Absolute alcohol. Industrial production of alcohol from biological raw materials

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Absolute ethyl alcohol has found its application in industry. This substance is necessary to ensure the reaction of organic synthesis. Such a liquid is now often used in laboratories. For the first time, the technical specifications dedicated to this substance were published in the 37th year. Currently, there are specialized GOSTs and standards that regulate the quality of the liquid and the nuances of its preparation.

General information

As defined in 1937, absolute alcohol is a liquid that is estimated to be 99.7% or more ABV. The presence in each 100 grams of up to 5 mg of aldehydes is allowed. When examining a substance for organic acids, all such compounds must be converted to acetic acid. The concentration cannot exceed a milliliter per 100 ml of finished product.

A distinctive feature of absolute alcohol is the absence of any dry residue. This substance cannot contain alkaline compounds, mineral acids. Notthe inclusion of furfural is allowed. Alcohol should be transparent, without any shade and color. It is not inherent in foreign odors, the presence of a specific taste is not allowed.

Nuances of terminology

Modern chemists know not only absolute alcohol, but also anhydrous. These two terms cannot be equated. In the absolute variety, as can be concluded from the above, there may be water, but in small quantities.

The chemical compound under consideration is capable of forming stable bonds during a chemical reaction with gasoline. Due to this, absolute alcohol is used in a number of countries for the production of motor fuel. As studies have shown, if this liquid is mixed with gasoline, the anti-knock qualities of the fuel used to operate the engine become more significant. Therefore, more compression is possible.

Features and shapes

A qualified chemist can tell you about the difference between distillate and rectified. The distillate is obtained by fermentation and distillation, and the rectified product is a product purified from impurities. In addition, when using the rectification technique, it is possible to achieve ready-made ethyl alcohol, the concentration of the main substance in which is up to 95.7%. Such parameters are due to the presence of ethyl alcohol in azeotropic compounds that appear during chemical interaction with water under normal atmospheric pressure.

Usually currently used advising GOST 5964-93 ethyl alcohol. It is he who is most in demand in the national economy. In such a liquid, water is contained in a concentration of 4.43% or a little more. In certain cases, for the reaction to proceed, it is necessary to ensure the presence of alcohol, in which there is practically no water, then they resort to the absolute variety. This is necessary in the manufacture of pharmaceutical products, varnishes and paints. The absolute variety is in demand in the manufacture of cosmetics, perfumes. For the manufacture of the substance, absolutization reactions were developed.

Mistakes and misconceptions

It so happened that the alcohol presented in pharmacies is the very product that first comes to mind, it is worth mentioning at least some alcohol. If ordinary people talk about ethyl alcohol, as a rule, the topic is reduced to a discussion of the strength of the liquid, and some regret that there is no absolute, real alcohol, that is, one that would be 100% alcohol itself, without special diluents and additives. Many are convinced that the maximum strength is 95.6%. In fact, absolute alcohol exists, it's just that chemists mostly know about it, since it was in this industry that it was used.

Some people think: for example, does any Itkul distillery use an absolute product in its work? Make no mistake about this: the absolute liquid is not intended for food purposes, it is used in the manufacturing industry, but not for the manufacture of beverages.

About terms and phenomena

Before you figure out how the products of the same mentioned"Itkulsky distillery" from an industrial product, it is reasonable to orient in the term "fortress" in relation to alcohol-containing liquids. This parameter was introduced to reflect the presence of ethanol in a mixture of alcohol and water. What people are accustomed to calling alcohol is normally a compound with water, and any alcohol used in the food industry necessarily has water in its composition. The content of this substance varies.

The concentration of absolute ethyl alcohol, as follows from the current standards, should be 99.7% or even more, that is, thousandths of a percent are allocated to water in the total volume. For real use, such a product is usually not required; it is unjustified to use it due to the complexity of manufacturing. Even for medical purposes, a strength of 95% is enough, not to mention food use. In rare cases, hydrolysis alcohol must be used.

Where can I get it?

Experienced chemists can tell you how to make alcohol. Specialized enterprises responsible for this process daily produce large volumes of the product of varying degrees of concentration. There are several methods for preparing alcohol, and the most popular option is a natural fermentation reaction. For its implementation, it is necessary to have at its disposal plant products enriched with carbohydrates. Another approach is a hydrolysis reaction using cellulose extracted from straw, wood.

Based on whether hydrolysis alcohol is needed or not, one can resort to the reactionethylene hydration. This word refers to gas. Phosphoric or sulfuric acid is used for the reaction. The chemical interaction that occurs with the combination of these substances is quite complex, the reaction requires the participation of a catalyst, but its efficiency is high enough for the method to become industrially widespread.

Reactions and products

By resorting to the previously described methods of how to make alcohol, you can get at your disposal a product of relatively low concentration. The finished liquid will contain a variety of impurities. To purify the substance and increase the percentage of alcohol content, it is necessary to organize distillation. To do this, you can use a traditional distillation unit or distillation column. A similar installation is used if necessary to process oil. Based on the results of such events, it is possible to produce alcohol, the strength of which is up to 95.6%.

The alcohol presented in the pharmacy is just such a product, but for some operations and reactions it is not enough, and you need to make an absolute one. There are several well-known methods, but they are all quite complex. You can bind the water included in the composition of alcohol, glycerin. Another option is chemical reactions with metals. Sometimes they resort to gypsum or potassium s alts. The reaction with quicklime has a certain efficiency. You can use calcium chloride. In practice, all these methods are rare, since it is difficult to implement them on an industrial scale, despite the good result of the interaction.

What to do?

From the above, it is clear why the price of absolute alcohol is high. To obtain this difficult product, it is necessary to use installations for azeotropic dehydration. The system requires the use of a high percentage of alcohol in water. The substance is mixed with benzene in liquid form, then the resulting compounds are distilled in columns designed for this. Several azeotropic techniques have been developed. The result of the process is a rather large volume of ethyl alcohol, the strength of which varies between 99.9-100%.

Although the price of absolute alcohol is high, the need to use this compound in a number of chemical processes causes considerable demand, so domestic and foreign enterprises produce quite large volumes of the absolute product. The finished liquid is included in fuel for space transport, used in cars and in the manufacture of a number of products used by ordinary people in everyday life. But in ordinary life, a person who is far from chemistry and production will hardly have to meet with absolute alcohol.

Nuances of obtaining

At present, ethyl alcohol is widely used in biology. This substance is necessary for the conservation of various drugs. Often biologists use the absolute form. At the same time, it is taken into account that conventional distillation cannot purify the product to the required level, since a boiling mixture is formed that cannot be separated when using a classical distillation unit. Temperatureboiling alcohol with a strength of 95.6% is 78.15 degrees Celsius, and for absolute this figure is 78.37 degrees.

It is noted that almost waterless alcohol for biological purposes is sometimes obtained by insisting rectified on copper sulfate powder for a long time - such a product is made by calcining copper sulphate. Thanks to s alt, water almost completely leaves the main mixture, while the powder does not dissolve in alcohol. If you take calcined lime and boil it in alcohol for several hours, the result of the reaction will be even better. The final stage of such a process is distillation, during which it is necessary to exclude interaction with air containing moisture.

Technical points

Ethanol is an odorless and colorless liquid. It has a pungent taste and a peculiar smell. Ethanol boils when heated to 78.4 on the Celsius scale, melts at -114.15 on the same measurement scale. The density of the substance is estimated at 0.794 t/m.

It will not be difficult to mix ethyl alcohol and water, glycerin and various other alcohols, some ethers and organic solvents. Substances can be mixed in any concentration and ratio. With certain substances, methylcarbinol forms an azeotropic mixture. This is observed when interacting not only with water, but also with chloroform. An azeotropic compound is generated if ethyl alcohol is mixed with ethyl acetate, benzene. Ethanol has the ability to form alcoholates if the substance interacts with magnesium, calcium s alts.

Alcohol: what happens?

It is customary to divide alcohol into food, technical. The definition of belonging to a category depends on what was used to obtain the liquid. Chemists responsible for the manufacture of the substance are well aware of the difference between distillate and rectified, the features of different categories. Rectified is a purer product, unlike distillate, which has a characteristic smell.

The possibilities of using alcohol are determined by its strength, the quality of rectification. Above, absolute alcohol was considered, which is necessary for technical purposes, but a rather curious topic is food. This liquid is made from plant products, food. To obtain ethyl alcohol, potatoes, some berries and fruits are used. You can use cereals. The cheapest option is alcohol derived from potatoes.

For industrial alcohol, you can take wood as a raw material. Sometimes it is obtained when working with oil transformation products. In the manufacture of technical alcohol, the feedstock is placed in a plant where hydrolysis takes place. In technical alcohol, impurities dangerous to human he alth are present in abundance. For this reason, it cannot be used in the food industry.

Features of the production process

Quality alcohol is obtained if the workflow proceeds using reliable raw materials, if the technology is followed and the distillation is performed in a quality manner, during which harmful compounds are removed. The degree of purification is the basis for classifying productsto a specific variety.

The higher the grade of alcohol, the less harmful compounds it contains. In addition, it shows his strength. Ethyl alcohol used in the food industry is obtained by diluting a rectified product that has undergone a highly efficient purification procedure. Softened water is used for dilution.