This method is applicable to determine the water-soluble acids or alkalis of liquefied petrolatum products, additive, lubricating grease, paraffin wax, ozocerite and component containing wax.
1 Summary of Test Method
Extract the water-soluble acids or alkalis in test sample with distilled water or ethanol water solution, after that, check the color change situation of the extracted fluid with methyl orange or phenolphthalein indicator respectively or determine the pH value of the extractive with an acidimeter so as to judge if there is any water-soluble acid or alkali.
2 Apparatus
2.1 Separating funnel: 250 or 500mL.
2.2 Test tube: of a 15~20mm diameter and a 140~150mm height, made of flint glass.
2.3 Funnel: ordinary glass funnel.
2.4 Measuring cylinder: 25, 50 and 100mL.
2.5 Conical flask: 100 and 250mL.
2.6 Porcelain evaporating dish.
2.7 Electric hot plate and water bath.
2.8 Acidimeter: it is provided with glass-silver chloride electrode (or glass-calomel electrode), the accuracy is pH ≤0.01pH.
3 Reagents and Materials
3.1 Reagents
3.1.1 Methyl orange: prepared into 0.02% methyl orange aqueous solution.
3.1.2 Phenolphthalein: prepared into 1% phenolphthalein ethanol solution.
3.1.3 95% ethanol: analytically pure.
