Maleic anhydride, MALIEC ANHYDRIDE, MA, 108-31-6

Maleic anhydride, MALIEC ANHYDRIDE, MA, 108-31-6

CAS: 108-31-6

Molecular Formula: C4H2O3

Names and Identifiers

Physico-chemical Properties

Risk and Safety

Hazard Symbols	C - Corrosive
Risk Codes	R22 - Harmful if swallowed R34 - Causes burns R42/43 - May cause sensitization by inhalation and skin contact.
Safety Description	S22 - Do not breathe dust. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)
UN IDs	UN 2215 8/PG 3
WGK Germany	1
RTECS	ON3675000
FLUKA BRAND F CODES	21
TSCA	Yes
HS Code	2917 14 00
Hazard Class	8
Packing Group	III
Toxicity	LD50 orally in Rabbit: 1090 mg/kg LD50 dermal Rabbit 2620 mg/kg

Upstream Downstream Industry

Introduction

also known as maleic anhydride or anhydrous Apple anhydride, often abbreviated as maleic anhydride. Colorless crystal, a strong stimulus odor, freezing point of 52.8 ℃, boiling point of 202 ℃, easy sublimation. It is mainly prepared by oxidation of n-butane or butene in benzene or C4 fraction, and is a raw material for the production of unsaturated polyester and organic synthesis.

Production method

• The main production methods of maleic anhydride are benzene oxidation, butylene oxidation and n-butane oxidation, but the benzene oxidation is still the main method. 1. Benzene oxidation of benzene benzene is oxidized in a fixed bed under the action of a V-Mo-P catalyst to produce maleic anhydride at a reaction temperature of 365 ° C. (the reaction bed can also be used as a fluidized bed, but the consumption is high). Then the water is absorbed to produce maleic acid, and then the azeotropic dehydration and rectification are carried out to obtain the finished product. 2. Butane (or butene) oxidation butane (or butene) in the role of V-Mo catalyst, by air or oxygen oxidation to maleic anhydride, reaction temperature 350-400 ℃. It is then absorbed by water, dehydrated and refined to obtain a finished product.
• The synthesis method of maleic anhydride mainly includes benzene oxidation method, butene oxidation method, butane oxidation method, etc. At present, most of the benzene oxidation method is used in the production, that is, benzene is used as the raw material, and maleic anhydride is obtained by catalytic oxidation.
• a fixed-bed or ebullated-bed reactor was used to oxidize benzene to maleic anhydride with air under the action of a V-Mo-P catalyst at a reaction temperature of 365 °c. Then it is absorbed with water to form an aqueous solution of maleic acid, and then it is subjected to azeotropic distillation of xylene to obtain maleic anhydride. Finally, it is subjected to vacuum distillation to obtain a finished product.

Nature

colorless orthogonal needle crystal or white crystalline powder. Soluble in water, acetone, benzene, chloroform and other organic solvents. Solubility at 25 °c in the following solvents (GLOG): acetone 227, ethyl acetate 112, chloroform 52.5 1 benzene 50 1 toluene 23.4; O-xylene 19.4; Carbon tetrachloride 0.25; Petroleum ether. Soluble in alcohol to form ester. Dissolved in dioxane. Sublimated by heat. In case of high heat, open flame or contact with oxidant, there is a risk of combustion. Corrosive. Slowly hydrolyze in cold water to produce maleic acid. Contact with strong oxidants can cause combustion and explosion. If the temperature exceeds 66 ° C., the polymerization reaction may occur in contact with amines or alkali metals.

Preparation Method

malic acid reacts with acetyl chloride at a certain temperature. After the reaction, it is distilled and recrystallized from chloroform to obtain pure maleic anhydride.

Supplementary Information

category
Toxic grade poisoning
Acute oral toxicity-rat LD50: 708 mg/kg; Oral-mouse LD50: 2400 mg/kg
Skin irritation data-rabbit 500 mg/24 h mild; Eyes-rabbit 1%/2 min severe
Explosive hazard characteristics and explosive properties of air mixture
Flammable hazard characteristics flammable; Spicy and irritating smoke released from fire scene
Storage and Transportation characteristics the warehouse is ventilated and dried at low temperature; It is stored separately from the oxidant and amine
Extinguishing agent carbon dioxide, foam
Occupational Standard TWA 1 mg/m3; PEL 2 mg/m3

Use

A reagent having an organic compound having a conjugated double bond was measured. Also used in synthetic resin, paint, pesticide, medicine, food, and lubricating oil additives.

Stability

avoid exposure to moist air. Avoid contact with strong oxidizing agent, strong reducing agent, strong acid, strong alkali, alkali metal, water

• a colorless needle-like or plate-like crystal of orthorhombic crystal system. Dissolved in water to produce maleic acid. Dissolve in ethanol and produce esters.
• soluble in ethanol, ether and other organic solvents, difficult to dissolve in petroleum ether and carbon tetrachloride. The reaction with hot water produces maleic acid. It is easy for the olefin-based monomer to undergo copolymerization reaction; Homopolymerization may also be performed. It reacts with a glycol to form a linear unsaturated polyester and reacts with sulfur trioxide to form sulfonated maleic anhydride. Flammable. Toxic, splash and the skin should be washed with plenty of water. Production equipment should be sealed, and operators should wear protective equipment.

the product is toxic

Its toxicity is greater than that of the acid, which can stimulate the skin and mucous membranes. When the human body is exposed to high temperature liquid, its irritation is more serious, which can cause skin burning to injury, conjunctival and corneal redness, and even blindness in severe cases. LD50 for rats was
400 mg/kg. Mouse oral LD5060 ~ 465mg/kg. The maximum allowable concentration in air is 0.25*10-6. Rinse with plenty of water when splash and skin. Production equipment should be sealed, and operators should wear protective equipment.

present in smoke

strong irritation, causing burns, inhalation can cause pulmonary edema.

• is easily esterified. Acetic acid was evolved by heating to above 150 °c. The solution was heated to 100 °c where molecular chain scission occurred.

Safety

its dust and vapor are irritating. The staff should be protected and the working environment should be well ventilated. Should be stored separately from the oxidant, alkali. Store in a cool, ventilated warehouse. Keep away from fire and heat source. Protection from direct sunlight. The packaging must be sealed and free from moisture.

Scope of Application

The plastics industry is used to make plasticizers. The paper industry is used for the manufacture of paper treatment agents. Synthetic resins are industrially used in the manufacture of unsaturated polyester resins, alkyd resins, etc. The coating industry is used in the manufacture of insulating paint, white enamel, baking paint, varnish, etc. The pesticide industry is used for the manufacture of pesticide marathon and high efficiency and low toxicity pesticide 4049. The pharmaceutical industry is used in the manufacture of long-acting sulfonamides. The oil and fat industry is used as a preservative for fats and oils. The organic industry is used to produce fumaric acid and tetrahydrofuran. Used as a chemical reagent in analytical chemistry.

Precautions for use

Overview of risk

• health hazards: The product is irritating to dust and steam. After inhalation can cause pharyngitis, laryngitis and bronchitis. May be accompanied by Abdominal Pain. Direct contact between the eye and the skin has a significant irritating effect and causes burns. Chronic Effects: Chronic conjunctivitis, ulceration and inflammation of the nasal mucosa. It can cause skin rash and asthma.
• explosion hazard: the product is flammable, toxic, corrosive, irritating, can cause human burns, with sensitization.

first aid measures

• Skin Contact: remove contaminated clothing immediately and rinse with plenty of running water for at least 15 minutes. The patient visited hospital.
• eye contact: lift the eyelid immediately and rinse thoroughly with plenty of running water or normal saline for at least 15 minutes. The patient visited hospital.
• inhalation: rapid departure from the site to a place with fresh air. Keep airway unobstructed. Such as Dyspnea, to the delivery of oxygen. If breathing stops, perform artificial respiration immediately. The patient visited hospital.
• ingestion: gargle with water and drink milk or egg white. The patient visited hospital.

fire fighting measures

• hazard characteristics: powder and air can form an explosive mixture, and when it reaches a certain concentration, an explosion will occur on Mars.
• harmful combustion products: carbon monoxide, carbon dioxide.
• fire extinguishing method: fire-fighting personnel shall wear gas masks and full-body fire-fighting suits, and fire-fighting in the upward wind direction.
• fire extinguishing agent: water, foam, dry powder, carbon dioxide, sand.

emergency treatment of leakage

emergency treatment: Isolation leakage of contaminated area, restricted access. Cut off the fire source. Emergency personnel are advised to wear dust masks (full face mask) and acid and alkali protective work clothes. Collect in a dry, clean, capped container with a clean shovel and transfer to a safe place. If there is a large amount of leakage, it will be collected, recovered or transported to the waste disposal site for disposal.

handling and storage

• precautions for operation: closed operation, partial ventilation. Operators must be specially trained and strictly follow the operating procedures. It is recommended that operators wear self-priming filter dust masks, chemical safety glasses, rubber acid and alkali-resistant clothing and rubber acid and alkali-resistant gloves. Stay away from fire and heat source. No smoking is allowed in the workplace. The use of explosion-proof ventilation systems and equipment. Dust should be avoided. Avoid contact with oxidizing agents, reducing agents, acids. Handling should be light and light unloading, to prevent packaging and container damage. Fire fighting equipment and emergency treatment equipment for leakage shall be provided with corresponding varieties and quantities. Harmful substances may remain in the empty container.
• precautions for storage: Store in a cool, dry, well-ventilated warehouse. Keep away from fire and heat source. Keep the container sealed. It should be stored separately from oxidants, reductants, acids and edible chemicals, and mixed storage should not be avoided. With the corresponding varieties and quantity of fire fighting equipment. The storage area shall be provided with suitable materials for containment of the leakage. Shelf Life, 3 months from the date of delivery.

Reference Information