Reaction mass of [3-(trimethoxysilyl) propyl]urea, [3-(dimethoxyethoxysilyl) propyl]urea, [3-(methoxydiethoxysilyl) propyl]urea and [3-(triethoxysilyl) propyl]urea.

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 May 1999 - 02 Jun 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

GLP compliance:

yes

Type of method:

static method

Temp.:

20 °C

Vapour pressure:

30.3 Pa

Remarks on result:

other: ± 1.5 Pa

Details:

The Static Technique was used for the determination of the vapour pressure at 20°C.

 

For each temperature, a selected number of measurements were used for the calculations. The results of the calculations are summarized in Table 1.

 

Table 1: Determination of the vapour pressure of the test substance at 3 different temperatures, using the Static Technique 

Measurement^1	Temperature (°C)	Mean vapour pressure + 2σn-1
		ln (p)	Pa
3 – 18	37.09	3.98 + 0.03	53.5 + 1.6
22 – 32	30.30	3.74 + 0.06	41.9 + 2.4
34 - 48	24.09	3.56 + 0.02	35.2 + 1.7

 

¹A selected number of measurements were used in the calculations.

 Note: the calculations were performed using un-rounded values.

 

The resulting values given in the table were plotted against the reciprocal temperature (T^-1) in Kelvin, taking into account the calculated error.

 

Fitting these data using the least squares method gives a value of 30.3 Pa with 1.5 Pa for 2σ_n-1(ie. 5%) for the vapour pressure of the test substance at 20°C. The maximum deviation between the fit and the data points is always less than about 2%. Errors made in estimating the mean value per temperature series are up to 5.8%. So a value of 2 Pa (ie. 6.6%) is a reasonable value for the uncertainty in the final result.

Conclusions:

A vapour pressure value of 30.3 ± 1.5 Pa at 20°C was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.

Description of key information

Ureidopropyltrialkoxysilane, mixed methoxy and ethoxy esters: 30.3 ± 1.5 Pa at 20°C (measured)

Key value for chemical safety assessment

Vapour pressure:

30.3 Pa

at the temperature of:

20 °C

Additional information

A vapour pressure of 30.3 ± 1.5 Pa at 20°C was determined for the substance by the static method according to OECD Guideline 104.