Didecyldimethylammonium chloride

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 Feb, 1997 - 10 Mar, 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Version / remarks:

Cited as Directive 84/449/EEC, C.10

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

At each sampling time 25 mL of sample was taken with a pipette and transferred into a 250 mL beaker. The samples were stored in the refrigerator or immediately subjected to the analytical procedure. The temperature of the thermostatic water bath was checked at least at the start and end of the tests and at each sampling time.

Buffers:

pH = 4.0: 100 mL of 0.5 M potassium hydrogen phtalate and 0.8 mL 0.5 M NaOH made up to 1 L with deionized water
pH = 7.0: 100 mL of 0.5 M potassium hydrogen phosphate and 5.92 mL 5 M NaOH made up to 1 L with deionized water
pH = 9.0: 100 mL of 0.5 M boric acid, 100 mL of 0.5 M potassium chloride and 100 mL 4.32 M NaOH made up to 1 L with deionized water

Details on test conditions:

-Temperature: 49.9 – 50.1°C
-pH: 4,7 and 9 and the pH changes were always less than 0.05 pH units for each level
-Duration of the test: 7220 min (= 120 h = 5 d)
- Number of replicates:2

Duration:

120 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

ca. 3.509 mg/L

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

ca. 3.939 mg/L

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

ca. 2.68 mg/L

Number of replicates:

2 at pH 4 and 7 and 4 at pH 9

Preliminary study:

Yes, preliminary test was also definite test because of the outcome.

Transformation products:

not specified

Key result

pH:

4

Temp.:

20 °C

DT50:

>= 1 yr

Key result

pH:

7

Temp.:

20 °C

DT50:

>= 1 yr

Key result

pH:

9

Temp.:

20 °C

DT50:

>= 1 yr

The test material showed less than 10% degradation after five days at 50 deg.C in all three tested pH. It is concluded that DDAC is hydrolytically stable at pH 4.0, 7.0 and 9.0 with a half-life equal or greater than a year at ambient temperatures.

Validity criteria fulfilled:

yes

Conclusions:

The substance is hydrolytically stable, with a DT50 equal to or greater than one year.

Executive summary:

The hydrolytic stability of the test substance was determined according to EU Method C7.The substance was kept in buffer solutions at pH 4.0, 7.0 and 9.0 in a water bath at 50°C for 5 days. Samples were taken at test start, then at regular intervals afterwards to determine half-life. If t1/2 was less than 2.4 h, or if less than 10% of the test substance was hydrolysed in 5 days, then no further test needed to be performed at that pH.The test substance showed less than 10% degradation after 5 days at 50°C for all three pH values. It was therefore considered hydrolytically stable at pH 4.0, 7.0 and 9.0, with a half-life equal to or greater than one year at ambient temperature (Geurts and Van Wijk, 1997).

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

20 °C

Additional information

The hydrolytic stability of the test substance was determined according to EU Method C7. The substance was kept in buffer solutions at pH 4.0, 7.0 and 9.0 in a water bath at 50°C for 5 days. Samples were taken at test start, then at regular intervals afterwards to determine half-life. If t1/2 was less than 2.4 h, or if less than 10% of the test substance was hydrolysed in 5 days, then no further test needed to be performed at that pH. The test substance showed less than 10% degradation after 5 days at 50°C for all three pH values. It was therefore considered hydrolytically stable at pH 4.0, 7.0 and 9.0, with a half-life equal to or greater than one year at ambient temperature (Geurts and van Wijk, 1997).