Phenylacetylene

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data on water solubility of test item comes from an experimental study and is used in the experimental database of EPISuite. Even if the details on method are missing, this data is used as supporting data considering the EPISuite source as a model recommended by ECHA.

Qualifier:

equivalent or similar to guideline

Guideline:

other: Data on Water Solubility comes from a secondary source (EPISuite). No information on TEST GUIDELINE available.

Type of method:

other: Data on Water Solubility comes from a secondary source. No information on TYPE OF METHOD available.

Key result

Water solubility:

ca. 456 mg/L

Remarks on result:

other: temperature not reported

Conclusions:

The water solubility of test item was determined to be 456 mg/L.

Executive summary:

Data on logKow of test item comes from literature (Valvani,SC, C et Al., 1981).

Reference 2

Endpoint:

water solubility

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

December 2021

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:
The value is not an experimental result, however the QSAR model is recommended by the ECHA guidance document on information requirements, and is well documented with regard to validation parameters according to OECD principles. In addition, the substance investigated matches with the parameters of training set compounds and the result is considered fully reliable.

Reason / purpose for cross-reference:

reference to other study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

no guideline followed

Principles of method if other than guideline:

QSAR estimation

Specific details on test material used for the study:

Input: experimental Log Kow: 2.53

Key result

Water solubility:

ca. 796.2 mg/L

Temp.:

25 °C

Remarks on result:

other: Conc. based, loading rate, incubation duration and pH not provided

Estimation Accuracy

Training

The regression equations used by the WSKOWWIN program were trained with a dataset of 1450 compounds.

As noted in the methodology section, WSKOWWIN estimates water solubility with one of two possible equations.  When an experimental melting point is available, WSKOWWIN applies the equation containing both a melting point and the molecular weight (MW) parameters.  In the absence of a melting point, the equation containing just the molecular weight is used to make the estimate.  All compounds in the 1450 compound training set have known melting points or are known to be liquids at 25°C.  In this particular case, where the melting point of teh test item has not been used as input teh accurancy statistic is as follows:

r2: 0.934

std deviation: 0.585

avg deviation: 0.442

Validation

The WSKOWWIN estimation equations were initially validated on two datasets of compounds that were not included in the model training.  A relatively small dataset was tested that consisted of 85 compounds having experimental log Kow values, but no available melting points.  Many compounds in the 85 compound test set decompose before melting and would theoretically have very high melting points (e.g. amino acids and compounds having multiple nitrogens).  The accuracy statistics for the equation used by WSKOWWIN are:

number: 85

r2: 0.865

std deviation: 0.961

avg deviation: 0.714

A much larger dataset of 817 compounds was also tested.  All 817 compounds had experimental melting points, but none of the 817 compounds had a reliable experimental log Kow.  The log Kow values used for the validation-testing were estimated (primarily using the KOWWIN program available at that time); therefore, the water solubility estimates are based on estimates for log Kow.  Typically, estimates based on estimates reduce estimation accuracy, but this type of validation can provide insight into the ability of the method.  The accuracy statistics for this dataset are:

number: 817

r2: 0.902

std deviation: 0.615

avg deviation: 0.480

Estimation Domain

Appendix E of the Help section in EpiSuite gives the number compounds in the 1450 compound training set containing each of the correction factors.  The WSKOWWIN program applies an individual correction factor only once per structure [if at all] regardless of how many instances of the applicable structural feature occur in the structure.  The minimum number of instances is zero and the maximum is one.

 

Range of water solubilities in the Training set:

Minimum  =  4 x 10-7 mg/L (octachlorodibenzo-p-dioxin)

Maximum =  completely soluble (various)

 

Range of Molecular Weights in the Training set:

Minimum  =  27.03 (hydrocyanic acid)

Maximum =  627.62 (hexabromobiphenyl)

 

Range of Log Kow values in the Training set:

Minimum  =  -3.89 (aspartic acid)

Maximum =  8.27 (decachlorobiphenyl)

Currently there is no universally accepted definition of model domain.  However, users may wish to consider the possibility that water solubility estimates are less accurate for compounds outside the MW range, water solubility range and log Kow range of the training set compounds.  It is also possible that a compound may have a functional group(s) or other structural features not represented in the training set, and for which no correction factor was developed.  These points should be taken into consideration when interpreting model results.

Conclusions:

The calculated (QSAR) water solubility of test item is estimated to be 796.2 mg/L at 25°C (No melting point was used as input)

Executive summary:

The water solubility of the test substance was estimated using the recommended QSAR model WSKowWin v1.43. Even if the result shall be considered with restrictions considering the type of information (QSAR), the test item properties are within the application of domain of the model, so validation apply with acceptable restrictions.

The calculated water solubility is 796.2  mg/L at 25°C.

Description of key information

The calculated (QSAR) water solubility of test item is estimated to be 796.2 mg/L at 25°C (no melting point was used as input).

Key value for chemical safety assessment

Water solubility:

796.2 mg/L

at the temperature of:

25 °C

Additional information

Water Solubility of test items was reliably determined by a validated QSAR model using the experimental log Kow as input. No melting point was used. To support this data, an experimental study was available without detailed information on test method.  

This value is retained as key result.