Registration Dossier

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Physical and chemical properties

 

Dipotassium oxide/Potassium oxide


1.Appearance

Potassium oxide is yellowish white to grey hygroscopic crystalline powder.

 

 2.Melting point

Using the EPI Suite Mpbwin (v.1.43) QSAR model, a Melting Point of 302.03 deg C (Mean Value) was established.

 

3.Boiling point

Using the EPI Suite Mpbwin (v.1.43) QSAR model, a Boiling Point of  691.46 deg C (estimated) was established.

 

4.Specific gravity

2.32

 

5.Vapour pressure

A QSAR method predicts the vapour pressure of this substance to be  3.03E-014 Pa at 25C.

 

6.Water solubility

1000000 mg/l(calculated)

Substance is predicted by QSAR method to be very soluble ( 1000000 mg/l) with water

Substance is predicted by QSAR method (EPI Suite v 4.1/WSKOW v1.42 ) to be very soluble ( 1e+006 mg/l) in water.

 

 

7.Partition co-efficient

 

A reliable QSAR method predicts a value for the partition co-efficient (logKow) of -5.08 for this substance.

 

 

8.Hydrolysis as a function of pH

 

Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions.

Hydrolysis is a chemical reaction during which molecules of water (H2O) are split into hydrogen cations (H+, conventionally referred to as protons) and hydroxide anions (OH−) in the process of a chemical mechanism).

Potassium oxide is a basic oxide and reacts with water violently to produce the caustic potassium hydroxide

When water is added to  Potassium oxide, KOH is produced.

K2O+H2O→KOH

 

On this basis, Potassium oxide does not have a potential for Hydrolysis and Potassium ion will not hydrolise.

 

 9.Adsorption/desorption

KOCWIN predicts a Koc value of 13.22 L/kg (log Koc 1.1211) .The adsorption coefficient (Koc) was estimated using the KOCWIN v2.00 QSAR model available from the US EPA. The estimated adsorption coefficient was 13.22 L/kg (log Koc 1.1211)

 10.Dissociation constant

Potassium oxide Reacts violently with water.When water is added to Potassium oxide, Potassium hydroxide is produced.

K2O+H2O→KOH

 

Therefore testing for Dissociation constant does not need to be performed.

 

11.Flammability

From the compositional description and the structural formula given, it can be concluded that this substance CAS 12136-45-7 , (EINECS) 235-227-6 is not pyrophoric (will not ignite or emit flammable gases on contact with air, damp air, or water) nor does it exhibit the property of flammability (will not easily burn when ignited or contribute to the combustion of other materials). There are no functional groups or other structural alerts present that would support any concern that this substance should be classified as dangerous according to the criteria for evaluating flammability, which is furthermore confirmed by long term handling experience.

 

12.  Flash point

Potassium oxide is inorganic substance and according“ ANNEX VII - STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF ONE TONNE OR MORE” the study does not need to be conducted if the substance is inorganic.

 

 

13.Explosiveness

From the compositional description and the structural formula given, it can be concluded that this substance CAS 12136-45-7 , (EINECS) 235-227-6 does not exhibit explosive properties (will not detonate or deflagrate, under conditions of excessive heating with or without confinement, impact, or friction to produce heat and or gas). There are no functional groups or other structural alerts associated with explosive properties or tendencies that would indicate that this substance will manifest explosive properties. Similarly, the calculated Oxygen Balance is less than -200 suggesting that testing need not be conducted and that a negative result can be predicted. Thus, this substance should not be classified as dangerous according to the criteria for explosivity, which is furthermore confirmed by long term handling experience.

 

 

14.Viscosity

Dipotassium oxide/ Potassium oxide is solid which remains solid at temperatures significantly above room temperature.

OECD Test Guideline 114 on the viscosity of liquids indicates that the substance to be tested must be liquid at room temperature, and therefore a study of the viscosity of Dipotassium oxide/ Potassium oxide is not required.

   

15.Autoignition temperature

From the compositional description, the structural formula given, it can be concluded that it is not necessary to evaluate the ignition temperature of this substance by either the Self- or Auto-Ignition testing criteria indicated in the TGD. There are no functional groups or other structural alerts present that indicate that this substance would spontaneously ignite in air when exposed to a hot surface and thus should not be classified as dangerous with respect to this endpoint. This empirical evaluation is furthermore confirmed by long term handling experience. The study is therefore considered scientifically unjustified.

Therefore testing for Auto flammability does not need to be performed.

  

16.Oxidizing properties

 

From the compositional description and the structural formula given, it can be concluded that this substance CAS 12136-45-7, (EINECS) 235-227-6 does not exhibit oxidizing properties (will not cause or contribute to the combustion of other materials by virtue of its own inherent oxidation or reduction potential). There are no functional groups or other structural alerts present that would indicate that this substance would promote oxidation and thus should not be classified as dangerous according to the criteria for evaluating oxidizing properties. Furthermore, this is confirmed by long term handling experience.

 

 

 

 Table    Summary of physico-chemical properties

 

Property

Value

References

Physical state

Solid

Lide 90nd Edition,2009

Substance type

Inorganic

Lide 90nd Edition,2009

Color

Pale yellow

Lide 90nd Edition,2009

Molecular Weight

94.196g/mol

US EPA, 2011

Melting point

302.03°C (calculated)

USEPA, 2011

 

Boiling point

691.46°C (calculated)

USEPA, 2011

 

Vapour pressure

3.03E-014 Pa at 25C

USEPA, 2011

Water solubility

1000000 mg/l(mg/l (calculated) 

 

 US EPA, 2011

 

Partition coefficient n-octanol/water (log value)

log Kow=-5.08(calculated)

USEPA, 2011

 

Henry Law Constant

2.814E-023 atm-m3/mole (2.851E-018 Pa-m3/mole)

USEPA, 2011