It is understood: paraffin, colorless to white translucent lumps, Pure paraffin is white, while paraffin containing impurities is yellow, tasteless, odorless, and greasy. Soluble in ether, chloroform, benzene, petroleum ether, volatile oil or various fatty oils, slightly soluble in ethanol. It has stable chemical properties and does not react with acids, alkalis, oxidants and reducing agents. It will turn yellow under ultraviolet irradiation, can burn and decompose, and is stable at room temperature.
The inspection methods of paraffin are as follows:
PH:
Take this product for about 5.0g, after heating and melting, add an equal volume of neutral hot ethanol, shake it, and let it stand for stratification; the ethanol solution should show a neutral reaction when it meets litmus paper.
Easy to carbonize:
Take 4.0g of this product, place it in a stoppered test tube, melt it in a water bath at 65-70°C, add 95% (g/g) 5ml of sulfuric acid, and maintain this temperature for 10 minutes. Shake vigorously for a few seconds every 1 minute. Take it out after 10 minutes. This product must not be dyed. If the sulfuric acid layer develops color, mix it with the control solution (take the colorimetric gasification 0.8ml of cobalt liquid, 0.3ml of colorimetric copper sulfate liquid, 1.0ml of colorimetric potassium dichromate liquid and 2.9ml of water) should not be darker.
Sulfide:
Take 4.0g of this product, add 2 drops of saturated lead oxide sodium hydroxide solution (1-5), and add 2mh of ethanol Shake well, heat in 70X: water bath for 10 minutes while shaking. After cooling, it should not appear dark brown.
Condensed aromatic hydrocarbons:
Take 0.5g of this product, weigh it accurately, place it in a separatory funnel, add 25ml of n-hexane and shake to dissolve. Then add 5ml of dimethyl sulfoxide precisely, shake vigorously for 2 minutes, let it stand to separate the layers, move the dimethyl sulfoxide layer to another separatory funnel, add 2ml of n-hexane, shake and wash, and let it stand. Separate the layers (centrifuge if necessary), and separate the dimethyl sulfoxide layer as the test solution; take another 25 ml of n-hexane, place it in a separatory funnel, add 5 ml of dimethyl sulfoxide accurately, and shake vigorously for 2 minutes. Let it stand for stratification, take the dimethyl sulfoxide layer as the blank solution, and measure the absorbance in the wavelength range of 260 to 350nm according to UV-visible spectrophotometry (General Chapter 0401). The maximum absorbance shall not exceed 0.10.
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