Abstract
A 40ml of phenol was put in 100ml two neck round-bottom flask equipped with a conventional distillation device and a ground glass stopper, and heated to the boiling point of phenol, 180°C. During this treatment, a slight amount of water contained in phenol was eliminated from phenol as the azeotropic vapor mixture of phenol and water at 99.5°C, and phenol was thoroughly dehydrated. After the distillation device was replaced by a reflux condenser, a piece of magnesium metal sample was put quickly into the flask through the side neck. Then the content was heated under stirring at 180°C, until magnesium metal diminished completely in phenol, forming magnesium phenoxide, while magnesium oxide remained as residue. The reaction mixture was cooled to (5060) °C, and anhydrous methanol was added to keep phenol and magnesium phenoxide in dissolving form. The residual magnesium oxide was caught on a sintered glass filter (1G5) and dissolved in 50ml of 2M hydrochloric acid. The solution was diluted to a definite volume and magnesium in the solution was determined by the atomic absorption spectrometry. All the experiments were carried out in a glove box in dry nitrogen atmosphere to avoid the influence of oxygen and water from air. By the above procedure a minute amount of magnesium oxide could be determined precisely with high reproducibility. To clarify the behaviors of magnesium metal and magnesium oxide in this separation process additional experiments were also done.
