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Environmental fate & pathways

Hydrolysis

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Description of key information

For Cyclacet the estimated half-life for hydrolysis is > 1 year for pH 4 and 7; for pH 9 the half life is 13 days based on information from Cyclobutanate which was tested in an OECD TG 111 study.

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
25 °C

Additional information

For Cyclacet no experimental hydrolysis information is available, this information can be retrieved from Cyclobutanate using read across. First the experimental information of Cyclobutanate is presented and thereafter the read across justification to use this information for Cyclacet

Cyclobutanate experimental hydrolysis information

For assessing hydrolysis of Cyclobutanate a test according to OECD TG 111 was performed with the following results. At pH 4 and 7 the estimated half-lives at 25oC are > 1 year. At pH 9 at 25oC the estimated half-life is 13 days.

Cyclacet and its hydrolysis as function of pH using read across information from Cyclobutanate

Introduction and hypothesis for the analogue approach

Cyclacet is an acetic ester attached to a tricyclodecenyl fused ring structure. For this substance no experimental hydrolysis data is available. In accordance with Article 13 of REACH where is presented that lacking information can be generated by means other than experimental testing such as SARs, grouping and read-across, the data gap of Cyclacet is filled by using read across from the analogue Cyclobutanate.

Hypothesis: Cyclacet is expected to have the same hydrolysis properties as its analogue Cyclobutanate.

Available experimental information:For Cyclobutanate a well conducted hydrolysis test (OECD TG 111, Klimisch 1) is available. The obtained data showed thatthe estimated half-life for hydrolysis is > 1 year for pH 4 and 7, and for pH 9 the half-life is 13 days.

Target chemical and source chemical(s)

Chemical structures of the target chemical Cyclacet and the source chemical Cyclobutanate are shown in the data matrix, including relevant physico-chemical properties.

Purity / Impurities

Cyclacet is a reaction masses containing a mixture of two very similar isomers (5-yl and 6-yl). The impurities are all below 1%.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation, which is presented below.

Analogue justification: For Cyclacet the analogue Cyclobutanate is selected based on similarity in chemical structure and because for Cyclobutanate hydrolysis information is available.

Structural similarities and differences:The target and the source chemical both have a tricyclodecenyl fused ring structure with an unsaturated bond in the outside ring, which can be on the 5yl or 6 yl position. On the other side of the ring an ester bond is attached with a short alkyl chain. The alkyl chain of Cyclacet is an ethyl chain while the source Cyclobutanate has a butyl chain.

Hydrolysis:The ethyl ester of Cyclacet versus the butyric ester group of Cyclobutanate is expected to be similarly (in)sensitive to hydrolysis. The protrusive effect, favourable for hydrolysis, of the two additional CH2 groups in the alkyl chain of Cyclobutanate, is expected to be minimal and therefore the same hydrolysis results of Cyclobutanate will be used for Cyclacet.

Uncertainty of the prediction:There or no remaining uncertainties other than those already addressed above.

Conclusions on the hydrolysis of Cyclacet

For Cyclacet no hydrolysis information is available. For Cyclobutanate, a related analogue, such information is present, which can be used for read-across. When using read across the result derived should be applicable for C&L and/orrisk assessment and be presented with adequate and reliable documentation.The current document fulfils this documentation.The estimated Cyclobutanate half-life for hydrolysis is > 1 year at pH 4 and 7 and 13 days at pH 9. Based on similarities in structure and physico-chemical properties, the same values can be used for Cyclacet.

Final conclusion: For Cyclacetthe estimated half-life for hydrolysis is > 1 year for pH 4 and 7 and for pH 9 the half-life is 13 days

 

Data matrix to support the read across to Cyclacet from Cyclobutanate on hydrolysis

Common names

Cyclacet

Target

Cyclobutanate

Key source

Chemical structures

Cas no 5-yl

Cas no of the generic

2500-83-6

54830-99-8

1361017-07-3

113889-23-9

Empirical formula

C12H16O2

C14H20O2

EINECS

911-369-0

441-420-8

REACH registered

Registered

Registered

Molecular weight

192

220

Physico-chemical data

 

 

Physical state

liquid

liquid

Melting point (°C)

< -20

< -20

Boiling point (°C)

247

275

Water solubility (mg/l)

186

11.5

Log Kow

3.9 (HPLC, OECD TG 117)

4.48 (Shake-flask, OECD TG 107)

Environmental Fate

 

 

Hydrolysis

RA Cyclobutanate

Half-life:

pH 4: > 1 year

pH 7: > 1 year

pH 9: 13 days