Hydroxido potassium zirconium carbonate, where there are 0, 1 or 2 hydroxide groups and 2, 3 or 4 potassium atoms and 2, 3 or 4 carbonate groups.

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 January 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study not conducted to GLP but conducted in accordance with generally accepted scientific principles based on a standard OECD method.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Objective of study:

other: determination of the behaviour of the substance at low pH in order to provide comparison with the similar substance AZC.

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD 111

Deviations:

yes

Remarks:

The study was conducted at pH 2 and pH 4. Due to the very fast hydrolysis of the substance under acidic conditions and the slow release of CO2 from the solution, it was decided not to perform kinetic measurements.

Principles of method if other than guideline:

The purpose of this study was to determine the hydrolysis under evolution of carbon dioxide of Potassium Zirconium Carbonate (KZC) at pH 2.00
and pH 4.00. Gas absorption on sodium hydroxide (on a support material) is used to determine the cleavable amount of carbon dioxide from KZC in acidic solution at two different pH values.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Potassium Zirconium Carbonate

IUPAC Name:

Potassium Zirconium Carbonate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Results and discussion

Any other information on results incl. tables

RESULTS,  pH 2.00

 

Sample weight as is	Acid buffer solution volume	Temperature used to release the CO2from the solution	Reac- tion time	pH at the end of reaction (at room temperature)	CO3^2-con- tent in KZC (according to supplier)	CO2 found in absorption tube	CO3^2-calculated from CO2 found	CO3^2- content in KZC sample
[g]	[mL]	[°C]	[min]		[%]	[g]	[g]	[%]
0.3061	250.0	25	40	2.00	44.9	0.0956	0.1304	42.59
0.3068	250.0	25	40	2.00	44.9	0.0960	0.1309	42.67
0.3070	250.0	25	40	2.00	44.9	0.0954	0.1301	42.37
0.3110	250.0	25	40	2.00	44.9	0.0975	0.1329	42.75

The amount of CO₂ found after hydrolysis is equal to a carbonate content of 42.6 ± 0.1 % in KZC tested substance.

RESULTS,  pH 4.00

 

Sample weight as is	Acid buffer solution volume	Temperature used to release the CO2from the solution	Reac- tion time	pH at the end of reaction (at room temperature)	CO3^2-con- tent in KZC (according to supplier)	CO2 found in absorption tube	CO3^2-calculated from CO2 found	CO3^2- content in KZC sample
[g]	[mL]	[°C]	[min]		[%]	[g]	[g]	[%]
0.3043	250.0	65 - 70	80	4.10	44.9	0.0919	0.1253	41.18
0.3068	250.0	65 - 70	80	4.10	44.9	0.0990	0.1350	44.00
0.3085	250.0	65 - 70	80	4.10	44.9	0.0938	0.1279	41.46

 

The amount of CO₂ found after hydrolysis is equal to a carbonate content of 42.2 ± 1.3 % in KZC tested substance.

IDENTIFICATION OF HYDROLYSIS PRODUCTS

One hydrolysis product of KZC is carbon dioxide. The remaining zirconium compounds are not identified.

Applicant's summary and conclusion

Conclusions:

The experiments at pH 2 and 4 show fast hydrolysis of KZC. This hydrolysis is observed via effervescence during addition of the acidic buffer solution. The fast hydrolysis and the fact that the CO2 release from the solution is slow did not allow kinetic information to be obtained. The experiments showed that the CO2 released during the hydrolysis reaction corresponds to the carbonate content of KZC as given by the supplier. Based on this information, it can be concluded that KZC undergoes complete degradation under acidic conditions in a few minutes.

Executive summary:

A study was conducted to investigate the hydrolysis of the test material under acidic conditions, broadly in accordance with OECD guideline 111.

Gas absorption on sodium hydroxide (on a support material) is used to determine the cleavable amount of carbon dioxide from KZC in acidic solution at two different pH values.

The experiments at pH 2 and 4 show fast hydrolysis of KZC. This hydrolysis is observed via effervescence during addition of the acidic buffer solution. The fast hydrolysis and the fact that the CO2 release from the solution is slow did not allow kinetic information to be obtained. The experiments showed that the CO2 released during the hydrolysis reaction corresponds to the carbonate content of KZC as given by the supplier. Based on this information, it can be concluded that KZC undergoes complete degradation under acidic conditions in a few minutes.