O-isopropyl ethylthiocarbamate

Phototransformation in air

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

phototransformation in air

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR prediction

Qualifier:

no guideline required

Principles of method if other than guideline:

QSAR model, EPI Suite v 4.1/Aopwin v1.92

GLP compliance:

no

Remarks:

not applicable

Estimation method (if used):

PHOTOCHEMICAL REACTION WITH OH RADICALS - assumed reaction conditions used in model:
- Concentration of OH radicals:1.5E6 per cm3
- Temperature for which rate constant was calculated: 25C
- Computer programme: AOPWIN v1.92

Light source:

sunlight

Preliminary study:

Using the AOPWIN QSAR model, the photochemical degradation rate of O-isopropyl ethylthiocarbamate in the atmosphere is 45.7698 E-12cm3/molecule-sec, with a resultant predicted half live of 2.804 Hrs ( 0.234 Days (12-hr day; 1.5E6 OH/cm3))
OVERALL OH Rate Constant = 45.7698 E-12 cm3/molecule-sec
HALF-LIFE = 0.234 Days (12-hr day; 1.5E6 OH/cm3)
HALF-LIFE = 2.804 Hrs

Reaction with:

OH radicals

Rate constant:

0 cm³ molecule-1 s-1

Transformation products:

no

Results with reference substance:

OVERALL OH Rate Constant = 45.7698 E-12 cm3/molecule-sec
HALF-LIFE = 0.234 Days (12-hr day; 1.5E6 OH/cm3)
HALF-LIFE = 2.804 Hrs

Hydrogen Abstraction = 13.2698 E-12 cm3/molecule-sec

Reaction with N, S and -OH = 32.5000 E-12 cm3/molecule-sec

Addition to Triple Bonds = 0.0000 E-12 cm3/molecule-sec

Addition to Olefinic Bonds = 0.0000 E-12 cm3/molecule-sec

Addition to Aromatic Rings = 0.0000 E-12 cm3/molecule-sec

Addition to Fused Rings = 0.0000 E-12 cm3/molecule-sec

 

OVERALL OH Rate Constant = 45.7698 E-12 cm3/molecule-sec

HALF-LIFE = 0.234 Days (12-hr day; 1.5E6 OH/cm3)

HALF-LIFE = 2.804 Hrs

Validity criteria fulfilled:

yes

Remarks:

The photochemical degradation rate of O-isopropyl ethylthiocarbamate in the atmosphere is 45.7698 E-12 cm3/molecule-sec, with a resultant predicted half live of 2.804 Hrs (0.234 Days (12-hr day; 1.5E6 OH/cm3)

Conclusions:

Using the AOPWIN QSAR model, the photochemical degradation rate of O-isopropyl ethylthiocarbamate in the atmosphere is 45.7698 E-12cm3/molecule-sec, with a resultant predicted half live of 2.804 Hrs ( 0.234 Days (12-hr day; 1.5E6 OH/cm3))

Executive summary:

Using the AOPWIN QSAR model, the photochemical degradation rate of O-isopropyl ethylthiocarbamate in the atmosphere is 45.7698 E-12cm3/molecule-sec, with a resultant predicted half live of 2.804 Hrs ( 0.234 Days (12-hr day; 1.5E6 OH/cm3))

Reference 2

Endpoint:

phototransformation in air

Data waiving:

other justification

Justification for data waiving:

other:

Description of key information

Using the AOPWIN QSAR model, the photochemical degradation rate of O-isopropyl ethylthiocarbamate in the atmosphere is 45.7698 E-12cm3/molecule-sec, with a resultant predicted half live of 2.804 Hrs ( 0.234 Days (12-hr day; 1.5E6 OH/cm3))
If released to air, a vapor pressure of  0.68mm Hg at 25 deg C (0.68 mm Hg is equivalent to vapour pressure of  90.7 Pa ) indicates that O-isopropyl ethylthiocarbamate  (IPETC ) will exist solely as a vapor in the atmosphere. Vapor-phase O-isopropyl ethylthiocarbamate will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 0.234 days, calculated from its rate constant of  45.7698 E-12 cm3/molecule-sec at 25 deg. 
O-isopropyl ethylthiocarbamate  (IPETC)  do not contain chromophores that absorb at wavelengths >290 nm and therefore O-isopropyl ethylthiocarbamate  (IPETC ) is not expected to be susceptible to direct photolysis by sunlight.
 

Key value for chemical safety assessment

Half-life in air:

0.234 d

Degradation rate constant with OH radicals:

0 cm³ molecule-1 s-1

Additional information

Using the AOPWIN QSAR model, the photochemical degradation rate of O-isopropyl ethylthiocarbamate in the atmosphere is 45.7698 E-12cm3/molecule-sec, with a resultant predicted half live of 2.804 Hrs ( 0.234 Days (12-hr day; 1.5E6 OH/cm3))

OVERALL OH Rate Constant = 45.7698 E-12 cm3/molecule-sec

HALF-LIFE = 0.234 Days (12-hr day; 1.5E6 OH/cm3)

HALF-LIFE = 2.804 Hrs

If released to air, a vapor pressure of 0.00000000288mm Hg at 25 deg C (0.00000000288mm Hg is equivalent to vapour pressure of 3.84E-007 Pa ) indicates thatSodium Isopropyl Xanthate (SIPX) will exist solely as a vapor in the atmosphere. Vapor-phase Sodium Isopropyl Xanthate (SIPX) will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 0.879 days, calculated from its rate constant of 12.1686 E-12 cm3/molecule-sec at 25 deg.

Xanthates do not contain chromophores that absorb at wavelengths >290 nm and thereforeSodium Isopropyl Xanthate (SIPX) is not expected to be susceptible to direct photolysis by sunlight.