2-бутанон

Описание

2-Butanone is a stable, highly flammable chemical. It is incompatible with oxidising agents, bases, and strong reducing agents. It is a colourless liquid with a sharp, sweet odour. 2-Butanone is produced in large quantities. It is used as a solvent and nearly half of its use is in paints and other coatings because it will quickly evaporate into the air and it dissolves many substances. It is also used in glues and as a cleaning agent.

Химические свойства

Methyl ethyl ketone (MEK) is a colorless liquid with an odor that has been described as moderately sharp, fragrant, peppermint, or acetone like. It soluble in water up to 28% by weight and is miscible with many other organic solvents. The lower explosive limit is 1.4% and the upper explosive limit is 11.4%. Methyl ethyl ketone may be incompatible with strong oxidizers, amines, ammonia, inorganic acids, caustics, isocyanates, and pyridines. When used industrially, methyl ethyl ketone must be handled with caution, as it is a Class lB flammable liquid NIOSH (2010).

Физические свойства

2-Butanone is a clear, colorless, volatile, very flammable liquid with a sweet, mint or acetone-like odor. Odor threshold concentration is 10.0 ppmv (Leonardos et al., 1969). Experimentally determined detection and recognition odor threshold concentrations were 5.8 mg/m3 (2.0 ppmv) and 16 mg/m3 (5.4 ppmv), respectively (Hellman and Small, 1974). It is incompatible with oxidizing agents, bases, and strong reducing agents. It is a colorless liquid with a sharp, sweet odor. 2-Butanone is produced in large quantities. It is used as a solvent and nearly half of its use is in paints and other coatings because it quickly evaporates into the air and it dissolves many substances. It is also used in glues and as a cleaning agent.

Вхождение

Reported found as an impurity among products from the dry distillation of wood and in the oil (extracted with ether) of black tea; it is also present in coffee, cheese, bread, some citrus oils and some other natural products (grape, raspberry).

Использование

2-Butanone is an eye irritant that has been used as a water soluble photoinitiator for the photopolymerization of methacrylic acid (MAA). As solvent; in the surface coating industry; manufacture of smokeless powder; colorless synthetic resins.

Подготовка

By catalytic dehydrogenation of secondary butyl alcohol; by dehydration of butane-2,3-diol by refluxing with 25% aqueous H2SO4. Industrially, it is also prepared by controlled oxidation of butane, by dry distillation of calcium acetate and calcium propionate, or by refluxing methyl acetoacetate and diluted H2SO4.

Методы производства

Methyl ethyl ketone is commercially manufactured from nbutene in a metal-catalyzed hydrogenation reaction that proceeds through the intermediate formation of 2-butanol . A second method of synthesis involves the liquid- phase oxidation of n-butane with the formation of acetic acid as a coproduct.

Определение

ChEBI: A dialkyl ketone that is a four-carbon ketone carrying a single keto- group at position C-2.

Общее описание

Methyl ethyl ketone (MEK) is a colourless liquid with a sweet and sharp odour. It is soluble in alcohol, ether, acetone benzene, and water. It is a solvent often found in mixtures with acetone, ethyl acetate, n-hexane, toluene, or alcohols. It has applications in the surface coating industry and in the de-waxing of lubricating oils. MEK is used in the manufacture of colourless synthetic resins, artificial leather, rubbers, lacquers, varnishes, and glues.

Реакции воздуха и воды

Highly flammable. Slightly soluble in water.

Опасность

Flammable, dangerous fire risk. Toxic by ingestion.

Угроза здоровью

Occupational workers are exposed to 2-butanone by breathing contaminated air in workplaces associated with the production or use of paints, glues, coatings, or cleaning agents. Prolonged exposures to 2-butanone cause symptoms of poisoning such as cough, dizziness, drowsiness, headache, nausea, vomiting, dermatitis, irritation of the nose, throat, skin, and eyes and at very high levels cause drooping eyelids, uncoordinated muscle movements, loss of consciousness, and birth defects. Chronic inhalation studies in animals have reported slight neurological, liver, kidney, and respiratory effects. However, information on the chronic (long-term) effects of 2-butanone (methyl ethyl ketone) in humans is limited.

Пожароопасность

Flammable/combustible material. May be ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.

Воспламеняемость и взрывоопасность

Methyl ethyl ketone is extremely flammable (NFPA rating = 3), and its vapor can travel a considerable distance to an ignition source and "flash back." MEK vapor forms explosive mixtures with air at concentrations of 1.9 to 11% (by volume). Carbon dioxide or dry chemical extinguishers should be used for MEK fires.

Химическая реактивность

Reactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.

Возможный контакт

MEK is used as a solvent in nitrocellulose coating and vinyl film manufacture; in smokeless powder manufacture; in cements and adhesives and in the dewaxing of lubricating oils. It is also an intermediate in drug manufacture

Канцерогенность

Although MEK has not been specifically examined in a rodent 2-year bioassay, there is little to suggest that the material is carcinogenic. When used as a delivery vehicle in a dermal carcinogenicity bioassay for organic sulfur compounds, Horton et al. found that the application of benzyl disulfide or phenylbenzylthiophene in a 25–29% solution of MEK in dodecylbenzene together failed to increase the incidence of benign skin papillomas in male C3H/HeJmice. The mice used in the experiments were treated twice a week for 52 weeks with the MEKcontaining test solution.

хранилище

2-Butanone should be protected from moisture.

Перевозки

UN1193 Methyl ethyl ketone or Ethyl methyl ketone, Hazard Class: 3; Labels: 3-Flammable liquid.

Несовместимости

May form explosive mixture with air. Violent reaction with strong oxidizers, amines, ammonia, inorganic acids; caustics, isocyanates, pyridines. Incompatible with potassium tert-butoxide, 2-propanol, chlorosulfonic acid; oleum. Attacks some plastics. Ketones are incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, nitrated amines, azo, diazo, azido compounds, carbamates, organic cyanates

Утилизация отходов

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal. Incineration

Меры предосторожности

2-Butanone vapor and air mixtures are explosive. It reacts violently with strong oxidants and inorganic acids causing fi re and explosion hazard.