EU A.2: Boiling temperature

The boiling point of a substance is an environmentally relevant physical chemical property because it is important for identification purposes and is one factor influencing the states in which the substance will exist in the environment.

The purpose of this study is to evaluate the boiling point by the capillary method using an electronic controlled heating system.

Study Design

Course of the test

Apparatus - Büchi B 545

The boiling point will be determined using a Büchi B 545 boiling point device. The temperature range of the device is from room temperature up to 400 °C. The boiling temperature is that temperature at which, on momentary cooling, the formation of bubbles stops and the liquid suddenly rises in the capillary.

For the determination of the boiling point, the capillary method according to Siwoloboff will be used. A small amount of the test item will be heated in the electronic controlled sample block and the temperature of around the sample will be displayed. The sample will be observed visually while raising the temperature. A phase transformation from liquid to vapour usually is deduced by the formation of steam bubbles leaving the inserted boiling capillary.

Preliminary test

The boiling behaviour of the test item will be estimated in a preliminary test. Therefore, a sample of the test item in a glass tube will be heated from room temperature up to about 400 °C with a rate of approximately 10 °C/min unless a phase transition or reaction of the test item will be observed.

Main test

If in the temperature range investigated in the preliminary test, a phase transition of the test item is observed, the experiment will be repeated with a new test item aliquot in the immediate vicinity of the temperature of the phase transition observed. For the actual determination of the boiling point, the temperature rise will be adjusted to a rate less than of 1 °C/min at about 15 °C before and after the predetermined phase transition temperature.


The boiling temperature [°C and K] at 20 °C will be reported.

In case of boiling point cannot be determined, because of decomposition or sublimation, the temperature at which the decomposition or sublimation is suspected - will be reported.

Guidelines and literature

  • Commission Regulation (EC) No 440/2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) (originally published as Council Regulation (EC) No 440/2008, corrigendum according to Official Journal of the European Union (EN) dated June 3, 2008, L 143/55), Annex, Part A, A.2.: “Boiling Temperature”, Official Journal of the European Union, L 142, Volume 51, 31 May 2008
  • Organisation for Economic Co-operation and Development (OECD), Guidelines for Testing of Chemicals, Guideline No. 103, “Boiling Point”; adopted July 27, 1995