Bis(1-n-butyl-3-methylcyclopentadienyl)zirconium dichloride

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7950 (Vapor Pressure)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

Principles of method if other than guideline:

Test Procedure
The entire system was initially evacuated to achieve acceptable vacuum pressure at the target operating temperatures used for the study (20° and 30°C ± 1°C). The background deceleration rate (DCR) of the ball was monitored for six hours to establish an offset value (background correction) for subsequent measurements with reference or test substance present. The parameters of the spinning rotor gauge were set to record a deceleration measurement every 30 seconds. Once obtained, the offset value (expressed as mean deceleration rate) was entered into the spinning rotor gauge controller. This value was then converted to an offset pressure according to molecular weight and this value is subtracted from each measurement therefore vapor pressure is the net difference. Typical experimental parameters for SRG measurements are summarized in Table 1.

Prior to the analyses of the reference and test substance at each temperature, a background vapor pressure, measured as a slow linear increase in pressure due to out-gassing and permeation, was determined a minimum of three times using the appropriate molecular weight and temperature parameter. The sample chamber was evacuated to achieve a steady-state pressure. The mean and standard deviation of the steady state pressure were used as an indication of equilibration. After the system was pumped to a relatively stable pressure, the background pressure was recorded. Then the isolation valve between the vacuum pumps and the sensor head was closed and the pressure increase was monitored until a slow linear pressure increase was recorded.

Approximately one-gram samples of benzoic acid were used as a vapor pressure reference to verify the accuracy of the system configuration prior to the analysis of the test substance at each temperature. The pressure increase of the reference substance was monitored by the SRG at 10 second intervals. The vapor pressure of the reference substance by the SRG method was compared to the published values by the gas saturation method and by the vapor pressure balance method. A molecular weight of 122.12 g/mol was entered into the SRG program for the vapor pressure measurements of benzoic acid.

An approximately 0.5-gram sample of the test substance was used for vapor pressure determination at each temperature. A molecular weight of 432.59 g/mol was entered into the SRG program for the vapor pressure measurement of the test substance. The pressure increase of the test substance at each test temperature was monitored by the SRG at 30 second intervals. The vapor pressure of the test substance was measured three times at 20° and 30°C ± 1°C.

GLP compliance:

yes

Type of method:

spinning rotor

Specific details on test material used for the study:

The test substance, CAS# 151840-68-5, was received on April 5, 2018. The material was identified on the label as: BIS(1,3-N-BUTYLMETHYLCYCLOPENTADIENYL) ZIRCONIUM DICHLORIDE, and was assigned EAG Laboratories identification number 14621 and transferred to ambient storage conditions in darkness. Accompanying correspondence clarified that BIS(1,3-N-BUTYLMETHYLCYCLOPENTADIENYL) ZIRCONIUM DICHLORIDE was the same as CAS# 151840-68-5 and described it as a the solid material. Label information and the Certificate of Analysis (Appendix II) provided the following information:

Chemical Name: Bis(1,3-n-butylmethylcyclopentadienyl)zirconium dichloride
Lot Number: BSC-328-3P-0121
CAS Number: 151840-68-5
Appearance: Off-white to tan solid
Purity: 99.7% (H NMR)
Molecular Formula: C20H30Cl2Zr
Formula Weight: 432.59 g/mol
Expiration Date: Not Provided

Key result

Test no.:

#1

Temp.:

20 °C

Vapour pressure:

0 Pa

Test no.:

#2

Temp.:

30 °C

Vapour pressure:

0 Pa

Conclusions:

The vapor pressure of CAS# 151840-68-5 was determined at two temperatures, 20° and 30°C, using the spinning rotor gauge method. The results of the vapor pressure testing are presented below:

Test
Temperature(°C) Mean Vapor Pressure (Pa) Standard Deviation (Pa) Coefficient of Variation(CV) Number of Measurements (N)
20 ± 1 1.90 x 10-4 3.0 x 10-5 16% 3
30 ± 1 1.42 x 10-4 2.1 x 10-5 15% 3

Executive summary:

The vapor pressure of CAS# 151840-68-5 was determined at two temperatures, 20° and 30°C, using the spinning rotor gauge method. The results of the vapor pressure testing are presented below:

 

Test Temperature (°C)	Mean Vapor Pressure (Pa)	Standard Deviation (Pa)	Coefficient of Variation (CV)	Number of Measurements (N)
20 ± 1	1.90 x 10^-4	3.0 x 10^-5	16%	3
30 ± 1	1.42 x 10^-4	2.1 x 10^-5	15%	3

 

The variations in the vapor pressure measurements at 20° and 30°C temperature conditions were within the expected repeatability variation of the SRG method (i.e. 10 to 20%). However, since the vapor pressures of the test material were very close to the background vapor pressure measurements at each testing temperature, the vapor pressure of the test material at 20° and 30°C will be considered less than the recommended range of the SRG method (i.e. 1 x 10^-4Pa).

Description of key information

The vapor pressure of CAS# 151840-68-5 was determined at two temperatures, 20° and 30°C, using the spinning rotor gauge method. The results of the vapor pressure testing are presented below:

 

Test Temperature (°C)	Mean Vapor Pressure (Pa)	Standard Deviation (Pa)	Coefficient of Variation (CV)	Number of Measurements (N)
20 ± 1	1.90 x 10^-4	3.0 x 10^-5	16%	3
30 ± 1	1.42 x 10^-4	2.1 x 10^-5	15%	3

 

The variations in the vapor pressure measurements at 20° and 30°C temperature conditions were within the expected repeatability variation of the SRG method (i.e. 10 to 20%) (1,2). However, since the vapor pressures of the test material were very close to the background vapor pressure measurements at each testing temperature, the vapor pressure of the test material at 20° and 30°C will be considered less than the recommended range of the SRG method (i.e. 1 x 10^-4Pa).

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

20 °C