Dimethyl ether

Endpoint summary

Additional information

The test substance (CAS No. 115-10-6) is a gas.
Conversion factors: 1 ppm = 1.91 mg/m3 (at 20°C and 760 mmHg); 1 mg/m3 = 0.523 ppm

The freezing point was not measured in accordance with Column 2 adaptation statement of REACH Annex VII, information requirement section 7.2, since this study does not need to be conducted below a lower limit of -20°C. Since this substance is a gas with a literature/measured melting/freezing point of -141.5°C (Lide DR (ed.), 2009), measurement of this property is not required.

The boiling point was not measured in accordance with Column 2 adaptation statement of REACH Annex VII, information requirement section 7.3, this study does not need to be conducted since the substance is a gas. The literature value for the boiling point is  -24.8 °C (Lide, 2009), indicating the substance is a gas.

Density was calculated to be 0.00188 g/cm³. In accordance with column 2 of REACH Annex VII, information requirement section 7.4, a relative density study does not need to be conducted as the substance is a gas. An estimation based on calculation was made from molecular weight and the Ideal Gas Laws, ρ = m/V. At 1 atm and 25°C (298.15 K), 1 mol of dimethyl ether has the volume of 24.45 L and the molecular weight is 46.07. Therefore, ρ = 46.07/24.45 = 1.88 g/L = 0.00188 g/cm³.

Granulometry was not conducted in accordance with Column 2 adaptation statement of REACH Annex VII, information requirement section 7.14, this study does not need to be conducted for gases.

The vapour pressure was determined to be 513291 Pa at 25°C (MPBPWIN version 1.43). The octanol/water partition co-efficient (log Kow) was determined to be 0.07 (calculated using KOWWIN version 1.67). Supporting documentation for these calculations is documented using the QSAR Prediction Reporting Format (QPRF) version 1.1, May 2008 and the QSAR Model Reporting Format (QMRF) version 1.2, July 2007. 

The water solubility is reported as 45.6 g/L at 760 torr and 25^oC as measured in a closed system (Hine J and Weimar RD, 1965). The substance is highly miscible with water and this value will increase under increased pressure.  However, under environmental conditions, in open systems, the high volatility would decrease the amount of substance in water.

Surface activity is not a desired property of the material. In accordance with Column 2 adaptation statement of REACH Annex VII, information section requirement 7.6, surface tension measurement does not need to be conducted since, based on structure, surface activity is not expected and no surface-active properties would be predicted for this compound.

No flash point measurement was conducted. In accordance to REACH Annex XI Section 2, with reference to the guidance mentioned in REACH Art 13(3) the test guidance "ECHA guidance on Information requirements and chemical safety assessment Chapter R.7a Endpoint specific guidance" needs to be respected. This guidance indicates that flash point does not need to be conducted for substances that are solids or gases at room temperature.

The hot flame Auto-Ignition Temperature (AIT) of the test substance is 226°C as determined by EC Testing Method A15 (DuPont-18691-388).

The test substance is an extremely flammable gas based on the flammability limits of 3.3 - 26.2 % volume in air, as reported in literature (Kondo S et al., 2006; measured by ASTM E-681). Recent testing (BASF, 2021) to confirm the lower explosion limit (LEL) has shown the LEL to be 3.2%.

The test substance is non-explosive.  In accordance with Column 2 adaptation statement of REACH Annex VII, information requirement section 7.11, explosivity testing does not need to be conducted based on a structural assessment of the substance. Examination of the structure indicates that there are no groups associated with explosive properties.

The test substance is non-oxidising. In accordance with Column 2 adaptation statement of REACH Annex VII, information requirement section 7.13, this measurement of oxidising properties does not need to be conducted based on structural assessment of the substance. The substance contains no oxidising groups and all oxygen atoms are bonded directly to carbons. Auto-oxidation of DME hardly occurs. Methyl groups are very stable and are poorly oxidizable. In contrast, auto-oxidation DEE is 100 times higher than for DME. There is no evidence for formation of peroxides below 100°C.

Measurement of stability in organic solvents was waived.  In accordance with REACH Annex XI Section 2, with reference to the guidance mentioned in REACH Art 13 (3) the test guidance “ECHA guidance on information requirements and chemical safety assessment Chapter R.7a Endpoint specific guidance” needs to be respected. This guidance indicates that this study does not need to be conducted since the stability in organic solvents is not considered critical. This would be assessed in individual studies where organic solvents are used.

Measurement of dissociation constant is not technically feasible. In accordance to REACH Annex XI Section 2, with reference to the guidance mentioned in REACH Art 13(3) the test guidance "ECHA guidance on Information requirements and chemical safety assessment Chapter R.7a Endpoint specific guidance" needs to be respected. This guidance indicates that measurement of pKa is irrelevant as the substance cannot dissociate due to a lack of relevant functional groups.

Measurement of viscosity is not required. In accordance to REACH Annex XI Section 2, with reference to the guidance mentioned in REACH Art 13(3) the test guidance "ECHA guidance on Information requirements and chemical safety assessment Chapter R.7a Endpoint specific guidance" needs to be respected. This guidance indicates that viscosity measurement is only relevant to liquids.