11-aminoundecanoic acid

Boiling point

Description of key information

Due to the phenomenons observed in the study available, it is not possible to conclude to any valid result: 11-aminoundecanoic acid decomposes and/or polymerises before boiling.

Additional information

The boiling point of 11 -aminoundecanoic acid has been determined according to the OECD Guideline 103, using a Differential Scanning Calorimetry (DSC) device.

The results of the 1st test temperature rise ( from 140°C to 300°C at 10°C/min) showed a first endothermic transition of relative irreversible fit to a departure of vaporization constituent, this phenomenon was observed here since the passage of the solid state to liquid, in the domain of temperature understood between 184°C and 240°C. Nevertheless, this transition came with an abnormally incomplete mass loss of the sample, that did not allow to validate the boiling point measure of this compound. Moreover, it was noted that during the vaporization stage of the liquid phase, an evolution of the viscosity as well as a light discoloration of the solution passing from colourless to yellow-brown atoccured. It could be either polycondensation or beginning of decomposition.

For the second sweep in temperature (cool from 300°C to 140°C at 20°C/min followed by heat from 140°C to 300°C at 10°C/min), a first increase in temperature up to 300°C allowed to detect the presence of a characteristic endotherm of a residual melting. Nevertheless, the observed phenomenon did not allow to validate the reversibility of this first order transition.

An exploratory DSC test was also achieved on the test item, up to a temperature of 500°C. The thermogram obtained in this test revealed the presence of a second vaporization endothermal transition visible at the extrapolated initial temperature of 467°C. This transition happened with a total discoloration of the solution, from the clear yellow-brown to the dark brown. The formation of bubbles was noted too, as well as the foaming of the "liquid" phase, similar to a boiling point.

These phenomenons can be attributed to polymerisation and/or decomposition of the test substance instead of boiling. Therefore, it is not possible to conclude to any valid result.

Besides this experimental data, two estimated values are available. The first one was estimated to be 193.7°C according to the calculation Meissner’s method. This calculated value seems to be in adequacy with the first temperature vaporization zone of this material observed by DSC between 184°C and 245°C, but can not be attributed to boiling. The second value is an EPIWIN estimation -based on the structure- which concluded to a value of 480°C.

Based on this data, it is considered that 11-aminoundecanoic acid decomposes or polymerises before boiling. Therefore, no boiling point can be determined.