Choline hydroxide

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

calculation (if not (Q)SAR)

Remarks:

Estimated by calculation

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientifically accepted calculation method

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: REACH guidance on QSAR R.6, May 2008

Deviations:

not applicable

Principles of method if other than guideline:

MPBPWIN program (v 1.43): scientifically accepted calculation method for organic chemicals

GLP compliance:

no

Remarks:

not applicable

Type of method:

other: estimated by calculation

Key result

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

other: Modified Grain Method (MPBPWIN v1.43), calculated for pure choline hydroxide

Temp.:

25 °C

Vapour pressure:

2 828.4 Pa

Remarks on result:

other: Modified Grain Method (MPBPWIN v1.43), calculated for 45 % aqueous solution of choline hydroxide

Results

 

Running Choline Hydroxide (CAS: 123-41-1) through the EPISUITEMPBPWINtool gave the following:

 

Predicted BP = 415.48 °C (Adapted Stein and Brown method)

Predicted MP = 160.24 °C (Weighted method derived from 285.48 for Adapted Joback method and 128.93 for Gold and Ogle method)

Predicted VP = 1.43x10^-7 Pa at 25 °C (Modified Grain method using the predicted BP and MP).

 

The EPISUITEMPBPWINdata file is given in Figure 1.

 

As the Choline base is a 45 % solution of Choline Hydroxide in water, the individual vapour pressure values for each of the components was used to estimate the vapour pressure of the mixture by multiplying the predicted value by the mole fraction for each of the components and then summing together, with a vapour pressure value used for water of 3172.5 Pa at 25 °C.

 

moles choline hydroxide = 45/121.18 = 0.3713

moles water = 55/18.02 = 3.0522

 

total moles = 3.4235

 

mole fraction choline hydroxide = 0.3713/3.4235 = 0.1085

mole fraction water = 3.0522/3.4235 = 0.8915

 

VPmix = 0.1085*1.43x10^-7+ 0.8915*3172.5 = 2828.4 Pa at 25 °C.

Conclusions:

The vapour pressure of the pure choline hydroxide was calculated to be 1.43 * E-7 Pa at 25 °C using the Modified Grain method of MPBPWIN program v1.43. For the calculation an estimated boiling point of 415.48 °C (Adapted Stein and Brown method) was used.
As the substance is marketed as an 45 % aqueous solution, the vapour pressure was calculated using Raoult´s law and an experimental vapor pressure value for water of 3172.5 Pa at 25 °C, resulting in a calculated vapour pressure of 2828.4 Pa at 25 °C which is in the scientifically expected range as it is close to the vapour pressure of water.

Executive summary:

Intertek estimated the Vapour presure (as well as melting and boiling point) of Choline hydroxide in 2013 (Intertek, 2013) using MPBPWIN program (v 1.43) made available by the U.S. Environmental Protection Agency. This program requires just the input of the chemical structure of the desired compound by SMILES notation. The calculation is done by three different methods: Antoine, Modified Grain and Mackay, whereby the Modified Grain method is preferentially utilized. By taking this method into account and using an estimated boiling point of 415.48 °C, pure choline hydroxide has a vapour pressure of 1.43 * E-7 Pa at 25 °C.

Using Raoult´s law and an experimental vapor pressure value for water of 3172.5 Pa at 25 °C, the vapour pressure of a 45 % solution of choline hydroxide can be calculated to 2828.4 Pa at 25 °C. The result was gained by a scientifically accepted calculation method.

Reference 2

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

14 JUN 2022

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:

1. SOFTWARE
OECD QSAR toolbox v4.5

2. MODEL (incl. version number)
MPBPWIN v1.44

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
OCCN(O)(C)(C)C

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Please refer to the QMRF attached under 'Attached justification'.

5. APPLICABILITY DOMAIN
Please refer to the QPRF attached under 'Attached justification'.

Guideline:

other: REACH guidance on QSAR R.6

Version / remarks:

May 2008

Principles of method if other than guideline:

Software tool(s) used including version: OECD QSAR toolbox v4.5, EPI Suite v4.11
- Model(s) used: MPBMWIN v1.44
- Model description: see field 'Attached justification'
- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification'

Specific details on test material used for the study:

OCCN(O)(C)(C)C

Key result

Temp.:

25 °C

Vapour pressure:

0 Pa

Remarks on result:

other: Modified Grain Method

Temp.:

25 °C

Vapour pressure:

0 mm Hg

Remarks on result:

other: Modified Grain Method

Conclusions:

This new calculation was conducted in order to evaluate if the newer available Version of the QSAR model (MPBPWIN v1.44) would calculate the same results as already reported in the study Intertek, 2013. Indeed, the vapour pressure of test item was calculated again to be 1.43 * E-7 Pa at 25 °C using the Modified Grain method of MPBPWIN program v1.44.

Executive summary:

This new calculation was conducted in order to evaluate if the newer available Version of the QSAR model (MPBPWIN v1.44) would calculate the same results as already reported in the study Intertek, 2013. Indeed, the vapour pressure of test item was calculated again to be 1.43 * E-7 Pa at 25 °C using the Modified Grain method of MPBPWIN program v1.44.

 

 

Description of key information

Vapour pressure:
1.43 * E-7 Pa at 25 °C (Modified Grain Method (MPBPWIN v1.44 and v1.43), calculated for pure Choline hydroxide by Intertek, 2013, and Chemservice 2022)
2828.4 Pa at 25°C (Modified Grain Method (MPBPWIN v1.43), calculated for 45 % aqueous solution of choline hydroxide via Raoult´s law by Intertek, 2013)

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

25 °C

Additional information

The vapour pressure of test item was calculated to be 1.43 * E-7 Pa at 25 °C using the Modified Grain method of MPBPWIN program v1.43 (by Intertek, 2013) and v1.44 (by Chemservice, 2022). 

The newer available version of the QSAR model (MPBPWIN v1.44) provides the same results as already reported in the study Intertek, 2013.