Tetramethylammonium hydroxide

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

18 September 2012 - 17 December 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Version / remarks:

(2009)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

(2006)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7950 (Vapor Pressure)

Version / remarks:

(1996)

Deviations:

no

GLP compliance:

yes

Type of method:

effusion method: isothermal thermogravimetry

Remarks on result:

not determinable

The weight loss observed with Program 1 (from 30 to 60°C) was due to evaporation of water. The weight loss observed with Program 2 (from 70 to 140°C) was due to reaction/decomposition of the test sample (observed as non-linear weight loss) and evaporation of the degradation products formed (i.e. methanol and trimethylamine). Weight loss curves: see attachment.

Conclusions:

Using the isothermal thermogravimetric effusion method (EC A.4, OECD 104 and EPA OPPTS 830.7950), no vapour pressure could be determined for the tested substance. During heating, evaporation of water was observed followed by reaction/decomposition and subsequent evaporation of the degradation products.

Reference 2

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

February 2013

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:

The QSAR model MPBPWIN v1.43 from EPISuite v4.10 was used in order to predict the vapour pressure. This model is a known calculation tool for screening this end point.

Qualifier:

according to guideline

Guideline:

other: Guidance on information requirements and chemical safety assessment Chapter R.6: QSARs and grouping of chemicals,REACH guidance on QSAR R.6, May 2008

Principles of method if other than guideline:

EIP Suite program-MPBPWIN v 1.43 for predicting melting point, boiling point and vapour pressure. The vapour pressure is estimated by three methods:
• the Antoine method (Lyman et al 1990)
• the modified Grain method (Lyman 1985)
• the Mackay method (Lyman 1985).
All three methods use the normal boiling point to estimate the vapour pressure.

The computer estimations made by MPBPVP report all three methods and a “suggested” value. For solids, the suggested vapour pressure is the modified Grain estimate. The modified Grain method is a modification of the modified Watson method. It is probably the best all round VP estimation currently available (Meylan and Howard 1994) and is used by USEPA in the PC-CHEM program.

The validity and applicability criteria, as described in the REACH guidance, of the QSAR estimation have not been evaluated in detail. However, the QSAR model is a well-known, widely used and commonly accepted screening tool.

GLP compliance:

no

Type of method:

other: calculation

Key result

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

other: MPBPWIN v1.43-Modified Grain method prediction.

More information on the (Q)SAR model applied: see attached document " Vapor pressure_EPIWIN_background"

Conclusions:

Using EPI Suite MPBPWIN v1.43, the vapour pressure of tetramethylammonium hydroxide was calculated to be 1.54x10^-4 Pa (modified Grain method).

Reference 3

Endpoint:

vapour pressure

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

supporting study

Study period:

2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data taken from OECD SIDS of Tetramethylammonium hydroxide (CAS no.: 75-59-2). Review Process Prior to the SIAM: Japanese government peer-reviewed the documents, audited selected studies. Quality check process: Japanese government peer-review committee performed spot checks on randomly selected endpoints and compared original studies with data in the SIDS dossier. Reliability in the SIDS: 2 (reliable estimation method).

GLP compliance:

no

Key result

Temp.:

25 °C

Vapour pressure:

0 hPa

Remarks on result:

other: Calculated using MPBPWIN v1.41 (2005); 1.55x10^-4 Pa

Reference as mentioned in the SIDS:

CERI (2005a) Chemicals Evaluation and Research Institute (CERI), Japan.MPBPWIN v1.41 calculation, unpublished data.

Conclusions:

Using EPI Suite MPBPWIN v1.41, the vapour pressure of tetramethylammonium hydroxide was calculated to be 1.55E-04 Pa (data taken form OECD SIDS Initial Assessment report for SIAM 22).

Description of key information

The isothermal thermogravimetric effusion method (EC A.4, OECD 104) did not result in a value for the vapour pressure due to thermal decomposition.  Using EPI Suite MPBPWIN v1.43, the vapour pressure of tetramethylammonium hydroxide was predicted to be 1.54E-04 Pa (modified Grain method). 

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C

Additional information

Weight of evidence approach:

- During the performance of the isothermal thermogravimetric effusion method no vapour pressure could be determined for tetramethylammonium hydroxide pentahydrate. During heating, evaporation of water was observed followed by reaction/decomposition and subsequent evaporation of the degradation products.

- Using EPI Suite MPBPWIN v1.43, the vapour pressure of tetramethylammonium hydroxide was predicted to be 1.54x10^-4 Pa (modified Grain method).

- Using EPI Suite MPBPWIN v1.41, the vapour pressure of tetramethylammonium hydroxide was predicted to be 1.55x10^-4 Pa (data taken from OECD SIDS Initial Assessment report for SIAM 22).

- EPI Suite MPBPWIN is a known calculation tool for screening this end point.

 

Calculation with MPBPWIN v1.43 resulted in a low vapour pressure as was expected for a solid salt like tetramethylammonium hydroxide.The value given in the OECD SIDS (peer-reviewed) confirmed this low value. The value calculated with the most recent program, MPBPWIN v1.43, was reported as key value.