Tetrahydro-4-methylphthalic anhydride

Distribution modelling

Administrative data

Endpoint:

distribution modelling

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference Type:

other: SIDS initial assessment report

Title:

SIDS initial assessment report for SIAM15 tetrahydromethyl -1,3-isobenzofuranedione

Author:

Katsuo K.

Year:

2002

Bibliographic source:

SIDS initial assessment report

Materials and methods

Model:

calculation according to Mackay, Level III

Calculation programme:

Mackay, level III

Release year:

2 001

Media:

air - biota - sediment(s) - soil - water

Test material

Test material information

Constituent 1

Reference substance name:

Tetrahydromethylphthalic anhydride

EC Number:

234-290-7

EC Name:

Tetrahydromethylphthalic anhydride

Cas Number:

11070-44-3

IUPAC Name:

3a-methyl-3a,4,5,6-tetrahydro-2-benzofuran-1,3-dione

Details on test material:

- Molecular formula (if other than submission substance): C9 H10 O3
- Molecular weight (if other than submission substance): 166.18
- Smiles notation (if other than submission substance): O=C(OC(=O)C1CC=C(C2)C)C12
- InChl (if other than submission substance): 1/C9H10O3/c1-5-2-3-6-7(4-5)9(11)12-8(6)10/h2,6-7H,3-4H2,1H3
- Structural formula attached as image file (if other than submission substance): see Fig. (11070-44-3 structure.png)

Study design

Test substance input data:

MTHPA dissociation substance
- Molar mass: 184.19
- Data temperature: 25 degree C
- Water solubility: 10500 g/m3
- Vapour pressure:1.75E-3
- log Pow: 1.28

- Reaction half-life estimates for
- Air: 10.04
- Water: 240000
- Soil: 240000
- Sediment: 240000

Environmental properties:

to water

Results and discussion

Percent distribution in media

Air (%):

0

Water (%):

99.5

Soil (%):

0

Sediment (%):

0.5

Susp. sediment (%):

0

Biota (%):

0

Aerosol (%):

0

Any other information on results incl. tables

Tetrahydromethyl-1,3-isobenzofuranedione is considered to be hydrolyzed to 3-methyl-4(or 3)-cyclohexene-1,2-dicarboxylic acid and/or 4-cyclohexene-1,2-dicarboxylic acid in environment. So, the potential environmental distribution of 4-methyl-4-cyclohexene-1,2-dicarboxylic acid (one of the hydrolysate of tetrahydromethyl-1,3-isobenzofuranedion) obtained from a generic level III fugacity model is shown below:

-------------------------------------------------------------------------

Compartment  Release      Release       Release
            100% to air  100% to water 100% to soil

-------------------------------------------------------------------------

Air            0.0 %        0.0 %         0.0 %
Water        31.6 %       99.5 %        26.9 %
Soil          68.3 %        0.0 %        72.9 %
Sediment      0.2 %        0.5 %         0.1 %

For details on results see attachment.

Applicant's summary and conclusion

Executive summary:

It is confirmed that tetrahydromethyl-1,3-isobenzofuranedione hydrolyzes to the corresponding di-carboxylic acid in water.

Therefore, this substance is considered to be hydrolyzed to the corresponding di-carboxylic acids in the environment. These hydrolysis products are considered to be stable in the water phase. The potential environmental distribution of 4-methyl-4-cyclohexene-1,2-dicarboxylic acid (one of the representative hydrolysis product of tetrahydromethyl-1, 3-isobenzofuranedion) is obtained from a generic fugacity model level III relevant for the following figures:

-------------------------------------------------------------------------

Compartment  Release      Release       Release
            100% to air  100% to water 100% to soil

-------------------------------------------------------------------------

Air            0.0 %        0.0 %         0.0 %
Water        31.6 %       99.5 %        26.9 %
Soil          68.3 %        0.0 %        72.9 %
Sediment      0.2 %        0.5 %         0.1 %

For details on results see attachment.