Reaction mass of methyl acetate and methanol

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance has a low octanol water partition coefficient and the adsorption potential of this substance is related to this parameter

Reference 2

Endpoint:

adsorption / desorption: screening

Remarks:

adsorption

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The adsorption of methanol onto different soil types was studied at 6°C by use of a batch procedure.

GLP compliance:

no

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

yes

Test temperature:

6°C

Analytical monitoring:

no

Key result

Type:

Koc

Value:

>= 0.13 - <= 0.61 L/kg

Validity criteria fulfilled:

not applicable

Conclusions:

The Koc for the test item ranged between 0.13 and 0.61for different soil types and concentrations.

Executive summary:

The adsorption of methanol onto three different soil types was messured at 6 °C. Only slight methanol adsorption occurred with the two sandy soils tested (percentage organic matter of 0.09% and 0.1% in the samples) and with the clay soil (percentage organic matter was 0.22%). Methanol solutions of concentration 0.1, 1.0, 9 and 90 mg/L were used in 1 hour exposure adsorption studies and adsorption coefficients of between 0.13 and 0.61 were measured for all soil types and at all concentrations. These coefficients indicate that methanol has a low adsorptive capacity on soils.

Reference 3

Endpoint:

adsorption / desorption: screening

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Type:

Koc

Value:

>= 0.13 - <= 0.61 L/kg

Reference 4

Endpoint:

adsorption / desorption: screening

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

Please refer to IUCLID section 13 for Read Across Justification.

Reason / purpose for cross-reference:

read-across source

Key result

Type:

log Koc

Value:

0.18 dimensionless

Reference 5

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

23.03.2007 - 28.03.2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Test temperature:

40°C +/- 0.5°C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus:
- Type: Agilent 100
- Type, material and dimension of analytical (guard) column: LiChrospher 100 CN 5 µm, L = 250 mm, ID = 4 mm
- Detection system: DAD at 210.4 nm


MOBILE PHASES
- Type: 20 % (v/v) acetonitrile / 80 % (v/v) water; flow rate 1 ml/min, isocratic
- pH: 7
- Solutes for dissolving test and reference substances: dissolved in the mobile phase

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column (thiourea)

REFERENCE SUBSTANCES
- Identity: as recommended in the guideline: thiourea (1.254 mg/ml), acetanilide (0.147 mg/ml), atrazine (0.0946 mg/ml), triadimenol (0.1092 mg/ml), monuron (0.1478 mg/ml), linuron (0.1076 mg/ml), pyrazophos (0.1208 mg/ml)


DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: concentration of test substance 3.9796 mg/ml, injection volume 5 µl
- Quantity of reference substances: injection volume 5 µl


REPETITIONS
- Number of determinations: 10 injections, each substance determined in duplicate


EVALUATION
- Calculation of capacity factors k': k' = (tR-t0)/t0
- Calculation of retention times: mean of 2 measurements
- Determination of the log Koc value: log k' values of the reference substances were plotted against their log Koc values as stated in the guideline. The Koc value of methyl acetate was determined by using this plot

Key result

Type:

log Koc

Value:

0.18 dimensionless

Details on results (HPLC method):

- Retention times of reference substances used for calibration: see table
- Details of fitted regression line (log k' vs. log Koc): equation of regression line: y = 1.7945x + 1.3607; R² = 0.9616
- Average retention data for test substance: Average retentione time 3.088

Transformation products:

not specified

Statistics:

not specified

Table 1: Mean retention times of the reference substances

Substance	Mean retention time [min]
Thiourea	2.533 (= dead time)
Acetanilide	4.498
Atrazine	7.624
Triadimenol	15.302
Monuron	7.351
Linuron	16.368
Pyrazophos	39.753

Validity criteria fulfilled:

not applicable

Remarks:

a reproducible method was used

Conclusions:

In a study according to OECD TG 121 and EU Method C.19 (HPLC Method) the Log Koc of the test item was determined to be 0.18.

Executive summary:

The adsorption coefficient of Methyl acetate was determined by HPLC method according to OECD TG 121 and EU Method C.19. The test substance as well as well as 7 reference substances were dissolved in a mixture of acetonitrile and water. Thiourea was used to define the dead time. Each substance was measured in duplicate and their capacitiy factors k' were calcuated. The log k' value were plotted against the respective log Koc values of the reference substances. The log Koc value of Methyl acetate was calculated by means of the regression line equation resulting in 0.18.

Description of key information

The study does not need to be conducted because the registration substance has a low octabol water partitioning coefficient and the adsorption potential of this substance is related to this parameter (study scientifically not necessary). However, based on a read across approach to Methyl acetate the Koc of the registration substance was determined to be 1.51 L/kg.

Key value for chemical safety assessment

Koc at 20 °C:

1.51

Additional information

The octanol water partitioning coefficient of the registration substance was determined to be Log Kow = 0.18 (please refer to IUCLID section 4.7). In accordance with column 2 of Annex VIII to Regulation (EC) No 1907/2006 (REACH) the study on adsorption/desorption screening does not need to be conducted if  "based on the physico-chemical properties the substance can be expected to have a low potential for adsorption (e.g. the substance has a low octanol water partition coefficient)". The very low octanol water partition coefficient of the registration substance indicates that the registration substance has a low potential for adsorption.

Nevertheless, supporting information for the read across source substances Methanol and Methyl acetate are available and summarized below.

Supporting information

Lokke (1984) studied the adsorption of methanol onto three different soil types at 6 °C. Adsorption coefficients of between 0.13 and 0.61 L/kg were measured for all soil types and at all concentrations. This results shows that Methanol has a low adsorptive capacity on soils.

The adsorption coefficient of Methyl acetate was determined by HPLC method according to OECD TG 121 and EU Method C.19 (Wieser, 2007). The capacity factors k' were calculated and plotted against the respective log Koc values of the reference substances. The Log Koc value of methyl acetate was calculated by means of the regression line equation resulting in 0.18 which corresponds to a Koc of 1.51 L/kg.

Conclusion

The study is considered scientifically not necessary because the registration substance has a low octanol water partitioning coefficient and was hence waived. Nevertheless, following a worst case approach, a Koc of 1.51 L/kg was derived based on supporting information for the read across source substance Methyl acetate.