Methenamine

Phototransformation in air

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in air

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Study period:

1996

Reliability:

1 (reliable without restriction)

Qualifier:

no guideline followed

Principles of method if other than guideline:

Estimated by calculation (AOPWIN)

GLP compliance:

no

Estimation method (if used):

AOPWIN (Atmospheric Oxidation Rate Program(R)) Program, Version 1.75, Syracuse Research Corporation, Merrill Lane, Syracuse, New York, 13210, USA, 1995

Details on light source:

not applicable

Details on test conditions:

not applicable

Reference substance:

no

Preliminary study:

not applicable

Test performance:

not applicable

Key result

DT50:

45 min

Test condition:

QSAR calculation

Results with reference substance:

no reference substance

In the atmosphere, methenamine is expected to be degraded by photochemical processes. The photooxidation of methenamine is estimated using the model AOPWIN with 0.87 * 10^-10cm³molecules^-1sec^-1. Assuming a mean atmospheric concentration of 5 * 10⁵OH^-radicals/cm³, the calculated half-life in the atmosphere is 45 min The estimation method for the gas-phase reaction with ozone was not applicable to hexamethylenetetramine.

Validity criteria fulfilled:

not applicable

Conclusions:

In the atmosphere, methenamine is expected to be degraded by photochemical processes with a half life of < 1 hour.

Executive summary:

In the atmosphere, methenamine is expected to be degraded by photochemical processes. The photooxidation of methenamine is estimated using the model AOPWIN with 0.87 * 10^-10cm³molecules^-1sec^-1. Assuming a mean atmospheric concentration of 5 * 10⁵OH^-radicals/cm³, the calculated half-life in the atmosphere is 45 min (Becher 1996). The half-life of 45 minutes can be used as a worst case input for the exposure assessment at the continental and regional scale. From the spectroscopic data available for methenamine, direct photolysis is not expected.

Description of key information

In the atmosphere, methenamine is expected to be degraded by photochemical processes with a half life of < 1 hour.

Additional information

In the atmosphere, methenamine is expected to be degraded by photochemical processes. The photooxidation of methenamine is estimated using the model AOPWIN with 0.87 * 10^-10 cm³ molecules^-1 sec^-1. Assuming a mean atmospheric concentration of 5 * 10⁵ OH^-radicals/cm³, the calculated half-life in the atmosphere is 45 min (Becher 1996). The half-life of 45 minutes can be used as a worst case input for the exposure assessment at the continental and regional scale. From the spectroscopic data available for methenamine, direct photolysis is not expected.