Phenol, mono- + distyrenated (MSP+DSP)

Henry's Law constant

Link to relevant study record(s)

Reference

Endpoint:

Henry's law constant

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other:

Remarks:

Accepted, well-documented calculation method. Result is related to phenol, styrenated as measured values of vapour pressure and water solubility for the technical product of phenol, styrenated were used in the calculation of HLC. Molecular weight was derived as mean from the molecular weigths of the components and the quantitative composition in the technical product.

Justification for type of information:

1. SOFTWARE
US EPA (2012). Estimation Programs Interface Suite™ (EPI Suite) for Microsoft® Windows, v 4.11. United States Environmental Protection Agency, Washington, DC, USA

2. MODEL (incl. version number)
Model HENRYWIN, version 3.20

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
Not applicable (multi-constituent substance)

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: yes, HLC
- Unambiguous algorithm: yes (VP / WSol x MW)
- Mechanistic interpretation: input parameters are indicative for the distribution of a substance in air and in water.

5. APPLICABILITY DOMAIN
- Descriptor domain: not applicable
- Structural and mechanistic domains: not applicable
- Similarity with analogues in the training set: not applicable

6. ADEQUACY OF THE RESULT
Calculation result is based on measured data of the substance phenol, styrenated. It is considered to characterise satisfactorily the partitioning of the substance between air and water.

Principles of method if other than guideline:

- Software tool(s) used including version: US EPA (2012). Estimation Programs Interface Suite™ (EPI Suite) for Microsoft® Windows, v 4.11. United States Environmental Protection Agency, Washington, DC, USA.
- Model(s) used: Model HENRYWIN, version 3.20
- Model description: HENRYWIN estimates Henry's Law Constant (HLC) by two separate methods that yield two separate estimates. The first method is the Bond Contribution Method and the second is the Group Contribution Method. For both methods, the chemical structure of the substance has to be know (i.e. SMILES notation). The Bond Method is able to estimate many more types of structures than the Group Method, because it has a more extensive library of bond contribution values.
In addition, HLC can be calculated with a simple method based on phys.-chem. data of a substance using the equation VP / WSol x MW. As phenol, styrenated is a multi-constituent substance, this method was used to estimate HLC applying measured values of VP and WSol and an average molecular weight.
- Justification of QSAR prediction: Estimates of HLC are widely used and are considered to be sufficiently accurate. The equation presented above correlates parameters indicative for the concentration distribution of a substance in air and in water.

Key result

H:

0.036 Pa m³/mol

Temp.:

20 °C

Remarks on result:

other: HLC was calculated by the equation HLC = VP / WSol * MW using the data determined for phenol, styrenated (LS 500)

HLC can be calculated using genuine data of a substance (vapour pressure / water solubility x molecular weight). For phenol, styrenated the values 0.0049 Pa , 31.8 mg/L, and 233 g/mol were used. Physical chemical data have been measured with phenol, styrenated (see Section 4) and a molecular weight was determined based on the moledular weigth and the percentage of the different constituents (mono and distyrenated phenols) of phenol, styrenated.

HLC = VP / WSol x MW = 0.0049 Pa / 31.8 mg/L x 236

HLC = 0.0364 Pa m³/mol

Description of key information

Henry's Law Constant was determined using an accepted calculation method (US EPA EPI Suite). Calculation is based on the measured values for vapour pressure and water solubility and on an average molecular weight of the technical product phenol, mono- & distyrenated

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):

0.036

at the temperature of:

20 °C

Additional information

Henry's Law constant was calculated using the program HENRYWIN v3.20 included in US EPA EPI Suite v4.11. Calculation is based on measured values of vapour pressure and water solubility and on an average molecular weight of the technical product phenol, mono- & distyrenated thus representing this substance. Using these parameters, a HLC value of 0.0364 was calculated.

For a major constituent (2-(1-phenylethyl)phenol, approx. 60 %) of phenol, mono- & distyrenated, HLC was estimated with two different methods built into the program HENRYWIN v3.20. The bond estimation method resulted in a HLC estimate of 0.00672 Pa m³/mol, while the calculation using vapour pressure, water solubility (input data were estimates from EPI Suite calculations), and the molecular weight of the substance yielded in a value of 0.01039 Pa m³/mol. Both values are fairly consistent being different only by a factor of ca. 1.5.