Calcium cyanamide

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the melting point is above 300°C

Reference 2

Endpoint:

vapour pressure

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Available experimental vapour pressure data for cyanamide are used in a read-across approach for the environmental assessment of calcium cyanamide.
For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

Reason / purpose for cross-reference:

read-across source

Key result

Temp.:

20 °C

Vapour pressure:

0.51 Pa

Remarks on result:

other: 0.51 Pa = 68 mm Hg

Temp.:

25 °C

Vapour pressure:

1 Pa

Remarks on result:

other: 1.0 Pa = 133 mm Hg

From the data obtained in the assay (the masses of the condensed sample and opening times of the aperture in different temperatures, 21 -25.2°C), a vapour pressure curve was established by plotting the logarithm of the vapour pressure versus the reciprocal temperature. From this plot the vapour pressures for 20 and 25°C were calculated.

Conclusions:

Cyanamid F1000 vapour pressure:
P20°C = 0.51 Pa = 68 mm Hg
P25°C = 1.0 Pa = 133 mm Hg

The available experimental vapour pressure data for hydrogen cyanamide are used in a read-across approach for the assessment of calcium cyanamide.
Upon dissolution in water calcium cyanamide is fast transformed to hydrogen cyanamide. Thus, upon release of calcium cyanamide via wastewater streams the environmental distribution and exposure is driven by the physico-chemical/fate properties of hydrogen cyanamide.

Executive summary:

The vapour pressure of Cyanamid F1000 was measured by the vapour measure balance method according to the EU method A.4, in 4 different temperatures between 21 and 25.2 °C. The following vapour pressure for Cyanamid F1000 was calculated:

P20°C = 0.51 Pa = 68 mm Hg

P25°C = 1.0 Pa = 133 mm Hg

Description of key information

In accordance with column 2 of REACH Annex VII, the test on vapour pressure (required in section 7.5) does not need to be conducted as the melting point of calcium cyanamide is above 300 °C.

However, a numerical value for vapour pressure is required for environmental exposure calculations. Therefore, available experimental results for the structural analogue cyanamide are used in a read-across approach:

Cyanamid F1000 vapour pressure:

-       T = 20°C: VP = 0.51 Pa (68 mm Hg)

-       T = 25°C: VP = 1.0 Pa (133 mm Hg

The value of 0.51 Pa at 20 °C is carried forward as key value for environmental risk assessment.

Key value for chemical safety assessment

Vapour pressure:

0.51 Pa

at the temperature of:

20 °C

Additional information

The vapour pressure of Cyanamid F1000 was measured by the vapour measure balance method according to the EU method A.4, in 4 different temperatures between 21 and 25.2 °C.

Available experimental vapour pressure data for cyanamide are used in a read-across approach for the assessment of calcium cyanamide:

Upon dissolution in water calcium cyanamide is fast transformed to hydrogen cyanamide. Thus, upon release of calcium cyanamide to water the environmental distribution and exposure is driven by the physico-chemical/fate properties of cyanamide.