Hexamethylene diisocyanate, trimers, reaction products with 2-hydroxyethyl acrylate

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 Oct - 13 Nov 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Version / remarks:

adopted in 2006

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Version / remarks:

adopted in 2008

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7950 (Vapor Pressure)

Version / remarks:

adopted in 1996

GLP compliance:

yes (incl. QA statement)

Remarks:

Hess. Ministerium für Umwelt, Energie, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Type of method:

effusion method: Knudsen cell

Specific details on test material used for the study:

Storage conditions: Ambient temperature, keep container tightly closed, protected from sunlight

Temp.:

ca. 20 °C

Vapour pressure:

0 hPa

Remarks on result:

other:

Remarks:

Calculated by extrapolation of the measured vapour pressure curve for the temperatures 20, 25 and 50 °C.

Temp.:

ca. 25 °C

Vapour pressure:

0 hPa

Remarks on result:

other:

Remarks:

Calculated by extrapolation of the measured vapour pressure curve for the temperatures 20, 25 and 50 °C.

Temp.:

ca. 50 °C

Vapour pressure:

0 hPa

Remarks on result:

other:

Remarks:

Calculated by extrapolation of the measured vapour pressure curve for the temperatures 20, 25 and 50 °C.

Key result

Transition / decomposition:

yes

Remarks:

decomposition

Transition temp.:

>= 180 - <= 260 °C

Results
Thermal Stability
An endothermic effect was seen in the temperature range of 30 to 50 °C. An exothermic effect was seen in the temperature range of 180 to 260 °C, with a decomposition energy of -120 J/g.

Table 1 – DSC measurement results

Sample weight [mg]	Start [°C]	Energy [J/g]
11.20	30 (endo) 180 (exo)	10 -120

 

Effusion method – Knudsen cell
In the first measurement the vapour pressure was measured in the temperature range of 10 to 25 °C, results are shown in table 2.

Table 2 – Effusion method results (1^stmeasurement)

No.	Temperature [°C]	Vapour pressure [Pa]
1	10	4.11E-04
2	15	1.13E-03
3	20	3.07E-03
4	25	5.60E-03

 

As the test item has a high molecular weight of ca. 850 g/mol and it is nearly solid at room temperature, a second measurement was done at higher temperatures. With this, it could be estimated if the vapour pressure values measured in the first series were caused by any low molecular substances, whose evaporation was detected. In the second measurement, the vapour pressure was measured in the temperature range of 81 to 101 °C, see Table 3.

Table 3 – Effusion method results (2^ndmeasurement)

No.	Temperature [°C]	Vapour pressure [Pa]
1	81	6.00E-04
2	91	9.23E-04
3	101	1.80E-03

 

Discussion
The second measurement showed that the vapour pressure from the first measurement was due to the evaporation of low molecular components or impurities. Therefore, the results from the second measurement series were used for the final evaluation.

Although only three segments could be interpreted, the data point of the second measurement can be assigned to the vapour pressure of the test item. From the three measured data points of the second vapour pressure curve, the constants A and B of the Antoine equation (Equation 2) can be derived by regression to:
A = 5.6569
B = -3150.27
C = 273.15

Conclusion
The vapour pressure of the test item calculated by extrapolation of the measured vapour pressure curve for the temperatures 20, 25, and 50 °C is shown in Table 4.

Table 4 – Calculated vapour pressure values

Temperature [°C]	Vapour pressure [Pa]
20	8.1E-06
25	1.2E-05
50	8.1E-05

Description of key information

8.1E-08 hPa at 20 °C

1.2E-07 hPa at 25 °C

8.1E-07 hPa at 50 °C

(OECD 104, extrapolated from measured data)

Key value for chemical safety assessment

Vapour pressure:

0 hPa

at the temperature of:

25 °C

Additional information

Vapour pressure values were calculated using a linear regression equation.