Formaldehyde solutions for industrial use -- Determination of methanol content
The results obtained by this method will include the methanol freed from combined forms. These are however not usually present at higher levels to effect the results. The principle consists in esterfication of the methanol present with formic acid using sulphuric acid as a catalyst. Distillation of the methyl formate into sodium hydroxide solution and back-titration of the excess sodium hydroxide with a standard volumetric sulphuric acid solution, using phenolphthalein as indicator. This method is intended for methanol contents greater than 0,2 %.