2,4-Hexadienoic acid, 3-(trimethoxysilyl)propyl ester, (2E,4E)-

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

(Q)SAR

Adequacy of study:

key study

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

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 MBBPVPWIN 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

Temp.:

25 °C

Vapour pressure:

0.052 Pa

Conclusions:

A vapour pressure value of 5.2E-02 Pa at 25°C has been determined for the substance using an appropriate estimation method. The result is considered to be reliable.

Description of key information

Vapour pressure [3-(trimethoxysilyl)propyl-(2E,4E)-hexa-2,4-dienoate]: 5.2E-02 Pa at 25°C (QSAR)

Vapour pressure [3-(trihydroxysilyl)propyl-(2E,4E)-2,4-hexadienoate]: <1.0E-03 Pa at 25°C (QSAR)

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

Key value for chemical safety assessment

Vapour pressure:

0.052 Pa

at the temperature of:

25 °C

Additional information

A vapour pressure value of 5.2E-02 Pa 25°C was determined for the substance with the use of a validated QSAR estimation method. The result is considered to be reliable.

In contact with water, the substance hydrolyses rapidly to form 3-(trihydroxysilyl)propyl-(2E,4E)-2,4-hexadienoate and methanol.

The vapour pressure of 3-(trihydroxysilyl)propyl-(2E,4E)-2,4-hexadienoate was determined to be 8.0E-07 Pa at 25°C with the use of the same validated QSAR estimation method as the parent substance. However, since the descriptor range for the model is between 10^-3 to 10⁵ Pa, the result was reported as a lower limit of <1.0E-03 Pa.

 

Methanol has a reported vapour pressure of 12790 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.