Zinc di(benzimidazol-2-yl) disulphide

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-02-21 to 2017-04-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

adopted 23 March 2006

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Version / remarks:

24 August 2009

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7950 (Vapor Pressure)

Version / remarks:

Au-gust 1996

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

effusion method: Knudsen cell

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and batch No. of test material: OUCHI SHINKO CHEMICAL INDUSTRIAL CO., LTD.; 608011
- Expiration date of the lot/batch: 2017-08-31

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Keep to the storeroom with suitable ventilation. Avoid fire, direct sunlight and moisture. Store at room temperature.

Key result

Temp.:

20 °C

Vapour pressure:

0 Pa

Temp.:

25 °C

Vapour pressure:

0 Pa

The following vapour pressures were determined experimentally and considered as valid (mean and standard deviation given):

Table 1 Experimentally Determined Vapour Pressures

T	T	P	Stand. Dev. P	RSD P
°C	K	Pa	Pa	%
120.0	393.2	4.05E-03	1.05E-03	25.9%
135.0	408.2	8.35E-03	1.54E-03	18.4%
150.0	423.2	1.27E-02	2.84E-03	22.3%

In this table, E-0X represents multiplication with 10^-X.

The vapour pressure was calculated for the test substance using the following equation;

p = (m/KAt) (2πRT/M)^1/2

with

Table 2 Equation Parameters

Parameter	Explanation	Source/Value
p	vapour pressure in Pa	to be calculated
m	weight loss in kg	-
t	time in s	-
A	area of aperture in m²	7.854 * 10E-07 m²
K	correction factor	0.909
R	universal gas constant in J/Mol*K	8.314472
T	temperature in K	-
M	molecular weight in kg/Mol	0.36377

The correction constant is depending on the relation length/radius of the aperture of the Knudsen cell and is stated in the literature as follows:

Table 3 Correction Constant

Relation	0.1	0.2	0.4	0.5	0.6	0.8	1.0
K	0.952	0.909	0.834	0.801	0.771	0.718	0.672

With the chosen length of the aperture 0.1 mm and the chosen radius 0.5 mm, a relation of 0.2 was calculated, and a correction factor of 0.909 was chosen.

Table 4 Parameters of Linear Regression

Parameter	Value
Slope	-2759.8
Intercept	4.6449
Correlation Coefficient r	-0.9915
Coefficient of Determination r2	0.9831

Conclusions:

The vapour pressure of the test item was calculated by extrapolation of the measured vapour pressure curve for the following temperatures:
for 20 °C: 1.70E-5 Pa
for 25 °C: 2.45E-5 Pa

Executive summary:

The vapour pressure was determined according to OECD guideline 104 (LAUS, 2017). The vapour pressure of the test item was determined at nine different temperatures (30, 45, 60, 75, 90, 105, 120, 135 and 150 °C) using the effusion method (weight loss). Experiment 1, 2, 3, 4, 5 and 6 (nominal temperature 30, 45, 60, 75, 90 and 105 °C) showed no reproducible weight loss. When visible contaminations, caused by explosive evaporation of the test item, were observed, the cells were meticulously cleaned and weighed. This weight was used as initial weight for the subsequent measurements. To avoid bias, these measurements were not used for calculations.

Three experiments could be evaluated as they showed relevant and reproducible weight loss. All evaluated experiments showed sufficient reproducibility, giving relative standard deviations of less than 26 % and good correlation. Therefore, the result of the test can be considered valid.

For the three measured temperatures, 1/T was plotted against log (P).

Vapour Pressures (Effusion Method)

Experiment	T	Mean P	Stand. Dev. P	RSD P
No.	K	Pa	Pa	%
7	393.2	4.05E-03	1.05E-03	25.9%
8	408.2	8.35E-03	1.54E-03	18.4%
9	423.2	1.27E-02	2.84E-03	22.3%

In this table, E-0X represents multiplication with 10^-x.

Stand. Dev. = Standard Deviation; RSD = Relative Standard Deviation

The graph 1/T vs. log (P) shows a straight line with a correlation coefficient of - 0.9915. For the test item, the following vapour pressures at 20 °C and at 25 °C were calculated from the regression equation:

Vapour pressure at 20 °C:          1.70* 10E-05 Pa

Vapour pressure at 25 °C:          2.45* 10E-05 Pa

Description of key information

The vapour pressure of the test item was calculated by extrapolation of the measured vapour pressure curve for the following temperatures:

for 20 °C: 1.70E-5 Pa

for 25 °C: 2.45E-5 Pa

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

20 °C

Additional information

The vapour pressure was determined according to OECD guideline 104 (LAUS, 2017).The vapour pressure of the test item was determined at nine different temperatures.

Three experiments could be evaluated as they showed relevant and reproducible weight loss. All evaluated experiments showed sufficient reproducibility, giving relative standard deviations of less than 26 % and good correlation. Therefore, the result of the test can be considered valid.

For the three measured temperatures, 1/T was plotted against log (P). The graph 1/T vs. log (P) shows a straight line with a correlation coefficient of - 0.9915. For the test item, the following vapour pressures at 20 °C and at 25 °C were calculated from the regression equation:

Vapour pressure at 20 °C:          1.70* 10E-05 Pa

Vapour pressure at 25 °C:          2.45* 10E-05 Pa