Maleic anhydride, also known as maleic anhydride (MAH), is an anhydride of maleic acid. It is a colorless or white solid with a sour taste at room temperature, and its molecular formula is C4H2O3. Maleic anhydride was previously prepared by catalytic oxidation of benzene, but due to price reasons, the purpose of maleic anhydride is:

1、用作生产1,4-丁二醇、四氢呋喃、琥珀酸、不饱和聚酯树脂、醇酸树脂等的原料，也用于医药和农药。

1. Used as raw materials for the production of 1,4-butanediol, tetrahydrofuran, succinic acid, unsaturated polyester resin, alkyd resin, etc., as well as in pharmaceuticals and pesticides.

2、金属选矿中充当捕收剂。

2. Act as a collector in metal beneficiation.

3、用于合成，也用作合成纤维中间体。

3. Used for synthesis and also as an intermediate for synthetic fibers.

4、顺酐是一种重要的不饱和有酸酐的酐基本原料，在农药生产上用于合成磷杀虫药的中间体顺丁烯二酸二乙酯、哒嗪硫磷的中间体1-苯基-3，6-二羟基哒嗪，以及拟除虫菊酯杀虫药胺菊酯、克菌丹的中间体。此外，还用于生产不饱和聚酯树脂、油墨助剂、造纸助剂、涂料以及医药工业、食品工业等。

4. Maleic anhydride is an important unsaturated anhydride basic raw material used in the synthesis of phosphorus insecticides in pesticide production, including diethyl maleate, 1-phenyl-3,6-dihydroxypyridazine, as an intermediate of pyridazinon, and intermediate of pyrethroid insecticides such as fenpropathrin and chloramphenicol. In addition, it is also used in the production of unsaturated polyester resin, ink additives, paper additives, coatings, as well as the pharmaceutical and food industries.

5、主要用于生产不饱和聚酯树脂、醇酸树脂、长效碘胺的原料。也是涂料、马来松香、聚马来酐、顺酐-苯乙烯共聚物。也是生产油墨助剂、造纸助剂、增塑剂和酒石酸、富马酸、四氢呋喃等的化工原料。

5. Mainly used as raw materials for the production of unsaturated polyester resin, alkyd resin, and long-acting iodine amine. It is also a coating, maleic rosin, polymaleic anhydride, and maleic anhydride styrene copolymer. It is also a chemical raw material for producing ink additives, papermaking additives, plasticizers, and tartaric acid, fumaric acid, tetrahydrofuran, etc.

6、顺酐是一种常用的重要基本化工原料。其下游产品有着相当广泛的开发和应用前景。主要用于合成不饱和聚酯树酯，它是制造汽车部件、船舶、耐腐蚀性化工设备和日用品的原料。顺酐也是生产润滑油的添加剂、涂料、农药、富马酸、共聚物、食品添加剂等重要中间体。

6. Maleic anhydride is a commonly used and important basic chemical raw material. Its downstream products have a wide range of development and application prospects. Mainly used for synthesizing unsaturated polyester resin, it is a raw material for manufacturing automotive components, ships, corrosion-resistant chemical equipment, and daily necessities. Maleic anhydride is also an important intermediate in the production of lubricants, coatings, pesticides, fumaric acid, copolymers, food additives, and other additives.

顺酐的合成方法：

Synthesis method of maleic anhydride:

1、苯氧化法。

1. Benzene oxidation method.

苯蒸气和空气在以V2O5-MnO3等为活性组分，α-Al2O3为载体的催化剂上发生气相氧化反应生成顺酐。苯氧化法是生产顺酐的传统生产方法，工艺技术成熟可靠。

Benzene vapor and air are active components such as V2O5-MnO3, α- Gas phase oxidation reaction occurs on the catalyst supported by Al2O3 to generate maleic anhydride. The benzene oxidation method is a traditional production method for maleic anhydride, with mature and reliable process technology.

2、C4烯烃法。

2. C4 olefin method.

该法是以混合C4馏分中的有效成分正丁烯、丁二烯等为原料，和空气(或氧气)，在V2O5-P2O5系催化剂作用下经气相氧化反应生成顺酐，其中正丁烯在反应过程中先脱氢生成丁二烯，再氧化生成顺酐。在反应过程中，除生成主产物外，还副产生成一氧化碳、二氧化碳和水以及少量的乙醛、乙酸和呋喃等，原料单耗高，收率低，该法已经逐渐被淘汰。

This method uses the active components such as n-butene and butadiene in the mixed C4 fraction as raw materials, and air (or oxygen), to undergo gas-phase oxidation reaction under the action of V2O5-P2O5 catalyst to generate maleic anhydride. n-butene is first dehydrogenated to produce butadiene during the reaction process, and then oxidized to produce maleic anhydride. In the reaction process, in addition to generating the main product, there are also by-products such as carbon monoxide, carbon dioxide, and water, as well as a small amount of acetaldehyde, acetic acid, and furan. The raw material consumption is high, and the yield is low. This method has gradually been phased out.

3、苯酐副产法。

3. Phthalic anhydride by-product method.

在生产苯酐时，可以副产得到一定数量的顺酐产品，其产量约为苯酐产量的5%。在苯酐生产中，反应尾气经洗涤塔除去物后排放到大气中，洗涤液为顺酐和少量的苯甲酸、苯二甲酸等杂质，经浓缩精制和加热脱水后得到顺酐产品。

When producing phthalic anhydride, a certain amount of maleic anhydride products can be obtained as a byproduct, with a yield of approximately 5% of the phthalic anhydride production. In the production of phthalic anhydride, the reaction tail gas is discharged into the atmosphere after being removed by a washing tower. The washing solution consists of maleic anhydride and a small amount of impurities such as benzoic acid and phthalic acid. After concentration, refinement, and heating dehydration, the product of maleic anhydride is obtained.

4、正丁烷氧化法。

4. N-butane oxidation method.

正丁烷氧化工艺是以正丁烷为原料，在V2O5-P2O5系催化剂作用下发生气相氧化反应生成顺酐。该工艺自实现工

The n-butane oxidation process takes n-butane as the raw material and undergoes a gas-phase oxidation reaction to produce maleic anhydride under the action of V2O5-P2O5 catalyst. This process is self actualized