Maleic anhydride is referred to as maleic anhydride, also known as 2, 5-furandione, translated as maleic anhydride or anhydrous maleic anhydride, at room temperature is colorless aciculate crystal, with pungent odor and sour taste, flammable, sublimed, easily soluble in water, maleic acid (maleic acid), also soluble in benzene and acetone, ethanol and other organic solvents, is a commonly used important organic chemical raw materials.
Maleic anhydride, as one of the three major organic anhydrides (acetic anhydride, maleic anhydride, phthalic anhydride), is a widely used basic organic chemical raw material, with a production history of more than 70 years. Maleic anhydride contains conjugated cisyl groups, in which one vinyl group is connected to two carbonyl groups, so its chemical properties are very active, and it is easy to generate many downstream products through photochemical reaction, addition reaction, amidation reaction, esterification reaction, sulfonation reaction, hydration reaction, oxidation reaction, reduction reaction, hydrogenation reaction, etc. Widely used in the production of unsaturated polyester resin, paint, paint, ink, engineering plastics, medicine, pesticides, food, feed, oil additives, paper, textile and other industries.
Chemicals produced with maleic anhydride as raw materials such as succinic anhydride, γ-butanolactone, 1, 4-butanediol, tetrahydrofuran, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, L-aspartate, alanine and secondary derivatives of these products such as PTMEG, PBT are currently widely used and popular chemical raw materials in the domestic market. The main downstream uses of maleic anhydride are as follows:
(1) Unsaturated polyester resin
Unsaturated polyester resin (UPR) is a kind of unsaturated linear polyester polymer, which is prepared by polycondensation and dehydration of maleic anhydride and diols, and then adding crosslinking agent styrene. The appearance is transparent, light yellow or brown viscous liquid, with excellent physical and mechanical properties and corrosion resistance, can be cured under normal temperature and pressure conditions, simple processing technology, has become one of the main products of thermosetting resin, in industry, agriculture, transportation, construction, arts and crafts and many other industries have a wide range of uses.
The main uses of UPR can be roughly divided into two categories of enhanced (FRP) and non-enhanced, of which FRP (commonly known as glass fiber reinforced plastic) is mainly used in the following areas:
A. Construction: mobile houses, corrugated tiles, doors and Windows, downspouts, high water tanks, cool water towers, ventilation pipes, complete sets of sanitary bathing sets, building decoration materials, etc.
B, automobile, ship manufacturing: auto parts, bumpers, vehicle and ship shell, small and medium-sized ship hull, spare parts, etc.
C, anti-corrosion pipes, tanks, containers, etc.
D, new energy: wind turbine fan, bracket, solar water heater frame, support parts, etc.
E, entertainment, sports: water slides, yachts, bumper cars, motor boats, sports windsurfing, sailing, golf clubs, clubs, softball bats, bowling, ice hockey poles, pole vaulting poles, parallel bars, uneven bars, fishing gear, etc.
China in the above enhanced products, building materials products have broad prospects, automotive, shipbuilding applications are still few, and pipeline, container products have been exported in bulk to the United States and Southeast Asian countries, other areas are yet to be developed.
Non-enhanced UPR products are roughly: buttons (has basically replaced polymethacrylate methyl grease, commonly known as plexigma), craft jewelry, children's toys, furniture, artificial agate, artificial marble, artificial granite, polaroid board paint, automotive putty (polyester putty), polymer concrete, etc., of which craft jewelry and children's toys export huge.
(2) 1, 4-butanediol, tetrahydrofuran and other maleic anhydride hydrogenation products
1, 4-butanediol (BDO) is an important basic raw material of fine chemical industry, which has strong vitality in the series of maleic anhydride deep processing products, and its application is constantly expanding. BDO is widely used, and its derivatives are fine chemical products with high added value, widely used in solvent, medicine, cosmetics, plasticizer, curing agent, pesticide, rust remover, foam artificial leather, fiber, engineering plastics and other fields.
(3) Fumaric acid
Fumaric acid and maleic anhydride also have conjugated cisyl, chemical properties are very active, can be widely used in paint, resin, medicine, plasticizer, food additives (used in the production of beverages, jelly, fruit, fruit, meat, vegetables, etc. As a sour agent and preservative). Forage grade fumaric acid and its derivative dimethyl fumarate can be used as acidic preservative, which can improve the taste and utilization efficiency of feed. Industrial grade fumaric acid is used as raw material for the production of unsaturated polyester resin (UPR) and alkyd resin and electrophoretic paint. L-aspartate produced from fumaric acid is an important component in amino acid infusion for medicine.
(4) Paint, paint
The paint industry is an important user of maleic anhydride, but maleic anhydride in the paint and paint industry is more used in the film forming substances of synthetic paint (that is, surface coatings such as piano, bar, furniture surface decoration layer, etc., suitable for the substrate of wood, metal or resin, protection and decorative effect is outstanding), the product varieties are water-based paint, oil-based paint and synthetic resin paint, etc. Such as alkyd resin paint, epoxy resin paint, phenolic resin paint, polyester paint, natural resin paint, maleic anhydride rosin and tung oil maleic anhydride resin, etc., a wide variety of categories.
(5) Agricultural chemicals
Maleic anhydride is the raw material of several important insecticides, herbicides and plant growth regulators. China is the largest agricultural country in the world in terms of total grain output, and its application in agricultural insecticides, herbicides and plant growth regulators has a very broad future.
(6) succinic acid
Succinic acid (succinic acid) is mainly used in coatings, dyes, adhesives and medicine. The alkyd resin produced from succinic acid has good flexure, elasticity and water resistance. The diphenyl ester of succinic acid is an oil intermediate, which reacts with aminoanthraquinone to produce anthraquinone dye. Succinic acid can be used in the pharmaceutical industry to produce sulfanilamide, vitamin A, vitamin B and hemostatic drugs. Succinic acid is also widely used in the paper and textile industries, as a raw material for lubricants, photographic chemicals and surfactants.
