Q: What is Maleic Anhydride?

A: Maleic Anhydride (cis-butenedioic anhydride, toxilic anhydride, 2,5-dioxofuran) is an organic compound with the formula C2H2(CO)2O, and its molecular weight is 98.06 g/mol. And the vapor pressure for Maleic Anhydride is 0.1 to 0.2 mm Hg at 25 °C. It is the acid anhydride of maleic acid and in its pure state it is a colourless or white briquette or flake form crystal with pungent smell, which is inflammable and easily sublime. Maleic Anhydride powder is soluble in water to form maleic acid. And Maleic Anhydride was traditionally manufactured by the oxidation of benzene or other aromatic compounds. As of 2006, only a few smaller plants continue to use benzene; due to rising benzene prices, most Maleic Anhydride plants now use n-butane as a feedstock: 2 CH3CH2CH2CH3 + 7 O2 → 2 C2H2(CO)2O + 8 H2O.

Q: What is the chemical reactions of Maleic Anhydride?

A: The chemistry of Maleic Anhydride is very rich, reflecting its ready availability and bifunctional reactivity. It hydrolyzes, producing maleate , cis-HOOC–CH=CH–COOH. With alcohols, the half-ester is generated, e.g., cis-HOOC–CH=CH–COOCH3. Maleic Anhydride is a potent dienophile in Diels-Alder reactions. It is also a ligand for low-valent metal complexes, examples being Pt(PPh3)2(MA) and Fe(CO)4(MA). Maleic Anhydride dimerizes in a photochemical reaction to form cyclobutane tetracarboxylic dianhydride (CBTA). This compound is used in the production of polyimides and as an alignment film for liquid crystal displays.

Q: What are the conversion factors of Maleic Anhydride?

A: To convert concentrations in air (at 25 °C) from ppm to mg/m3: mg/m3 = (ppm) × (molecular weight of the compound)/(24.45). For Maleic Anhydride: 1 ppm = 4.0 mg/m3.

Q: What is the physical properties of Maleic Anhydride?

A: From single crystal x-ray diffraction data, Maleic Anhydride Flake is a nearly planar molecule with the ring oxygen atom lying 0.003 nm out of the molecular plane. A twofold rotation axis bisects the double bond and passes through the ring oxygen atom. Similar bond distances and angles for Maleic Anhydride 99.9% were obtained using electron diffraction and double resonance modulation microwave spectroscopic techniques. Values of the Raman polarizability were reported for single crystals of Maleic Anhydride. Density functional theory has been applied to Maleic Anhydride to give optimized geometry, harmonic vibrational frequencies, and electron affinity.

Q: What are the applications of Maleic Anhydride?

A: The unique nature of Maleic Anhydride’s chemical structure results in a highly reactive and versatile raw material. Its unsaturated double bond and acid anhydride group lend themselves to a variety of chemical reactions. Maleic Anhydride is an important organic synthetic raw material,Maleic Anhydride always used in the manufacture of plasticizer, plastic industry, paper-making industry,used to make paper treatment agent. And also can be used in modified rosin, unsaturated polyester resins, glass fibre reinforcement, coating, agricultural, surfactant, additive of plastics. Mixed with powders, such as calcium carbonate, the resin can be moulded to make synthetic marble, onyx and granite for wash basins, fire surrounds etc. Synthetic resin industry used in the manufacture of unsaturated polyester resin, alkyd resins; Coating industry used to make JueYuanQi, white porcelain, etc.;Pesticides used in the manufacture of pesticide marathon and high-efficiency, such as pesticide 4049; Medicine used to make long-term sulfonamides medicine; Oil industry for a fat oil preservative; The organic industry used to make fumarate and THF, r – butyl inner fat, 1.4 – butyl glycol, etc.

Q: Is Maleic Anhydride soluble?

A: In open air Maleic Anhydride easy to be sublimation. Into maleic acid which is rather corrosive. Maleic Anhydride dissolve in acetone, erher,ethyl acelate, etc. It will be deliquescence and creates malenic acid when wet. because of its feature, it shoud be stored in a cool, dry, well-ventilated area away from incompatible substances. It also should be store protected from moisture, and store protected from light.

Q: Is Maleic Anhydride combustible? How to deal with it?

A: Maleic Anhydride may be combustible at high temperature. The auto-ignition temperature is476.67°C (890°F), and the flash points is CLOSED CUP: 103.33°C (218°F).The flammable limits of Maleic Anhydride is LOWER: 1.4% UPPER: 7.1%. The products of combustion are carbon oxides (CO, CO2). Maleic Anhydride is combustible when exposed to heat or flame. Material in powder form, capable of creating a dust explosion. When heated to decomposition it emits acrid smoke and irritating fumes. If there is some small fire happened because of Maleic Anhydride, you can use dry chemical powder. If there is some large fire happened because of Maleic Anhydride, you can use water spray, fog or foam. Do not use water jet.

Q: How is Maleic Anhydride processed?

A: Pure butane and compressed air,are mixed and fed to an adiabatic reactor, where butane reacts with oxygen to form Maleic Anhydride. The reaction is exothermic, therefore, one could consider either a fluidized bed reactor or a packed bed reactor with heat removal to stay close to isothermal. The reactor effluent is cooled and sent to a packed bed absorber, where it is contacted with water to remove the light gases and all of the Maleic Anhydride reacts to form maleic acid. The vapor effluent, which consists of non-condensables must be sent to an after-burner to remove any carbon monoxide prior to venting to the atmosphere. The liquid effluent is then cooled and flashed at 101 kPa and 120°C in V-101. The vapor effluent from V-101 is sent to waste treatment. The liquid effluent is sent to R-102 where maleic acid is broken down to Maleic Anhydride and water. The reactor effluent is then sent to distillation column, T-102, where Maleic Anhydride and water are separated. The distillate is sent to waste treatment. The bottoms, consists of Maleic Anhydride 99%.

Industrial production of maleic acid should be in the vanadium pentoxide catalyst , at 450 ~ 500 ℃ with the air oxidation of benzene to produce Maleic Anhydride and then maleic acid is achieved by hydrolysis. Therefore, Maleic Anhydride is commonly used in industry instead of maleic acid.Maleic acid can generate succinic acid by catalytic hydrogenation or chemical reduction. And maleic acid can also generate meso- tartaric acid by potassium permanganate oxidation.

Q: What is the process technologies of Maleic Anhydride?

A: Maleic Anhydride is produced commercially by the oxidation of benzene or butane. The butane-based process is considered to have superior economics and is the preferred route by most producers. However, a small amount is produced by the benzene route. Although the butane-based process is considered to have superior economics and is the preferred route, Lonza claims its fixed bed benzene route is competitive in low cost revamps and medium-size plants. However, when the cost of benzene is high, this route is much less attractive.

Q: Does Maleic Anhydride has future prospects?

A: In 2008, approximately 51% of all Maleic Anhydride consumed was for the production of unsaturated polyester resins (UPR). 13% of 1,4-butanediol, Fumaric Acid for 4%, and lubricating oil additives for 3%. The remainder was consumed in miscellaneous uses, including copolymers, maleic acid, plasticizers, agricultural chemicals, alkenyl succinic anhydrides, alkyd resins, and a number of specialty chemicals and organic intermediates. There is little regional variation except for Maleic Anhydride consumed for butanediol. Unsaturated polyester resins will continue to have the largest market share and will drive refined Maleic Anhydride consumption on a global scale. The developing regions will experience the highest growth in Maleic Anhydride for UPR production since a considerable amount of UPR goes into infrastructure. Overall economic health will affect the UPR market as it is tied to the construction, automotive and marine industries. World Maleic Anhydride consumption has grown at around 3%/year over the long term. Growth will be slower in western Europe and the US but higher in eastern Europe, South America and Asia, in particular China. Growth will also reflect general economic conditions with many end-uses being in the construction, automobile and marine industries. Regionally, smaller end-use applications will experience higher-than-average growth, such as maleic copolymers in the United States. New product development—driven by increasing the use of renewables or replacing one petroleum-based chemical with a more environmentally friendly one—will drive Maleic Anhydride consumption in this application. The use of Maleic Anhydride copolymers will stand to gain from the increasing importance of recyclability, biodegradability and the use of more sustainable chemicals.

Q: Does Maleic Anhydride has hazard in daily life?

A: Maleic Anhydride may be spilled or emitted into the atmosphere from accidental during its manufacture, transport, or use. Exposure to Maleic Anhydride may occur releases to the environment or in workplaces, and would primarily be occupational from contact with spills, fugitive emissions, or vent gases. Acute (short-term) inhalation exposure of humans to Maleic Anhydride has been observed to cause irritation of the respiratory tract and eye irritation. Chronic (long-term) exposure to Maleic Anhydride has been observed to cause chronic bronchitis, asthma-like attacks, and upper respiratory tract and eye irritation in workers. In some people, allergies have developed so that lower concentrations can no longer be tolerated. Acute Effects: If there have a acute inhalation of Maleic Anhydride happened, the Maleic Anhydride has been observed to cause irritation of there spiratory tract, burning in the larynx, reflex cough, lacrimation, headaches, eye irritation, and corneal burns (that healed within 48 hours). Bronchial asthma was also observed in acute inhalation. Chronic Effects (Noncancer): Chronic exposure to Maleic Anhydride has been observed to cause chronic bronchitis, asthma-like attacks, pulmonary edema, upper respiratory tract irritation, eye irritation, and dermatitis in workers. In some people, allergies have developed so that lower concentrations can no longer be tolerated. People have made some experiment about chronic exposure of Maleic Anhydride, and the result is that rats will be have upper respiratory lesions, nasal discharge, dyspnea (shortness of breath), and sneezing by inhale Maleic Anhydride.

Q: What is the accidental release measures of Maleic Anhydride?

A: If there is some small spill happened, you should use appropriate tools to put the spilled solid in a convenient waste disposal container. If there is some large spill happened, espally some corrosive solid spill. You shoud try to stop leak if without risk. Do not get water inside container. Do not touch spilled material, you can use water spray to reduce vapors. You need prevent entry into sewers, basements or confined areas; dike if needed. Eliminate all ignition sources. Call for assistance on disposal. Be careful that the product is not present at a concentration level above TLV. Don’t forget to check TLV on the MSDS and with local authorities.

Q: How to take first aid measures?

A: If someone put Maleic Anhydride on eye, you should flush eyes with plenty of water for at least 15 minutes immediately. Then get immediate medical attention. If someone put Maleic Anhydride on skin, you should wash exposed skin with soap and water immediately. Remove contaminated clothing, including shoes, and thoroughly clean and dry before reuse. Get immediate medical attention if the condition is allowed. If someone inhale Maleic Anhydride carelessly, if adverse effects occur, you should remove him to uncontaminated area. Give artificial respiration if not breathing. Get immediate medical attention if the condition is allowed. If someone ingest Maleic Anhydride carelessly, if he had swallowed, let him drink plenty of water. Induce vomiting only at the instructions of a physician. Get immediate medical attention if the condition is allowed.

Q: What is the handling method of Maleic Anhydride?

A: First, you should keep container dry, keep Maleic Anhydride away from heat and sources of ignition. Empty containers pose a fire risk, evaporate the residue under a fume hood. Ground all equipment containing material. You must remember that do not ingest and do not breathe dust. Never add water to this product Wear suitable protective clothing In case of insufficient ventilation, wear suitable respiratory equipment. If ingested Maleic Anhydride, seek medical advice immediately and show the container or the label. Pay attention to avoid contact with skin and eyes, and keep Maleic Anhydride away from incompatibles such as oxidizing agents, reducing agents, acids, moisture.

Q: What is the storage method of Maleic Anhydride?

A: You should keep container dry, and keep Maleic Anhydride in a cool place. Ground all equipment containing material. Corrosive materials should be stored in a separate safety storage cabinet or room.Shelf life of Maleic Anhydride is one year.

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