Glycerins - is that? Properties and applications of the substance. How to make glycerine?

Glycerin is a triatomic alcohol. It is used in medicine, food industry, cosmetology and even for the preparation of dynamites. What properties does glycerin have? Can I get it at home?

What is glycerin?

Glycerol is an organic substance and is a triatomic alcohol. Its chemical form looks like C ₃ H ₈ O ₃ or HOCH ₂ -CH (OH) -CH ₂ OH. The meaning of the word glycerin is directly related to its properties. The name comes from the Greek word "glycos", or "sweet", because of the sweet taste of the substance.

Glycerin is a clear liquid, quite viscous and absolutely odorless. It is non-toxic and non-toxic, so there is no danger in direct contact with the skin. In the natural environment, glycerol is part of animal fats, and is also found in most vegetable oils. Its insignificant part is in the blood of animals.

For the first time glycerin was discovered in 1783, when chemist Karl Scheele was engaged in saponification of fats with the help of lead oxide. During the heating of the oxide with olive oil, a soap solution began to form. After its evaporation, a viscous sweetish syrup was formed.

Properties

The substance has an increased hygroscopicity, that is, the ability to absorb moisture and retain it. The temperature of its boiling is 290 degrees Celsius. On boiling, glycerol partially decomposes. At a temperature of 362 degrees, it can self-ignite. Under normal conditions, the substance does not have volatile properties, but evaporates when heated. Combustion is accompanied by the release of water and carbon dioxide.

Glycerin is insoluble in fats, hydrocarbons and arenes, but it dissolves perfectly in water and alcohols. When added to water, a shrinkage or a decrease in the volume of the solution takes place, and the temperature rises. In such a mixture, the freezing point of water decreases.

When interacting with mineral and carboxylic acids, glycerol forms esters. At their core, they are fats involved in the metabolic process and perform important biological functions in the animal body. Some of them are, for example, phospholipids.

The ester is also trinitroglycerin. The substance is formed from the combination of glycerin with nitrous acid. It is an oily toxic and highly explosive liquid, sensitive to the slightest manipulation.

Glycerin and copper hydroxide form a solution of dark blue color with complete dissolution of the precipitate, which indicates the acid properties of the alcohol. Glycerol is able to dissolve aromatic alcohols, alkalis, sugars, salts and other organic and inorganic compounds.

Methods of obtaining

The very first method of obtaining glycerin in history is saponification. He appeared immediately after the discovery of the substance by the chemist Scheel. The result of this process is a soapy solution with glycerin. After that, they should be separated from each other, which is done with the help of sodium chloride. Then glycerin must be thickened and purified by distillation or activated carbon.

Another method involves adding water to the oil. At a certain pressure, they are heated and stirred for ten hours, and then cooled. After cooling, the substances are clearly divided into several layers: in the lower - glycerin with water, in the upper - acids.

The substance is also obtained by hydrolyzing carbohydrates, for example, starch, cane sugar. But then not pure liquid is formed, but a mixture with different glycols.

All these methods help to get, so-called, food glycerin. It is harmless to humans and is added for the preparation of certain products. In contrast, there is a technical glycerine. This substance is obtained not from vegetable and animal raw materials, but from propylene, a combustible gas with a strong narcotic effect.

Application

Both food and technical glycerin are widely used in our lives. It is often used to make synthetic resins. Nitroglycerin is used to produce dynamite and other explosives. In medicine, the same substance is excellent for drugs that dilate blood vessels.

In the industry it is used for the manufacture of paper, detergents. In the production of electrical and radio engineering during soldering, it serves as a flux. Glycerin is used for the manufacture of plastics, building varnishes and paints.

In the food industry it is registered as an additive Е422. It is an emulsifier, which is needed to increase the viscosity, as well as to create various mixtures. The substance is a part of numerous medicines, it is used for cartridges of electronic cigarettes, for making candles. In biology, glycerol is necessary for the preservation of tissues, organs, organisms and anatomical preparations.

Glycerin in cosmetics

Due to the fact that glycerin retains moisture, it is often used in various cosmetics for skin care and hair. It is present in soap, in nourishing and moisturizing creams.

The substance penetrates the epidermis, holding water in the cells. Thus, it does not allow the skin to become too dry and lifeless. But he also has disadvantages. The fact is that in an atmosphere with a very dry air (less than 65% moisture), glycerin begins to absorb moisture from the skin, further drying it.

Usually, cosmetologists do not recommend using it in the winter. In addition, proportions are important. In small amounts, the presence in the cream of glycerin only improves the properties of the skin. Together with other products it is used in home recipes for masks and lotions. For example, in combination with orange and water for toning and cleansing the skin, for hair use with eggs, honey, castor oil and other ingredients.

How to make glycerine?

It is not necessary to buy glycerin. It can also be prepared at home. To do this, you need animal fat (1.9 kg), alkali (342 mg), water (995 mg) and salt. Fat can be taken from the meat of any animal, cleansing it of all veins and vessels. And then we act like this:

• We melt the pieces of fat on a small fire;
• Let it cool down to 35 degrees;
• In a separate bowl we prepare alkali, pouring it into the water;
• The temperature of the alkali must also reach 35 degrees, then gently pour it gently into the pan with the fat;
• Quickly stir the ingredients, while adding salt;
• Continue "salt" and stir until the mixture begins to divide into a clear liquid below and a cloudy solution at the top;
• We catch the entire top layer - it's soap, the bottom layer - glycerin;
• Strain the glycerin through a sieve or gauze to remove small particles of soap.

To be engaged in the preparation of glycerin should be very carefully. When diluted with water, the alkali is heated above 90 degrees. Work should be in gloves, glasses (from fumes), and build alkali in a special container.