reaction and mathematical equation (Lothrop et al) was calculated:

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

using the formula: OB = -1600 [2x +(y/2) -z] / molecular weight,

where: x = Number of carbon atoms, y = Number of hydrogen atoms, z = Number of oxygen atoms.

In the following, the calculations which are in accordance with the requirements set forth in the ECHA guidance are briefly described. The calculations performed for zinc stearate and tetracosanoic acid zinc salt are considered to be equally relevant for substance Fatty acids, C18-24, zinc salts.

Molecular formula (zinc stearate): Zn (C₁₈H₃₅O₂)₂

Molecular weight: 632.335 g/mol

OB=-1600[72+35-4]/ 632.335 = -260.621

Molecular formula (tetracosanoic acid zinc salt): Zn (C₂₄H₄₇O₂)₂

Molecular weight: 800.67 g/mol

OB=-1600[96 +47-4]/ 800.67 = -277.767

The absence of reactive groups in the structural formula and the oxygen balance being less than –200 indicate that the substance will not decompose violently under formation of gases or release of energy (and thus does not pose a risk for explosivity). Thus, testing does not need to be conducted and a negative result can be predicted.

Substance Fatty acids, C18-24, zinc salts is therefore considered to be void of any explosive properties. Finally, it is noted that despite the long-term use of substance Fatty acids, C1248, zinc salts, this substance is not classified for explosive properties according to UN transport regulations and derogation from testing is hereby applied for.

Justification for classification or non-classification

The substance Fatty acids, C18-24, zinc salts is considered to be void of any explosive properties.

According to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations, substance Fatty acids, C18-24, zinc salts does not have to be classified as explosive. According to the criteria of REGULATION (EC) No 1272/2008, substance Fatty acids, C18-24, zinc salts does not have to be classified and has no obligatory labelling requirement for explosivity.