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Environmental fate & pathways

Hydrolysis

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Endpoint:
hydrolysis
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Reason / purpose for cross-reference:
data waiving: supporting information
Endpoint:
hydrolysis
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Principles of method if other than guideline:
Acceptable model on similar substance
GLP compliance:
no
Estimation method (if used):
USEPA (United States Environmental Protection Agency) HYDROWIN v1.67 (2000)
http://www.epa.gov/opptintr/exposure/
pH:
8.3
DT50:
> 1 000 000 yr

Appendix 1: Hydrowin v1.67 output

SMILES : C(F)(F)(F)C(F)C

CHEM   :

MOL FOR: C3 H4 F4

MOL WT : 116.06

--------------------------- HYDROWIN v1.67 Results ---------------------------

                         R2

                         |               X: -F   (Leaving halogen in R1)

ALKYL HALIDE:         R1-C-H            R1: -CF3               

                         |              R2: -F                 

                         R3             R3: -CH3               

 Kb hydrolysis at atom #  5:  7.057E-009  L/mol-sec

 Total Kb for pH > 8 at 25 deg C :  7.057E-009  L/mol-sec

 Kb Half-Life at pH 8: 3.112E+006  years 

 Kb Half-Life at pH 7: 3.112E+007  years 

   The rate constant estimated for the ALKYL HALIDE DOES NOT include the neutral hydrolysis rate constant!!

   For some alkyl halides, the neutral rate constant is the dominant hydrolysis rate at environmental pHs!

   If the neutral rate constant is important, the HYDRO estimated rate will under-estimate the actual rate!

Description of key information

Key value for chemical safety assessment

Additional information

Alkanes and alkenes are types of organic functional groups that are generally resistant to hydrolysis (Harris JC and Hayes MJ (1990). Rate of hydrolysis. In: Handbook of Chemical Property estimation Methods: Environmental Behaviour of Organic Compounds. Lyman WJ, Reehl WF and Rosenblatt DH (eds.), American Chemical Society, Washington DC, USA.). A hydrolysis rate constant was estimated for a surrogate analogue (CF3-CHF-CH3) [421-48-7] using the alkyl halides QSAR within HYDROWIN v2. With an estimated half-live in the range 106 to 107 years, the hydrolysis rate of this molecule without the double bond, is expected to be negligible. The presence of the -CF=CH2group in HFO-1234yf, instead of the -CHFCH3group in [421-48-7] for which the calculation was done, is not expected to have a major influence on the hydrolysis rate. Therefore, based on this structure-activity relationship, hydrolysis is not expected to be a relevant degradation mechanism for this substance.