Aluminium ammonium bis(sulphate)

Stability: thermal, sunlight, metals

Administrative data

Endpoint:

stability: thermal, sunlight, metals, other

Remarks:

Migrated from section 'Stability: thermal, sunlight, metals'

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: The reference is only a graph (internal company data) with no experimental details.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

other company data

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 113 (Screening Test for Thermal Stability and Stability in Air)

Test material

Test material information

Constituent 1

Reference substance name:

Aluminium ammonium bis(sulphate)

EC Number:

232-055-3

EC Name:

Aluminium ammonium bis(sulphate)

Cas Number:

7784-25-0

Molecular formula:

Al.H3N.2H2O4S

IUPAC Name:

aluminium ammonium bis(sulphate)

Results and discussion

For thermal stability study

Test substance thermally stable:

yes

Operating temperature

Operating temp.:

25 - 1 400 °C

Any other information on results incl. tables

Between 25 and ca 200°C, the DSC trace shows four endotherm peaks (107.5°C, 128.3°C, 174.3°C and 212.6°C), and the TG trace decrease continuously to 53%, corresponding to the loss of crystallisation water.

Both traces remains stable up to ca 500°C. An endotherm and a loss of mass occur at 549°C. 40% TG is supposed to correspond to decomposition with release of NH3 +1/2 H2SO4 (or 1/2 H20 + 1/2 SO3).

Above 600°C, DSC slowly increase, with no significant peaks, but only two very small exotherms at 917°C and 1205°C. The maximum signal recorded was 1 mW/mg at 1400°C.

The TG trace decrease with a shoulder between ca 600°C and 900°C. At higher temperatures, the line is horizontal, with Al2O3 residue remaining after loss of SO3.

Applicant's summary and conclusion

Executive summary:

Combined Differential Scanning Calorimetry (DSC) and ThermoGravimetric Analysis (TGA) study on the substance showed that the substance undergoes thermal decomposition starting from its melting point, with first loss of crystallisation water. The anhydrous substance remains then stable between ca 200°C and 500°C, but is followed by NH3 and SO3 release. Aluminium oxide residue is obtained above 900°C.