Lignin

Lignin (English: Lignin) is the molecular structure of the amorphous, widely exist in plants contained oxygen generation or phenylpropanol derivative Structure unit Aromatic High polymer .
Lignin
Plant Xylem (a charge transport water and Mineral The structure) contains a lot of lignin, the xylem maintain high hardness to the extension of the whole plant weight.

Lignin The basic concept

Lignin by polymerization Aromatic alcohol A class of materials which exist in the woody tissue, the main role is to harden the cell wall formed by interweaving nets, as the main component of secondary wall.
 Lignin Lignin
Lignin in cellulose, compressive action. Lignin in woody plants, accounting for 25%, second of the world's most abundant organic (cellulose is first).

Lignin Monomer structure

 The molecular structure of lignin monomer The molecular structure of lignin monomer
Lignin by four alcohol monomer (p-coumaric alcohol, 5- hydroxy coniferol, Sinapyl alcohol ) a complex phenolic polymer formation.
Lignin is a plant cell wall One of the components, has the function of cells connected. Lignin is a polycyclic organic polymer containing many negative group, has a strong affinity for metal ions in soil.
Because of different monomers, lignin can be divided into 3 types: the syringyl propane structure monomer polymerization of purple Ding Xiangji (syringyl lignin, S- lignin lignin guaiacyl propane), by the structure of the monomer polymerization of guaiacyl lignin (guaiacyl, lignin, G- and wood quality) the p-hydroxyphenyl propane structure monomer polymerization of p-hydroxyphenyl lignin ( Para -hydroxy-phenyl lignin, H-); gymnosperm lignin is mainly guaiacyl lignin (G), dicotyledons containing guaiacyl syringyl lignin (G-S), monocotyledon is guaiacyl syringyl based - p-hydroxyphenyl lignin (G-S-H). From the point of view of Botany, lignin is surrounded on tracheid, catheter and fiber bundle cells and wood Thick walled cells Foreign substance, and that these cells have specific color reactions (plus Benzene three phenol A drop of solution, for a moment, then add a drop of hydrochloric acid were red), namely the chemical substances; from the point of view, lignin is composed of highly substituted phenyl propane unit randomly polymerized polymer, and cellulose, Hemicellulose Together, the formation of plants skeleton The main component in number after cellulose. Lignin filling in cellulose architecture enhanced the mechanical strength of the plant body to Conducting tissue The invasion of water transport and resistance to adverse environment.
The lignin in wood. Hard tissue In the content of more vegetables containing rare. Some seeds generally exists in soy, wheat bran, cocoa, strawberry and raspberry. The main component of bile is the most important function of the adsorption of bile acids, and exclusion of in vitro.
In addition, although the details are still can make nothing of it, but the lignin structure and polyphenol are very similar, therefore, lignin and polyphenol should have close relationship. In short, the two have very good effect on the body.

Lignin sustained development

Along with the understanding of human environmental pollution and resource crisis deepened, natural polymer is renewable and biodegradable properties has attracted more and more attention.
Kim was studied with JW coal liquefaction of papermaking of black liquor, they think that the formation of benzene lignin pyrolysis oxygen free radicals, and other radicals reaction at low temperature for coal pyrolysis has a very important role. These free radicals are efficient active intermediates, can make the coal of methylene fracture and promote the solution of coal.
Akash was studied with BA coal liquefaction of lignin dynamics. Use The state of Illinois Bituminous and corrosive lignin mixture, reaction in the initial hydrogen pressure of 1.1 MPa, 375 C and four hydrogen naphthalene as solvent under the. Coal liquefaction products and lignin mixture compared with alone with the product of coal liquefaction, containing less benzene insolubles. Study exclusion chromatography showed that the mixture of coal and lignin liquefaction products average molecular weight Lower than the molecules with single coal or single lignin liquefaction product quantity. The test data show that the transformation in adding lignin after coal rate increased by 22%, through the analysis of the mathematical model to describe the chemical reaction. Their impact on the liquid product cycles are studied. Preliminary tests show that with the increase of the product cycle of coal, the decomposition rate is reduced.
The above results indicate that, when the coal and liquefaction of lignin, can reduce the temperature of coal liquefaction. But researchers have different experimental results show that, compared with the coal liquefaction and coal. biomass Liquefied of liquefied products to improve the quality of liquid products, pentane soluble low molecular weight has been increased. These results may be the cause of formation of benzene lignin pyrolysis oxygen free radicals, and other radicals reaction at low temperature for coal pyrolysis has a very important role. When using the solvent molecules containing phenol liquefaction, coal conversion also increased significantly, although both at home and abroad on biomass and coal liquefaction has made some progress, but there are many in-depth, should focus on the study of coal and lignin liquefaction process conditions, modification of biomass and coal liquefaction test study, lignin and coal liquefaction dynamics, lignin for efficient catalyst and catalyst of coal.

Lignin Exhibition

The international carbon fiber conference held on ~26 July 25th in New York, Buffalo, the meeting by Harbert (Haper International) sponsored by the Oak Ridge National Laboratory (ORNL) Co. From more than and 20 countries more than 170 business representatives and participants. The meeting proposed the use of renewable raw materials for the production of low cost and high yield of carbon fiber is the development trend in the future.
2014 Chinese international industrial lignin and Application Exhibition will be held May 15, 2014 -17 at the Shanghai World Expo exhibition held.

Lignin Nature

Japan's eight Xi had lignin Bang under this definition: the role of acid in lignin is difficult to hydrolysis The high molecular weight substances mainly existed in woody plant cells, strengthen the plant tissue . his Chemical structure Is Phenylpropanes Structure unit The complex compounds, there are three kinds of basic structure (non condensed structure), namely guaiacyl syringyl structure, structure and structure of p-hydroxyphenol.

Lignin molecular structure

Also contains a variety of active functional groups such as hydroxyl, carboxyl, carbonyl, methyl and side chain structure. There are many hydroxyl groups in the lignin, with alcohol hydroxyl and phenolic hydroxyl in two forms, while the number of phenolic hydroxyl groups and directly affect the physical and chemical properties of wood, such as wood can reflect the degree of etherification and condensation of pigment, but also can measure the lignin solubility and reaction ability; on the side the lignin chain, a hydroxy benzoic acid, Vanillic acid There, syringic acid, hydroxy cinnamic acid, ferulic acid ester type structure, the ester type structure exists in the side chain of alpha or gamma position. In addition to the alpha position in the side chain ester type structure, and the ether type connection, or as a biphenyl structure of carbon carbon bond. The same as the hydroxyl side chain of lignin structure is directly related to its chemical reactivity.

Lignin The basic structure

Due to the existence of an aromatic, molecular structure of lignin in phenolic hydroxyl, Alcohol Carbon based conjugated double bonds and other active groups, it can be oxidation, reduction, hydrolysis, alcoholysis, acid induced oxygen radicals, carboxyl, photolysis, acylation, alkylation and sulfonation, halogenation, nitration, condensation or grafting many chemical reactions. Among them, the oxidation, acylation, condensation and sulfonation, graft copolymerization reaction properties of lignin application showed a particularly important role, but also an important way to expand its application. In this process, the sulfonation reaction is the basis and premise of application in the wood, so far, mostly in the application of lignin Lignosulfonate Form to be used. In the production of sulfite pulp In the process, it is because the original wood sulfite solution and wood powder in the prime sulfonation reaction, the introduction of sulfonic acid, increased the hydrophilicity, then the lignosulfonate in acidic liquor further hydrolysis reaction, the half fiber and lignin with the depolymerization of making wood the dissolution of lignosulfonates, the wood element, separation of cellulose and hemicellulose, the pulp, but also makes possible the application of wood.

Lignin application

Methods using lignin as rubber reinforcing agent, which belongs to the technical field of lignin in rubber industry application. The key point is in the papermaking wastewater concentrated added formaldehyde made from lignin formaldehyde resin, then proportionally adding sulfur, Zinc Oxide, stearic acid, curing agent, curing accelerator, rubber vulcanization activator and curing at a certain temperature. The invention can make the elements still do not need to add a lot of wood filler in rubber softener, which not only save a lot of rubber, vulcanized rubber and can obtain excellent properties, but not in the dusty sulfide pollution of the environment, and make the papermaking wastewater change harm into the great social and economic benefits.
The main use of wood sodium
The adhesion, dispersion, chelating are widely used in various industries, in order to improve its physical and chemical properties, save cost, improve efficiency.
1 reinforcing agent
In refractory material, ceramic products to reduce water, plasticizing and flocculation effect, can also be used in foundry industry, as an auxiliary binder, adhesive force and good disintegration.
2 powder binder
Ore smelting industry with mixed powder ball, after drying kiln, improving recovery rate, but also can be used as dressing agent.
3 used as concrete water reducer
In addition 0.2%-0.3%, can reduce the concrete mixing water consumption 10%-12%, reduce the water cement ratio, cement is reduced about 10%, improve the concrete workability and fluidity and anti permeability, improve the strength and density of concrete, with early strength effect, shorten the setting time, compressive strength improved, while reducing the concrete slump loss.
4 anti fouling and corrosion inhibitor
For industrial containers and pipelines, the anti fouling and corrosion effect, improve the service life of the pipeline and the window.
5 dispersant of coal water slurry
For the use of coal water slurry in thermal power plant and other enterprises, as dispersant, improve the dispersion ability of coal, increase coal-fired heating rate and utilization rate, greatly reduce the amount of coal contained in fly ash, while reducing bypass and caking, improve furnace life.
6 other
This product can be used as three oil chemicals, oil drilling mud thinner, and used to seal the well. In addition, can also be used for asphalt emulsifier, feed binder, refining agent, is also widely used in pesticide production, processing, coal leather filler, black soil, sand dunes, granulation and powder Jie control etc..

Lignin Related books

Edited by Jiang Tingda
ISBN:9787502530808
Publication date: 2001-3-1
Press: Chemical Industry Press
Market price: $20
High pure lignin extraction and thermoplastic modification
High pure lignin extraction and thermoplastic modification
[Abstract]
Lignin is a very rich source of thermoplastic natural polymer material, has the extremely broad utilization value. This book reflects the results of years of research in high pure lignin extraction and application fields, involving high pure lignin separation, extraction, modification, characterization and lignin thermoplastic materials, plastic materials, foam materials, lignin, lignin blend moisture agent application materials degradation etc..