3-(dimethylamino)propylurea

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

22 Februar - 18 August 2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD 113 Screening Test for Thermal Stability and Stability in Air

Version / remarks:

1981

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

2006

GLP compliance:

yes (incl. QA statement)

Type of method:

dynamic method

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Manufacturer, UA21412002
- Purity, including information on contaminants, isomers, etc.: Content: 75% 3-(N,N-Dimethyl)propyl-urea and 25% Polyethylenglycol

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store container tightly closed at a well-ventilated place. Store in the original container. Do not store with acids.

The vapour pressure was started to measure in the temperature range of 132.0 °C to 167.1 °C. At approx. 140 °C it was observed that a white solid deposits within the glass tubes of the apparatus . This indicates a chemical change during the measurement. Therefore, the system is not in an equilibrium state any more, which is the basic prerequisite of the determination method. The measurement was aborted.

The three data points, which were recorded until abort, are summarised in Table 2. However, as the test item changed its composition or chemical identity, the recorded data values may not be correct.

 

Table 2:     Recorded data points of the dynamic method until abort.

Measurement No.	Temperature / °C	Vapour pressure / hPa	Remark
1	132.0	(25.2)	measured up
2	139.7	(34.8)	measured up
3	167.1	(48.7)	measured up

The vapour pressure of the test item  could not be determined by using the Vapour-Liquid Equilibrium method, according to Regulation (EC) No 440/2008 Method A.4. Vapour Pressure and OECD Test Guideline 104 (2006), because the test items composition or chemical identity changed during the measurement at approx. 140 °C.

Therefore, no dynamic equilibrium could be established during the test and no statement can be made regarding the vapor pressures at 20, 25 or 50 °C.

 

Conclusions:

The vapour pressure of the test item PU-2021-971 could not be determined by using the Vapour-Liquid Equilibrium method, .according to Regulation (EC) No 440/2008 Method A.4. Vapour Pressure and OECD Test Guideline 104 (2006), because the test items composition or chemical identity changed during the measurement at approx. 140 °C.
Therefore, no dynamic equilibrium could be established during the test and no statement can be made regarding the vapor pressures at 20, 25 or 50 °C.

Reference 2

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

1 Febraury 2023

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 limited documentation / justification

Justification for type of information:

1. SOFTWARE EPI models (via Danish QSAR database) and OECD Toolbox
2. Version: 4.11 Update 2017;

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


4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
[[Explain how the model fulfils the OECD principles for (Q)SAR model validation. Consider attaching the QMRF and/or QPRF or providing a link]
- Defined endpoint: vapour pressure
- Unambiguous algorithm:
- Defined domain of applicability: not reported
-------+-----+--------------------------------------------+---------+--------
TYPE | NUM | LOGKOW FRAGMENT DESCRIPTION | COEFF | VALUE
-------+-----+--------------------------------------------+---------+--------
Frag | 2 | -CH3 [aliphatic carbon] | 0.5473 | 1.0946
Frag | 3 | -CH2- [aliphatic carbon] | 0.4911 | 1.4733
Frag | 1 | -NH2 [aliphatic attach] |-1.4148 | -1.4148
Frag | 1 | -NH- [aliphatic attach] |-1.4962 | -1.4962
Frag | 1 | -N< [aliphatic attach] |-1.8323 | -1.8323
Frag | 1 | -NC(=O)N- [urea] | 1.0453 | 1.0453
Const | | Equation Constant | | 0.2290
-------+-----+--------------------------------------------+---------+--------
Log Kow = -0.9011

- Appropriate measures of goodness-of-fit and robustness and predictivity:
- Mechanistic interpretation:

5. APPLICABILITY DOMAIN
[Explain how the substance falls within the applicability domain of the model]
- Boiling Point: 270.21 deg C (Adapted Stein and Brown Method)

Melting Point: 151.79 deg C (Adapted Joback Method)
Melting Point: 44.11 deg C (Gold and Ogle Method)
Mean Melt Pt : 97.95 deg C (Joback; Gold,Ogle Methods)
Selected MP: 71.03 deg C (Weighted Value)

Principles of method if other than guideline:

- Software tool(s) used including version: 4.11 Update 2017
- Model(s) used: MPBPWIN v1.44
- Model description: see field 'Justification for non-standard information', 'Attached justification' and/or 'Cross-reference'
- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' and/or 'Cross-reference'

GLP compliance:

no

Type of method:

other: Modified Grain Method

Key result

Test no.:

#1

Temp.:

25 °C

Vapour pressure:

0.459 Pa

Vapor Pressure Estimations (25 deg C):

  (Using BP: 270.21 deg C (estimated))

  (Using MP: 71.03 deg C (estimated))

    VP:  0.00328 mm Hg (Antoine Method)

      :  0.437 Pa  (Antoine Method)

    VP:  0.00344 mm Hg (Modified Grain Method)

      :  0.459 Pa  (Modified Grain Method)

    VP:  0.00595 mm Hg (Mackay Method)

      :  0.794 Pa  (Mackay Method)

  Selected VP:  0.00344 mm Hg (Modified Grain Method)

             :  0.459 Pa (Modified Grain Method)

  Subcooled liquid VP:  0.00935 mm Hg (25 deg C, Mod-Grain method)

                     :  1.25 Pa  (25 deg C, Mod-Grain method)

Key value for chemical safety assessment

Vapour pressure:

0.45 Pa

at the temperature of:

20 °C