Dibutyl hydrogen phosphate

Flammability

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

self-heating substances / mixtures

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Qualifier:

according to guideline

Guideline:

other: UN-MTC, Part II, test series A-H

Deviations:

no

GLP compliance:

no

The preliminary procedure results in a heat of decomposition of > 320 J/g. The onset of the exothermic reaction was 256°C. In the following SADT test, no exothermic effects were recorded. Heat release of the Dewar of 36.7 mW/kg*K is obtained in this test. Following the test criteria and the method of assessing results according to UN-MTC, test series H.4, the sample temperature does not exceed the test chamber temperature by 6°C. No exothermic effects were recorded and ∆T for the exothermic reaction is < 6°C. Thus, the SADT criterion (SADT </= 75°C) for a self-reactive substance is not meet.

Interpretation of results:

other: no self-reactive substance

Conclusions:

Following the procedure of the UN-MTC, section 28, test series A-H, an exothermic reaction of > 320J/g was detected at 256 °C in a preliminary procedure. Based on the outcome of this test, further testing was necessary and a heat accumulation storage test, according to UN-MTC, test series H.4 with Dewar vessels was conducted, resulting in a heat release of the Dewar of 36.7 mW/kg*K, as no exothermic effects were recorded. Thus, the SADT criterion (SADT

Executive summary:

In order to identify of whether dibutyl hydrogen phosphate meets the definition of a self-reactive substance, determinations were performed according to section 28, test series H of the UN-MTC. As recommended, a preliminary procedure was performed to determine the effect of heating under confinement in accordance with test series E. A differential thermal analysis (or DTA) with a heating rate of 3 K/min was carried out yielding a heat of decomposition of > 320 J/g. The onset of the exothermic reaction was 256°C. Based on the outcome of this test, further testing was necessary and a heat accumulation storage test, according to UN-MTC, test series H.4 with Dewar vessels was conducted. In this subsequent SADT test, no exothermic effects were recorded and a heat release of the Dewar of 36.7 mW/kg*K is obtained. Following the test criteria and the method of assessing results according to UN-MTC, test series H.4, the sample temperature does not exceed the test chamber temperature by 6°C. No exothermic effects were recorded and ∆T for the exothermic reaction is < 6°C. Thus, the SADT criterion (SADT </= 75°C) for a self-reactive substance is not meet and dibutyl hydrogen phosphate is not considered for classification in this class.

Reference 2

Endpoint:

substances / mixtures which in contact with water emit flammable gases

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the organic substance does not contain metals or metalloids and hence, the classification procedure does not need to be applied

Reference 3

Endpoint:

flammable solids

Data waiving:

study technically not feasible

Justification for data waiving:

the study does not need to be conducted because the substance is a liquid

Reference 4

Endpoint:

pyrophoric liquids

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is known to be stable in contact with air at room temperature for prolonged periods of time (days) and hence, the classification procedure does not need to be applied

Reference 5

Endpoint:

self-heating substances / mixtures

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is completely molten at 160°C

Description of key information

a) Flammability
A test on flammability is technically not possible, as the test substance is a liquid. The flammability of a liquid is described by the flash point.
b) Flammability on contact with water
Testing for flammability on contact with water does not need to be conducted as the substance contains no metals or metalloids and therefore will not release flammable gases in contact with water.
c) Pyrophoric properties
Testing for pyrophoric properties does not need to be conducted as it is scientifically unjustified. Based on experience during handling and use, no pyrophoric properties were observed and the structure does not give a reference to pyrophoric properties.
d) Self-heating properties
This class is only applicable to solids. As the substance is liquid at 20°C and has a melting point < 160°C and is completely molten up to this temperature, the substance has no self-heating behaviour. 
e) Self-reacting properties
Following the procedure of the UN-MTC, section 28, test series A-H, an exothermic reaction of > 320J/g was detected at 256 °C in a preliminary procedure. In a subsequent SADT test, no exothermic effects were recorded. Thus, the SADT criterion for a self-reactive substance is not meet.
d) Organic peroxide
In accordance with part 2, section 2.15 of Annex I of the CLP Regulation 1272/2008, the substance does not need to assessed for organic peroxid properties, as based on its chemical structure, the substance is not an organic peroxide.
e) Flammable aerosols
In accordance with section 2.3 of Annex I of the CLP regulation 1272/2008, a study on flammable aerosols does not need to be conducted, as the substance is a liquid with a flash point > 93°C, not including flammable liquids.
g) Gases under pressure
In accordance with part 2, section 2.5 of Annex I of the CLP Regulation 1272/2008, the hazard class gases under pressure does not apply to the substance, as the substance is liquid at 20°C at 1013 hPa.

Key value for chemical safety assessment

Flammability:

non flammable

Additional information

In order to identify of whether dibutyl hydrogen phosphate meets the definition of a self-reactive substance, determinations were performed according to section 28, test series H of the UN-MTC. As recommended, a preliminary procedure was performed to determine the effect of heating under confinement in accordance with test series E. A differential thermal analysis (or DTA) with a heating rate of 3 K/min was carried out yielding a heat of decomposition of > 320 J/g. The onset of the exothermic reaction was 256°C. Based on the outcome of this test, further testing was necessary and a heat accumulation storage test, according to UN-MTC, test series H.4 with Dewar vessels was conducted. In this subsequent SADT test, no exothermic effects were recorded and a heat release of the Dewar of 36.7 mW/kg*K is obtained. Following the test criteria and the method of assessing results according to UN-MTC, test series H.4, the sample temperature does not exceed the test chamber temperature by 6°C. No exothermic effects were recorded and ∆T for the exothermic reaction is < 6°C. Thus, the SADT criterion (SADT </= 75°C) for a self-reactive substance is not meet and dibutyl hydrogen phosphate is not considered for classification in this class.

Justification for classification or non-classification

Dibutyl hydrogen phosphate is not flammable, it has no pyrophoric properties, no flammability in contact with water, is not a self-heating and a self-reactive substance, is not an organic peroxide; and hence no classification according to both Directive 67/548/EEC and GHS (Regulation EC 1272/2008) is required.