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Main application:
Maleic anhydride is an organic compound with the formula C2H2(CO)2O. It is the acid anhydride of maleic acid. It is a colorless or white solid with an acrid odor. It is produced industrially on a large scale for applications in coatings and polymers.
Maleic anhydride is produced by vapor-phase oxidation of n-butane. The overall process converts the methyl groups to carboxylate and dehydrogenates the backbone. The selectivity of the process reflects the robustness of maleic anhydride, with its conjugated double-bond system. Traditionally maleic anhydride was produced by the oxidation of benzene or other aromatic compounds. As of 2006, only a few smaller plants continue to use benzene.
In both cases, benzene and butane are fed into a stream of hot air, and the mixture is passed through a catalyst bed at high temperature. The ratio of air to hydrocarbon is controlled to prevent the mixture from igniting. Vanadium pentoxide and molybdenum trioxide are the catalysts used for the benzene route, whereas vanadium phosphate is used for the butane route:
C4H10 + 3.5 O2 → C4H2O3 + 4 H2O H = −1236 kJ/mol
The main competing process entails full combustion of the butane, a conversion that is twice as exothermic as the partial oxidation.
The traditional method using benzene became uneconomical due to the high and still rising benzene prices and by complying with the regulations of benzene emissions. In addition, in the production of maleic anhydride (4 C-atoms) a third of the original carbon atoms is lost as carbon dioxide when using benzene (6 carbon atoms). The modern catalytic processes start from a 4-carbon molecule and only attaches oxygen and removes water; the 4-C-base body of the molecule remains intact. Overall, the newer method is therefore more material efficient.
Physicochemical properties:
| Characteristics | Units | Guaranteed Values | Results |
| Appearance | White briquettes | White briquettes | |
| Purity(by MA) | WT% | 99.5 min | 99.71 |
| Molten Colour | APHA | 25 Max | 13 |
| Solidifying Point | ºC | 52.5 Min | 52.5 |
| Ash | WT% | 0.005 Max | <0.001 |
| Iron | PPM | 3 Max | 0.32 |
| Maleic Acid | WT% | ≤0.5 | 0.29 |
Around 50% of world maleic anhydride output is used in the manufacture of unsaturated polyester resins (UPR). Chopped glass fibers are added to UPR to produce fiberglass reinforced plastics that are used in a wide range of applications such as pleasure boats, bathroom fixtures, automobiles, tanks and pipes.
Maleic anhydride is hydrogenated used in the production of thermoplastic polyurethanes, elastane/Spandex fibers, polybutylene terephthalate (PBT) resins and many other products.
Diels-Alder reaction of maleic anhydride and butadiene and isoprene gives the respective tetrahydrophthalic anhydrides which can be hydrogenated to the corresponding hexahydrophthalic anhydrides. These species are used as curing agents in epoxy resins. Another market for maleic anhydride is lubricating oil additives, which are used in gasoline and diesel engine crankcase oils as dispersants and corrosion inhibitors. Changes in lubricant specifications and more efficient engines have had a negative effect on the demand for lubricating oil additives, giving flat growth prospects for maleic anhydride in this application.
A number of smaller applications for maleic anhydride. The food industry uses malic acid which is derivative of maleic anhydride in artificial sweeteners and flavour enhancements. Personal care products consuming maleic anhydride include hair sprays, adhesives and floor polishes. Maleic anhydride is also a precursor to compounds used for water treatment detergents, insecticides and fungicides, pharmaceuticals, and other copolymers.
Packaging and Shipping
25kg *1000 Bags, 25ton/FCL
Storage
Store in cool & dry place,Keep away from strong light and heat.
Q1: Can I get some samples?
A: Yes, we can supply free sample , but the shipping cost be paid by customers.
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