Fast Pyrolysis Bio-oil

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Remarks:

EPI Suite v.4.11

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Justification for type of information:

1. SOFTWARE: U.S. Environmental Protection Agency for EPI Suite™ v.4.11 and the individual programs included within the software.
http://www.epa.gov/oppt/exposure/pubs/episuite.htm

2. MODEL: The WSKOWWIN program estimates the water solubility of an organic compound using the compounds log octanol-water partition coefficient (log Kow).

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
The study is based on eight representative components of the test material.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
The link: https://www.epa.gov/tsca-screening-tools/epi-suitetm-estimation-program-interface

EPI Suite (TM): Individual estimation programs and/or their underlying predictive methods and equations have been described in numerous journal articles in peer-reviewed technical journals. In addition, EPI Suite™ has undergone detailed review by a panel of EPA’s independent Science Advisory Board.

- Defined endpoint: water solubility

- Unambiguous algorithm: WSKOWWIN as part of EPI Suite is one of the most commonly used programs. The used equations and corrections are descibed in the attachment WSKOWWIN methodology. The estimation methodology used by WSKOWWIN (Meylan and Howard, 1994a,b) is described in the following document prepared for the U.S. Environmental Protection Agency (OPPT): Upgrade of PCGEMS Water Solubility Estimation Method (May 1994). A companion document (Validation of Water Solubility Estimation Methods Using Log Kow for Application in PCGEMS & EPI) also discusses the methodology. Also regression results are presented in the Attachment.

5. APPLICABILITY DOMAIN

The modelled representative compounds are organic substances covered by the applicability domain of WSKOWWIN.

Molecular weights of the representative components (test material) are within the minimum and maximum values in the Training Set for Molecular Weight (27.03 – 627.62) and for water solubilities (over 4 x 10-7 mg/L). The log Kow values are within the range of -3.89 - 8.27 except for b-sitosterol which logKow value exceeds the maximum being 9.65.

WSKOWWIN v1.4 includes an experimental water solubility database of 6230 compounds. Correlation is presented in the Attachment WSKOWWIN Accuracy and Domain.

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.

6. ADEQUACY OF THE RESULT

Accuracy of the calculated parameters versus experimental results of the representative compounds at 25 deg C are as follows, respectively:
Acetaldehyde: 2.568e+005 mg/L; 1e+006 mg/L,
Acetic acid: 4.759e+005 mg/L; 1e+006 mg/L,
b-Sitosterol: 4.632e-005 mg/L; -,
Furfural: 5.358e+004 mg/L; 7.41e+004 mg/L,
Glucose; 1e+006 mg/L; 1.2e+006 mg/L,
Methanol; 1e+006 mg/L; 1e+006 mg/L,
Naphthalene; 142.1 mg/L; 31 mg/L,
Phenol; 2.616e+004 mg/L; 8.28e+004 mg/L
(Attachment: WSKOWWIN Results).

Due to the nature of bio-oils, which as UVCB substance consists of more than 500 different compounds, it is technically irrelevant to test partition coefficient for the substance. Therefore, the computational method gives a reasonably reliable estimate on the weighted average of the parameter.

REFERENCES:

Meylan, W.M. and P.H. Howard. 1994a. Upgrade of PCGEMS Water Solubility Estimation Method (May 1994 Draft). prepared for Robert S. Boethling, U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington, DC; prepared by Syracuse Research Corporation, Environmental Science Center, Syracuse, NY 13210.

Meylan, W.M. and P.H. Howard. 1994b. Validation of Water Solubility Estimation Methods Using Log Kow for Application in PCGEMS & EPI (Sept 1994, Final Report). prepared for Robert S. Boethling, U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics, Washington, DC; prepared by Syracuse Research Corporation, Environmental Science Center, Syracuse, NY 13210.

Guideline:

other: REACH Guidance on QSARs R.6

Other quality assurance:

other: EPI Suite (TM): Individual estimation programs and/or their underlying predictive methods and equations have been described in numerous journal articles in peer-reviewed technical journals.

Type of method:

other: WSKOWWIN™: Estimates an octanol-water partition coefficient using the KOWWIN™ program, then estimates a chemical’s water solubility from this value and applicable correction factors if any.

Specific details on test material used for the study:

PHYSICAL-CHEMICAL PROPERTIES MODELLED WITH EPIWIN
v.4.11

Compound CAS number

Acetic acid CAS no 64-19-7;
Methanol CAS no 67-56-1;
Phenol CAS no 108-95-2;
Acetaldehyde CAS no 75-07-0;
Furfural CAS no 98-01-1;
Glucose CAS no 50-99-7;
Naphthalene CAS no 91-20-3;
Beta-sitosterol CAS no 83-46-5.

Test material, UVCB substance, consists of more than 500 different compounds such as long-chain fatty acids, PAHs, sesquiterpenes (Jenner et al., 2011), and phytosterols (Hewitt et al., 2000).
According to analytical data, such compounds may form ca. 4 % of FPBO in total.

REFERENCES
Hewitt, L.M., Parrot, J.L., Weells, K.L., Calp, M.K., Biddiscombe, S., McMaster, M.E., Munkittrick, K.R., van der Kraak, G., 2000. Characteristics of ligands for the Ah receptor and sex steroid receptors in hepatic tissues of fish exposed to bleached kraft mill effluent. Environ Sci Technol 34:4327-4334.

Water solubility:

562 000 mg/L

Conc. based on:

other: Modelled with EPIWIN

Temp.:

25 °C

Remarks on result:

other: EPI Suite v.4.11, WSKOWWIN, weighted average 5.62E+05 mg/l, average 3.52E+05 mg/l (8 components)

Details on results:

See Table 1 (section_ "any other information on results incl. tables")

TABLE 1. Water solubility

PHYSICAL-CHEMICAL PROPERTIES MODELLED WITH EPIWIN
v.4.11
	Compound	FPBO, ww-%	MW (g/mol)	WS (mg/l)
	acetic acid	2.9	60.05	4.76E+05
	methanol	0.41	32.04	1.00E+06
	phenol	0.42	94.11	2.62E+04
	acetaldehyde	0.05	44.05	2.57E+05
	furfural	0.15	96.09	5.36E+04
	glucose	0.96	180.16	1.00E+06
	naphthalene	0.00079	128.18	142.1
	beta sitosterol	0.057	414.72	4.63E-05
Weighted average			88.95	5.62E+05
Average			131.175	3.52E+05

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

Molecular weight, MW

Water solubility WS (WSKOWWIN) at 25 deg C

Conclusions:

Water solubility values (mg/l) of individual eight compounds range from 4.63E-05 to 1.00E+06 with the weighted average being 5.62E+05 mg/l.

Executive summary:

Water solubility values (mg/l) of the main components (contributing 5 % of the total wet weight) were determined using WSKOWWIN program developed by U.S. Environmental Protection Agency. Water solubility values of the individual components range from 4.63E-05 to 1.00E+06 with the weighted average being 5.62E+05 mg/l.

Description of key information

Water solubility of FPBO has not been tested due to UVCB nature of the substance. Water solubility values (mg/l) of the main components (contributing 5 % of the total wet weight) were determined using WSKOWWIN program developed by U.S. Environmental Protection Agency. Water solubility values of the individual components range from 4.63E-05 to 1.00E+06 with the weighted average being 5.62E+05 mg/l.

Key value for chemical safety assessment

Water solubility:

562 000 mg/L

at the temperature of:

25 °C

Additional information

Pyrolysis liquids can be considered as solutions of water and watersoluble organic compounds with water-insoluble, mostly oligomeric, material. The ratio of these fractions depends on the feedstock, the pyrolysis process, production and storage conditions. The water-insoluble fraction, mainly lignin-derived oligomers, usually accounts for about 20–25 wt-% of the liquid (wet basis), while the water concentration typically ranges from 20 to 30 wt-%. The water-soluble fraction consists mainly of water, “sugars” (sugartype compounds, ether-insolubles), acids, aldehydes, ketones, pyrans and furans (Oasmaa & Peacocke 2010).

References:

Anja Oasmaa & Cordner Peacocke. Properties and fuel use of biomass-derived fast pyrolysis liquids.

A guide. Espoo 2010. VTT Publications 731. 79 p. + app. 46 p.