Lignin - what is it? Lignin hydrolyzed. Application of hydrolytic lignin, properties

Lignin - what is it? Not everyone can answer this question, but we will try to understand. Lignin is a substance that is a part of absolutely all plants on Earth. In addition, it should be noted such useful components as cellulose and hemicellulose.

The main purpose of lignin - is to ensure the tightness of the walls of the vessels, through which water moves and the nutrients dissolved in it. Lignin and cellulose, being together in cell walls, increase their strength. Not all plants have the same amount of this compound. Most of it is contained in conifers, about 40%, but in deciduous species - only 25%.

Properties of lignin

This substance is a natural polymer of dark yellow color. It practically does not dissolve in water and organic solvents. Lignin - what is this in terms of structure? It is impossible to answer this question unambiguously, because, being in the composition of various plants, this substance can differ substantially in its structure.

During the decomposition of lignin, a nutrient-rich humus is formed, which plays an important role in nature. The processing of lignin in the natural environment is handled by an army of bacteria, fungi and some insects.

The main advantage of this substance is that it is not necessary to produce or extract it. Yes it is almost impossible, lignin is so firmly connected with plant cells that its artificial separation is a complex process.

That lignin, the production of which is carried out to date, is nothing more than ordinary waste in the processing of pulp. In this case, a large mass of it is lost, but the chemical activity increases.

Methods for isolating lignin

The process of extraction of this substance from wood is carried out for various purposes:

• Study of the properties of matter;
• Determination of the amount of lignin in various plants.

Methods for extracting the substance are selected depending on the purpose of its use. If the next task is to study, the methods of isolation should as little as possible affect the structure and quality of lignin. Although there are practically no such methods that would guarantee the receipt of the substance in an unchanged state.

After isolation, the lignin contains several impurities:

• Extractants in hydrolysis give insoluble compounds;
• Humification products of sugars;
• A mixture of hardly hydrolysable polysaccharides.

The most suitable conditions for isolating lignin are those in which the greatest amount of material is formed. In this case, lignin is obtained practically without impurities, and its small losses are observed.

The most common is the sulfuric acid method, but the hydrochloric acid is used much less often because of the inconvenience of working with concentrated acid.

Varieties of lignin

The main source of lignin production is the industrial production of cellulose. At different enterprises of this direction, different production technologies can be used, therefore, the lignin obtained in this case has different qualities and composition.

In the process of the production of alkalis or sulfates, sulfate lignin is obtained, in the production of acids, sulphite.

These species differ among themselves not only in composition, but also in the way of utilization. Sulphate lignin is incinerated, and the sulphite lignite is stored in special storage.

Hydrolysis enterprises produce hydrolysis lignin.

Properties of hydrolytic lignin

It is a powdered substance with a density of up to 1.45 g / cm³. Its color varies from light beige to various shades of brown. The content of lignin in such a substance can vary from 40 to 80%.

Hydrolytic lignin has toxic properties and a high ability for adsorption, on this basis its use in medicine is based.

If you spray a substance that becomes combustible in the dried form, then there may be a risk of explosion. Dry lignin generates a sufficiently large amount of heat during combustion. The temperature of its ignition is 195 degrees, and the smoldering begins already at a temperature of 185 ° C.

Production of lignin preparations

Lignin from wood is isolated in order to obtain then its preparations for various studies. Consider the stages of lignin release:

• Grinding of wood to the state of sawdust, and in some cases, flour;
• Treatment with an alcohol-toluene mixture for disposal of extractives;
• The use of acid catalysts, which prevent the transition of lignin to a soluble state.

In the production process, some of the soluble compounds are formed, which are precipitated, subjected to purification and dried, resulting in the formation of a powder.

The use of hydrolytic lignin

Despite the fact that this substance is difficult to process due to its complex nature and instability, it is possible to list the various industries where lignin is used. Application of the substance has the following directions:

• Production of fuel briquettes;
• As fuel oil;
• Production of reducing agents for certain metals and silicon;
• Filler in the production of plastics;
• Production of fuel gas;
• Manufacturing of fertilizers;
• Production of herbicides;
• As a raw material for the production of phenol, acetic acid;
• Production of activated carbon;
• As a sorbent for cleaning urban and industrial wastewater;
• Production of medical products;
• Production of bricks and ceramic products.

The reasons for the increased demand for lignin

Lignin hydrolyzed is an excellent fuel, which when burned gives a lot of energy. In addition, raw materials for the production of such an energy resource are quite affordable and renewable.

Not only in our country, but also around the world at present the issue of producing alternative energy sources is topical. There are a number of reasons for this, among which you can list the following:

1. Natural energy carriers - coal, oil and gas require various costly methods for their extraction. This can not but affect the ever-growing cost.
2. The energy sources that are currently used relate to exhaustible natural resources, so there will come a time when their reserves will almost be spent.
3. The production of alternative energy sources is stimulated by the state in many countries.

Lignin as fuel

Today, lignin is increasingly used as an alternative fuel. What is it and what does it look like?

The substance is sawdust with a moisture content of up to 70%, which differ in their composition depending on the raw materials. Their structure is very similar to charcoal, which also has a large number of tiny pores. The properties of such a substance make it possible to subject it to briquetting and granulation. If high pressure is applied to such a briquette, it becomes a viscous plastic mass.

Granules made from such lignin have high heat transfer, but do not produce much smoke. Fuel briquettes and pellets are a quality material, with the combustion of which a lot of heat is released, and soot practically does not. Hence, we can conclude that lignin serves as an excellent raw material for the production of fuel in briquettes.

Use of lignin in the powder state

This substance in the powder state finds its application as an additive in the production of asphalt concrete. The use of hydrolytic lignin allows:

• Increase strength, water resistance and resistance to cracking;
• Save road construction materials;
• Significantly improve the ecological situation in the places where the waste is stored;
• To restore fertility to those lands that are used for dumps.

In the road industry, it is advantageous to use lignin. Its properties are such that it allows a tangible increase in the quality of the building material. In addition, lignin makes it possible to replace expensive additives.

Lignin derivatives

Derivatives of this substance are lignosulfonates, which are formed during the sulphite process of wood processing. Lignosulfonates have a high activity, which allows them to find their application in various industries:

• Oil industry (regulate the properties of drilling fluids) ;
• Foundry production (act as a binding material in mixtures);
• Production of concrete;
• Building industry (as emulsifiers in road emulsions);
• Raw material for the production of vanillin;
• Agriculture (tillage to prevent erosion).

Sulfate lignin has a high density and chemical resistance. In dry condition it is a brown powder that dissolves in ammonia, alkalis, ethylene glycol, dioxin.

Sulfate lignin has no toxicity, is not sprayed and is not dangerous from the standpoint of fire hazard. It is used:

• As a plasticizer in the production of ceramic products, concrete;
• As a raw material for the production of plastics and phenol-formaldehyde resins;
• As a link in the manufacture of cardboard, wood and paper plates;
• As an additive in the production of rubber and latex.

Now it becomes clear how lignin is widely used. What it is, now no one has any questions, because thanks to its qualities this substance is very in demand in the modern world.

Medicines based on lignin

As we have already explained, the use of hydrolytic lignin is possible in the medical field. It is possible to list the following preparations on its basis:

• "Lignosorb" is prescribed for diseases of the digestive tract, food poisoning;
• "Polifan" has the same recommendations for use;
• "Polyphepan" brings relief from diarrhea and dysbiosis;
• "Filtrum-STI";
• "Entegnin."

Application of "Polyphepan"

Another name for this drug is hydrolysis lignin. It is produced in the form of granules, suspensions, powders and tablets. The preparation of vegetable origin, it is based on lignin. Instructions for use say that such a medicine is able to bind microorganisms well, as well as products of their vital activity.

In addition, under the action of the drug neutralize toxic substances of various types: heavy metals, radioactive isotopes, ammonia. Lignin hydrolyzed detoxifies the body, and also has antioxidant and hypolipidemic action.

That's what an extensive list of merits has lignin! The instruction also says that taking this drug, you can compensate for the lack of dietary fiber in the intestines, which take an active part in the digestion process, normalize the microflora and increase immunity.

Indications for the reception of "Polyphepan" are:

• Chronic or acute diseases of the digestive tract;
• Food poisoning;
• diarrhea;
• Viral hepatitis;
• cholera;
• Intestinal dysbiosis;
• Salmonellosis;
• Colitis;
• Allergic manifestations;
• Violation of the metabolism of fats in the body;
• Recovery period after chemotherapy or radiation;
• Gynecological problems: candidiasis, vaginosis.

A fairly extensive list of indications has a preparation such as lignin. The instruction also notes some contraindications:

• Hypersensitivity to the drug;
• Chronic constipation;
• gastritis;
• diabetes.

In the process of taking lignin, there may be side effects: an allergic reaction or constipation.

The methods of using the drug and its dosage are determined by the doctor depending on the diagnosis and complexity of the condition. It is usually prescribed to take lignin for a week, but with some problems, the duration of therapy can be increased to a month.

Ecology and lignin

This substance is formed in large quantities during the processing of cellulose. It is put in large dumps, which contribute to environmental pollution. In addition, cases of spontaneous combustion of lignin are not uncommon.

To date, the issue of using the substance as a fuel is acute, since after its combustion a large amount of waste is generated, which harms nature. Lignin finds its application in many industries, therefore, first of all it is important to solve the issue of ecological safety of the environment.