N-(3-(trimethoxysilyl)propyl)ethylenediamine

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Principles of method if other than guideline:

The Halm-Stiel and Antoine equations were used to extrapolate vapour pressure at 20°C from vapour pressures measured at elevated temperatures.

GLP compliance:

not specified

Type of method:

other: Extrapolation method

Key result

Test no.:

#1

Temp.:

20 °C

Vapour pressure:

0.4 Pa

Remarks on result:

other: Based on Halm-Stiel equation

Key result

Test no.:

#2

Temp.:

20 °C

Vapour pressure:

0.3 Pa

Remarks on result:

other: Based on the Antoine equation

Table 1: Measured vapour pressure and temperature data

T °C	P(mm Hg)	P (Pa)
121.0	5	667
137.0	10	1333
145.7	15	2000
159.2	25	3333
162.8	30	3999
170.9	40	5332
175.6	50	6665
180.6	60	7998
186.6	70	9331
190.9	80	10664
193.9	90	11997

The Halm-Stiel and Antoine equations were used to extrapolate vapour pressure at 20°C from vapour pressures measured at elevated temperatures ranging from 121-194°C.

 

The extrapolated vapour pressure of the test substance at 20°C was 0.4 Pa and 0.3 Pa, based on the Halm-Stiel equation (Smith 1986) and the Antoine equation (Flaningam and Smith 1994) respectively.

Conclusions:

A vapour pressure of 0.3 and 0.4 Pa at 20°C has been determined for the test substance using a relevant estimation method based on the Antoine equation (Flaningam and Smith 1994) and Halm-Stiel equation (Smith 1986), respectively. These results are considered reliable.

Reference 2

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

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:

See attached QMRF/QPRF

Principles of method if other than guideline:

The result was obtained using an appropriate QSAR method (see attached QMRF and QPRF for details).

The model is an adaptation of the existing SRC model MPBPVPWIN v 1.43, which is a component of the EPI Suite. This existing model uses the normal boiling point as input. Whilst this method is good in principle, the model was developed using a wide range of organic chemicals and only a few organosilicon compounds. Therefore, a validation procedure was undertaken to assess the applicability of the model to organosilicon compounds. It was noted that the MPBPVPWIN model gave a systematic error; therefore, the current model was developed to correct this. The current model is a linear regression based QSAR, with the vapour pressure prediction from MPBPVPWIN as the descriptor. The adapted model applies to organosilicon substances.

Key result

Test no.:

#1

Temp.:

25 °C

Vapour pressure:

0.42 Pa

Conclusions:

A vapour pressure value of 0.42 Pa at 25°C has been determined for the substance using an appropriate estimation method. The result is considered reliable.

Description of key information

Vapour pressure [N-(3-(trimethoxysilyl)propyl)ethylenediamine: 0.4 Pa at 20°C (WOE)

 

Vapour pressure [N-(3-(trihydroxysilyl)propyl)ethylenediamine:  6.8E-06 Pa at 20°C (QSAR)

 

Vapour pressure [methanol]: 12790 Pa at 20°C

Key value for chemical safety assessment

Vapour pressure:

0.4 Pa

at the temperature of:

20 °C

Additional information

There are two reliable vapour pressure values for the substance. Vapour pressures of 0.3 and 0.4 Pa at 20°C were obtained for the substance by extrapolation from higher temperature using the Antoine equation and Halm-Stiel equation, respectively, using the same data set (SEHSC 2003). Additionally, a predicted vapour pressure of 0.42 Pa at 25°C was determined for the substance using a validated QSAR estimation method. All results are considered to be reliable and add weight of evidence that the substance has a low vapour pressure. The vapour pressure value of 0.4 Pa at 20°C is averaged from the reliable results.

 

In other available secondary sources to which no reliability could be assigned, a vapour pressure limit of < 133 Pa and a value of 150 Pa at 20°C were reported for the substance.

 

Differences in vapour pressure determination could be as a result of differences in the purity of the commercial samples tested and the test method used.

 

In contact with water, the submission substance hydrolyses very rapidly to form N-(3-(trihydroxysilyl)propyl)ethylenediamine and methanol.

 

The vapour pressure of the silanol hydrolysis product was determined to be 6.8E-06 Pa at 25°C using the same validated QSAR estimation method as the parent submission substance.

 

Methanol has a reported vapour pressure of 12 790 Pa at 20°C (OECD 2004)

 

Reference:

 

OECD (2004): SIDS Initial Assessment Report for SIAM 19, Berlin, Germany, 18-20 October 2004, Methanol, CAS 67-56-1.