什么是順酐？順酐又稱順丁烯二酸酐，馬來酸酐，2,5-呋喃二酮等。斜方晶系無色針狀或片狀晶體。有強烈刺激氣味，溶于乙醇、乙醚和丙酮，難溶于石油醚和四氯化碳。與熱水作用而成馬來酸。主要用于生產(chǎn)不飽和聚酯樹脂、醇酸樹脂、農(nóng)藥馬拉硫磷、低毒農(nóng)藥4049、長效碘胺的原料。

What is maleic anhydride? Maleic anhydride is also known as maleic anhydride, maleic anhydride, 2,5-furanedione, etc. Orthorhombic crystals are colorless needle-shaped or flaky crystals. It has a strong pungent smell and is soluble in ethanol, ether and acetone, but insoluble in petroleum ether and carbon tetrachloride. It reacts with hot water to form maleic acid. It is mainly used as raw material for the production of unsaturated polyester resin, alkyd resin, pesticide malathion, high-efficiency and low-toxicity pesticide 4049, and long-acting iodamine.

順酐的生產(chǎn)工藝：

Production process of maleic anhydride:

1、苯氧化法

1. Benzene oxidation method

苯氧化為順酐是在催化劑存在下進行的。常用催化劑的活性組分均為釩的氧化物（見金屬氧化物催化劑），為抑制苯被完全氧化，常加入鉬、磷、鈦、鎢、銀及堿金屬等元素的氧化物為添加劑，并采用低比表面的惰性物質(zhì)為催化劑載體，如α－氧化鋁、剛玉等。反應(yīng)在常壓下進行，溫度350～400℃。

The oxidation of benzene to maleic anhydride is carried out in the presence of catalyst. The active components of common catalysts are vanadium oxides (see metal oxide catalysts). In order to inhibit the complete oxidation of benzene, oxides of molybdenum, phosphorus, titanium, tungsten, silver and alkali metals are often added as additives, and inert substances with low specific surface are used as catalyst carriers, such as α－ Alumina, corundum, etc. The reaction is carried out under normal pressure at 350~400 ℃.

工藝過程由苯的氧化，順酐的分離和提純兩大部分組成。苯蒸氣和空氣能形成爆炸混合物，所以進入反應(yīng)器的混合氣中，苯的濃度應(yīng)在爆炸限之外，一般為1%～1.4%(摩爾)。

The process consists of oxidation of benzene, separation and purification of maleic anhydride. Benzene vapor and air can form explosive mixture, so the concentration of benzene in the mixed gas entering the reactor should be outside the explosion limit, generally 1%~1.4% (mol).

苯氧化為強放熱反應(yīng)，工業(yè)上常采用列管式固定床反應(yīng)器，有很大的傳熱面，管外為冷卻系統(tǒng)，反應(yīng)熱可用于產(chǎn)生高壓蒸汽。離開反應(yīng)器的氣體中含順酐約1%（摩爾）,用冷卻的辦法可將其中所含一半左右的順酐冷凝為液體，其余部分則用吸收法回收。

Benzene oxidation is a strong exothermic reaction. In industry, tubular fixed-bed reactors are often used, with large heat transfer surface. The outside of the tube is a cooling system, and the reaction heat can be used to generate high-pressure steam. The gas leaving the reactor contains about 1% (mol) of maleic anhydride. About half of the maleic anhydride can be condensed into liquid by cooling, and the rest can be recovered by absorption.

吸收劑用水或惰性有機溶劑，大多數(shù)工廠采用的是水。所得到的吸收液是順丁烯二酸的水溶液，濃度35%～40%(質(zhì)量)，需用共沸溶劑（例如二甲苯、苯甲醚）進行脫水，把酸重新轉(zhuǎn)化成酸酐。脫水也可在膜式蒸發(fā)器中進行。粗酐經(jīng)減壓精餾可得成品。以苯計算，整個過程的順酐收率為92%～96%（質(zhì)量）。

Absorbent water or inert organic solvent, most plants use water. The obtained absorption solution is an aqueous solution of maleic acid with a concentration of 35%~40% (mass). It needs to be dehydrated with azeotropic solvents (such as xylene and anisole) to convert the acid back into anhydride. Dehydration can also be carried out in membrane evaporator. Crude anhydride can be obtained by vacuum distillation. Based on benzene, the yield of maleic anhydride in the whole process is 92%~96% (mass).

2、C4烴氧化法

2. C4 hydrocarbon oxidation method

正丁烷與丁烯均含有與順酐相同的碳原子數(shù)，是生產(chǎn)順酐的理想原料。由于正丁烷較其他原料低廉，用正丁烷更為有利。其流程與苯氧化法基本相同，催化劑為釩-磷-氧體系，添加劑有鐵、鉛、鋅、銅、銻等元素的氧化物。

Both n-butane and butene contain the same carbon atoms as maleic anhydride, and are ideal raw materials for the production of maleic anhydride. Because the price of n-butane is lower than other raw materials, it is more advantageous to use n-butane. The process is basically the same as that of benzene oxidation. The catalyst is vanadium - phosphorus - oxygen system, and the additives are oxides of iron, lead, zinc, copper, antimony and other elements.

可用固定床反應(yīng)器或用流化床反應(yīng)器，反應(yīng)溫度約400℃。正丁烷-空氣混合物中正丁烷濃度為1.0%～1.6%(摩爾)。整個過程的順酐收率按正丁烷計約為50%。

Fixed bed reactor or fluidized bed reactor can be used, and the reaction temperature is about 400 ℃. The concentration of n-butane in the n-butane-air mixture is 1.0%~1.6% (mol). The yield of maleic anhydride in the whole process is about 50% based on n-butane.

由于C4烴氧化的選擇性較低,因此設(shè)備投資較以苯為原料時為高，且后加工不能采用部分冷凝，而必須將反應(yīng)氣體中的順酐全部用吸收法回收，從而使能耗加大。

Due to the low selectivity of C4 hydrocarbon oxidation, the equipment investment is higher than that when benzene is used as raw material, and partial condensation cannot be used for post-processing. Instead, all maleic anhydride in the reaction gas must be recovered by absorption method, thus increasing energy consumption.

順酐主要用于生產(chǎn)不飽和聚酯樹脂、醇酸樹脂、農(nóng)藥馬拉硫磷、低毒農(nóng)藥4049、長效碘胺的原料。也是涂料、馬來松香、聚馬來酐、順酐-苯乙烯共聚物的共聚單體，也是生產(chǎn)油墨助劑、造紙助劑、增塑劑、酒石酸、富馬酸、四氫呋喃等的有機化工原料。您有需求可以四十來我們完網(wǎng)站http://www.fahao168.com咨詢！

Maleic anhydride is mainly used as raw material for the production of unsaturated polyester resin, alkyd resin, pesticide malathion, high-efficiency and low-toxicity pesticide 4049, and long-acting iodamine. It is also a comonomer of paint, maleic rosin, polymaleic anhydride, maleic anhydride-styrene copolymer, and an organic chemical raw material for the production of ink additives, paper additives, plasticizers, tartaric acid, fumaric acid, tetrahydrofuran, etc. If you need, you can come to our website at forty http://www.fahao168.com consulting service