Aluminium triisopropanolate

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: limited documentation available for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Defined amounts of test substances were dissolved in distilled water and stirred for 4 hours at room temperature, followed by quantitative analytical investigation by gas chromatography to determine amount of free alcohol formed. Recalculation of degree of hydrolysis

GLP compliance:

no

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

Solution was filtered and filtrate was quantitatively analysed by gas-chromatographic method, by a method specifically developed for this purpose.

Details on test conditions:

In a 200 ml vessel, equipped with reflux condenser and stirrer 1 mmol of aluminium triisopropylate was added to a defined amount of water and stirred (600 rpm) for 4 hours at room temperature. The process was visually controlled and the solution thereafter was filtered to remove insolubles and the filtrate was quantitatively analysed for the amount of free alcohol formed.

Duration:

4 h

pH:

8.5

Temp.:

20

Initial conc. measured:

100 mmol/L

Number of replicates:

1

Positive controls:

no

Negative controls:

no

Statistical methods:

A series of different aluminium alkoholates have been measured using the developed method

Test performance:

Aluminium triisopropylate in lump dissolved immediately following addition to water, resulting in a white suspension.

Transformation products:

yes

No.:

#1

Details on hydrolysis and appearance of transformation product(s):

Isopropanol was followed by quantitative GC to determine degree of hydrolysis by comparing isopropanol formed versus theoretical amount of isopropanol formed upon complete hydrolysis.

% Recovery:

< 1.9

pH:

8.5

Temp.:

20 °C

Duration:

4 h

pH:

8.5

Temp.:

20 °C

DT50:

< 4 h

Type:

not specified

Details on results:

98.1% of theoretical amount isopropanol was found in the aqueous phase indicative of immediate hydrolysis of the test subsatnce upon contact with water. The pH was not controlled by buffer solutions but measured to be 8.5 at the end of the experiment.

Validity criteria fulfilled:

not applicable

Conclusions:

In this experiment it was shown that aluminium triisopropylate reacts instantaniously with water forming almost quantitatively isopropanol and aluminium 3+ species while a pH of 8.5 is established (concentration 1 mol/L).

Executive summary:

In this experiment it was shown that aluminium triisopropylate reacts instantaniously with water forming almost quantitatively isopropanol and aluminium 3+ species while a pH of 8.5 is established (concentration 1 mol/L). At this pH the aluminium species present are mainly

Al(OH)₄^-, Al(OH)₃and Al(OH)₂^{+ (see Langmuir et al. 2004, Issue paper on the environmental chemistry of metals, US EPA Contract #68 -C-02 -060) - the identity of aluminium3+ species was not determined in this experiment.}

Description of key information

Aluminium triisopropylate reacts instantaneously with water to form isopropanol and Al3+ species. The resulting pH being weakly alkaline indicates according to Langmuir et al. 2004 that Al3+ species formed are mainly Al(OH)4-, Al(OH)3 and Al(OH)2+ at pH 8.5.

Key value for chemical safety assessment

Half-life for hydrolysis:

4 h

at the temperature of:

20 °C

Additional information

Aluminium triisopropylate reacts instantaneously with water to form isopropanol and Al3+ species. The resulting pH being weakly alkaline indicates according to Langmuir et al. 2004 that Al3+ species formed are mainly Al(OH)4-, Al(OH)3 and Al(OH)2+ at pH 8.5.

Thus, aluminium triisopropylate is abiotically degradable and forms isopropanol being readily biodegradable as shown in the registration dossier of isopropanol submitted by the same lead registrant.