Nickel bis(2-ethylhexanoate)

Dissociation constant

Administrative data

Endpoint:

dissociation constant

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

21 to 22 september 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 112 (Dissociation Constants in Water)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Nickel 2-ethylhexanoate

IUPAC Name:

Nickel 2-ethylhexanoate

Constituent 2

Reference substance name:

Nickel bis(2-ethylhexanoate)

EC Number:

224-699-9

EC Name:

Nickel bis(2-ethylhexanoate)

Cas Number:

4454-16-4

Molecular formula:

C8H16O2.1/2Ni

IUPAC Name:

nickel(2+) bis(2-ethylhexanoate)

Details on test material:

- Name of test material (as cited in study report): Nickel 2-ethylhexanoate (OCTNI BASE)
- Chemical formula of active ingredient: [CH3(CH2)3CH(C2H5)CO2]2Ni
- Molecular weight (if other than submission substance):

- Physical state: paste
- Content of Nickel: 15.92% (w/w)
- Lot/batch No.: L6302
- Expiration date of the lot/batch: 04 November 2010
- Storage condition of test material: room temperature
:

Results and discussion

Dissociating properties:

not determined

Any other information on results incl. tables

A pre-test was performed, in which the absorbance of an aqueous solution at half the water solubility was measured. The test item has a known maximum in n-hexane at 406 nm. This can also be observed in an aqueous solution. The OECD 112 guideline allows for testing up to half the water solubility which corresponds to 55 mg/L. The absorbance of the test item is about 0.009 to 0.010 AU.

The dissociation constant of Nickel 2-ethylhexanoate cannot be determined at this concentration, since the absorbance is too low to measure differences accurately. The other methods which are described in the OECD guideline 112 (titration or conductometric method) are also not suitable due the low water solubility of the test item.

Applicant's summary and conclusion

Conclusions:

Due to the low solubility and low absorbance of the test item, the dissociation constant cannot be determined at moderate pH values. Extreme pHs would destroy the complex. At low pH, the Ethyl-hexanoate will be protonated and therefore removed from the equilibrium. At high pH values, the Ni2+-ion will precipitate as hydroxide.