2-chloro-2-methylpropane

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Data waiving:

study technically not feasible

Justification for data waiving:

the study does not need to be conducted because the substance is hydrolytically unstable at pH 4, 7 and 9 (half-life less than 12 hours)

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2018-03-05 to 2018-03-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Key result

Remarks on result:

not determinable

Details on results:

During the water solubility experiments the two phase system of test item/water had changed into one phase. In the subsequent GC analysis of aliquots of the water solubility experiments the test item specific signal at 3.2 min could not be detected anymore. Instead of this a delayed signal at 3.4 min was found. According to literature (W. Klopffer Verhalten und Abbau von Umweltchemikalien, John Wiley & sons, 2012) the test item 2-chloro-2-methylpropane (synonym: t-Butylchlorid) hydrolyzes with a half-value time of (t1/2) = 109 s into t-butanol.

Therefore as reference pure t-butanol was dissolved in methanol and analyzed with the identical GC method as the present test item. Because of corresponding retention times of t-butanol and the hydrolysis product of the water solubility experiments of around 3.4 min, it was assumed that the test item undergoes hydrolysis during the water solubility experiments. Another indication of a hydrolysis of the test item into t-butanol and hydrochloric acid was the low pH value of 0.7 measured after the water solubility experiments.

For the test item 2-chloro-2-methylpropane no water solubility could be determined according to the flask method, as the test item hydrolyzes into 2-methylpropan-2-ol during the solubility experiments.

Water solubility experiments of the test item

Experiment	48 h experiment	72 h experiment	96 h experiment	Blank experiment (96 h)
Amount of test item /	2.89	2.89	2.90	--
Amount of demineralized water / mL	100	100	100	100
Stirring time at 20 °C / h	24	48	72	72
pH at 24 °C	0.7	0.7	0.7	5.5
Dilution factor	1000	1000	1000	1000
Measured concentration / mg/L	--	--	--	--

 

Conclusions:

For the test item 2-chloro-2-methylpropane no water solubility could be determined according to the flask method, as the test item hydrolyses into 2-methylpropan-2-ol during the solubility experiments.

Executive summary:

The water solubility was determined according to OECD 105 using the shake flask method with GC analysis. The preliminary test showed that the water solubility of the test item is > 10 mg/L. Thus, the water solubility was determined by the flask method. During the water solubility experiments the two phase system of test item/water had changed into one phase. In the subsequent GC analysis of aliquots of the water solubility experiments the test item could not be detected anymore. Therefore, as reference pure t-butanol was analysed with the GC method. Because of corresponding retention times of t-butanol and the hydrolysis product of the water solubility experiments, it was concluded that the test item undergoes hydrolysis during the water solubility experiments. Another indication of a hydrolysis of the test item into t-butanol and hydrochloric acid was the low pH value of 0.7 measured after the water solubility experiments. Thus, as the test item rapidly hydrolyses in water, no water solubility could be determined.

 

Description of key information

The substance decompose in contact with water.

Additional information

Data waiving [4.7.1]

In accordance with column 2 of REACH Annex VII the study does not need to be conducted as the test item decompose (hydrolyse) rapidly in contact with water. Thus, the determination of the water solubility is technically not feasible.

 

 

Supporting study [4.7-2]

The water solubility was determined according to OECD 105 using the shake flask method with GC analysis [reference 4.7 -2]. The preliminary test showed that the water solubility of the test item is > 10 mg/L. Thus, the water solubility was determined by the flask method. During the water solubility experiments the two phase system of test item/water had changed into one phase. In the subsequent GC analysis of aliquots of the water solubility experiments the test item could not be detected anymore. Therefore, as reference pure t-butanol was analysed with the GC method. Because of corresponding retention times of t-butanol and the hydrolysis product of the water solubility experiments, it was concluded that the test item undergoes hydrolysis during the water solubility experiments. This was supported by a hydrolysis study [reference 5 .1.2 -1]. Another indication of a hydrolysis of the test item into t-butanol and hydrochloric acid was the low pH value of 0.7 measured after the water solubility experiments. Thus, as the test item rapidly hydrolyses in water, no water solubility could be determined.