Characteristics of different types of glycerol

Glycerol is similar to water and simple aliphatic alcohols in solubility because of the presence of OH root. It can be completely miscible with water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-amyl alcohol, ethylene glycol, propylene glycol and phenol. The solubility in acetone at room temperature is 5% of the weight of acetone. The soluble glycerol in 100% ethyl acetate is 9. There is also a limited solubility in dioxane and ether, but glycerol is almost soluble in high molecular weight aliphatic alcohols, oils, hydrocarbons and chlorinated solvents such as hexane, benzol and chloroform. It can be completely miscible with ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, but its solubility in ethylene glycol monomethyl butyl ether is limited. The introduction of hydroxyl and amino groups into aliphatic and aromatic hydrocarbons increases the miscibility with glycerol, but the introduction of alkyl groups decreases the miscibility with glycerol. If the alkyl chain of secondary or tertiary amine of monoamine increases, the miscibility of the compound with glycerol decreases. Heterocyclic compounds containing one nitrogen atom are usually easily miscible with glycerol. The solubility of gases in glycerol, as in other liquids, is related to pressure and temperature.

The surface tension of 99% glycerol is about 52 dynes/cm at 30℃. The surface tension of glycerol is less than that of water, but greater than that of most liquid organic compounds. The surface tension of glycerol decreases with temperature and height. The surface tension of glycerol increases slightly after adding water, but decreases significantly after adding ethanol.

Commodity glycerol can be divided into crude glycerol and refined glycerol. Refined glycerol, or distilled glycerol, can be divided into several grades. The United States classifies refined glycerol into the following grades:

American Pharmacopoeia Glycerol, which meets the chemical pure glycerol standard of American Pharmacopoeia. It is mainly used in food, medicine and industries requiring high purity glycerol.

High specific gravity glycerol is industrial pure glycerol with glycerol content not less than 98.7%.

Explosive glycerin is produced according to the special requirements of nitroglycerin and Dana explosive manufacturer. Its concentration is similar to that of high specific gravity glycerin.

Yellow distilled glycerol is used in industries where the purity, specific gravity and concentration of glycerol are not required.

Glycerol is one of the important nutrients of bacteria, yeasts and moulds. Glycerol is widely used as a fungicide or to inhibit the production and reproduction of microorganisms when it is used as a nutrient in high concentrations. The effect of glycerol as a fungicide is probably due to the extraction of water from bacterial cells.

The recommended standard for glycerol industry in China is GB/T 13206-2011. Each company’s glycerol products have its own enterprise standards on the basis of meeting relevant national standards.

The main sources of glycerol are Malaysia, Indonesia, Thailand and other countries.

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