Triethoxy(3-thiocyanatopropyl)silane

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Version / remarks:

Council Regulation (EC) No 440/2008 of 30 May 2008

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

adopted on 27 July 1995

GLP compliance:

no

Type of method:

static method

Key result

Test no.:

#1

Temp.:

20 °C

Vapour pressure:

< 100 Pa

Key result

Test no.:

#2

Temp.:

20 °C

Vapour pressure:

ca. 0.23 Pa

Remarks on result:

other: calculated by the reviewer using the Antoine equation

Key result

Test no.:

#3

Temp.:

25 °C

Vapour pressure:

ca. 0.38 Pa

Remarks on result:

other: calculated by the reviewer using the Antoine equation

	Temperature [°C]	Vapour pressure [hPa]
	136.7	7.8
	156.8	20
	166.3	29.8
	178.2	49.5
	199.7	105.1
	228.3	260.6
	270.2	1005.1
	249.1	756.7
	233.4	500
Calculated pressure	20	< 1

 

 

An Antoine equation was fitted to the measured data points by regression analysis minimizing the sum of squares of relative pressure deviation.

 

Antoine equation:	ln p = A – B / (T - C)	[p in kPa; T in K]
A = 17.4547	B = 6537.70	C = 40.00

 

The vapour pressure of the test item at 20 °C was extrapolated from the Antoine equation. It was determined to < 1 hPa (at 20 °C).

 

The reviewers of this study calculated the vapour pressure as 0.23 Pa at 20°C and 0.38 Pa at 25°C, using the Antoine equation.

Conclusions:

A vapour pressure of < 1 hPa at 20°C was determined using an appropriate guideline method not according to GLP. The result is considered reliable.

Description of key information

Vapour pressure [triethoxy(3-thiocyanatopropyl)silane]: < 100 Pa at 20°C (OECD 104)

Vapour pressure [(3-thiocyanatopropyl)silanetriol]: 2.0E-06 Pa at 25°C (QSAR)

Vapour pressure [ethanol]: 7910 Pa at 25°C

Key value for chemical safety assessment

Vapour pressure:

0.38 Pa

at the temperature of:

25 °C

Additional information

A vapour pressure limit of < 1 hPa was extrapolated from measurements between 136-270°C using a static method according to OECD Test Guideline 104. An Antoine equation was fitted to the measured results and a vapour pressure at 20 and 25°C was calculated by the study reviewer as 0.23 and 0.38 Pa, respectively. The results are considered reliable and selected as key.

 

The key value is supported by a predicted vapour pressure of 0.31 Pa at 25°C, determined for the registered substance using a validated QSAR estimation method; the result is considered to be reliable. The QSAR value has been validated using reliable measurements for structural analogues reflecting the main constituent in the registered substance.

 

In the other available secondary source to which no reliability could be assigned, a vapour pressure of < 1 hPa at 20°C was reported for the substance.

 

Triethoxy(3-thiocyanatopropyl)silane (CAS 34708-08-2; EC No. 252-161-3) hydrolyses moderately in contact with water to form (3-thiocyanatopropyl)silanetriol and ethanol (CAS 64-17-5; EC No. 200-578-6).

 

The vapour pressure of the silanol hydrolysis product, (3-thiocyanatopropyl)silanetriol was determined to be 2.0E-06 Pa at 25°C using an accepted QSAR estimation method. The result is considered reliable and indicative of a low vapour pressure.

 

Ethanol has a reported vapour pressure of 7910 Pa at 25°C (Daubert, T E and Danner R P (1985))

 

Reference:

 

Daubert, T E and Danner R P (1985).Physical and Thermodynamic properties of Pure Chemicals. Data Compilation)