Registration Dossier

Administrative data

Endpoint:
phototransformation in air
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: The result is sourced from secondary literature.

Data source

Reference
Reference Type:
review article or handbook
Title:
Kinetics of the Gas-Phase Reactions of a Series of Organosilicon Compounds with OH and NO3 Radicals and O3 at 297 + 2 K
Author:
Atkinson R
Year:
1991
Bibliographic source:
Environ. Sci. Technol. 25(5):863-866

Materials and methods

Principles of method if other than guideline:
Method: other (measured)
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Hexamethylcyclotrisiloxane (CAS No. 541-05-9)
Purity: 85% (degassed under vacuum prior to use)

Study design

Details on test conditions:
Sensitiser (for indirect photolysis): other: OH, NO3 and O3

Results and discussion

Any other information on results incl. tables

Rate constant (cm3/molecule*sec): 
OH : 5.2 x 10E-13  
NO3: < 2 x 10E-16  
O3:  < 3 x 10E-20

The NO3 radical and O3 reactions are of no importance as tropospheric removal processes for this compound. The dominant gas-phase chemical loss process is by reaction with the OH radical.

Tropospheric concentration of OH radicals 7.7 E05 molecule/cm3over 24 -h period used to calculate half lives.

Calculated half-life of 20 days.

Applicant's summary and conclusion

Conclusions:
The NO3 radical and O3 reactions are of no importance as tropospheric removal processes for this compound. The dominant gas-phase chemical loss process is by reaction with the OH radical, with calculated half-life of 20 days.