Эфир диэтиловый

Описание

Diethyl ether is a component of starting fluids and is used as a solvent in the manufacture of synthetic dyes and plastics. Because of its characteristics, diethyl ether was widely used in many countries as an anesthetic agent, but was then replaced by other substances in the 1960s.

Химические свойства

Ether, (C2H5)2,also known as ethyl ether, is a colorless liquid. It is used as a solvent,a denaturant, and as an anesthetic in medicine. lt is an organic compound in which two hydrocarbon radicals are joined by an atom of oxygen.

Физические свойства

Colorless, hygroscopic, volatile liquid with a sweet, pungent odor. Odor threshold concentration is 330 ppb (quoted, Keith and Walters, 1992).

История

Ether was supposedly discovered by Raymundus Lullus (1232–1315) around 1275, although there is no extant evidence of this in his writings. The discoverer of ether is often credited to the German physician and botanist Valerius Cordus (1515–1554), who gave the first description of the preparation of ether in the mid-16th century. Cordus called the substance oleum vitrioli dulce, which is translated as sweet oil of vitriol. Cordus used sulfuric acid (oil of vitriol) to catalyze the conversion of alcohol to ether. At approximately the same time Paracelsus (1493–1541), a Swiss physician who is also cited as a discoverer of ether, observed that chickens were safely put to sleep by breathing vapors from sweet oil of vitriol. In 1730, August Siegmund Frobenius changed the name of sweet vitriol to ether.

Использование

Diethyl ether has been used extensively as a general anesthetic.

Методы производства

Ether is produced by the dehydration of ethanol using sulfuric acid: 2CH₃CH₂OH +2H₂SO₄ → (CH₃CH₂)₂O + H₂SO₄ + H₂O.the temperature of the reaction is carriedout at about 140°C to control for unwanted products.the volatile ether is distilled from themixture. Ether can also be prepared by Williamson synthesis. In this reaction, ethanol reactswith sodium to form sodium ethanolate (Na+C₂H₅O?). Sodium ethanolate then reacts withchloroethane to form ether and sodium chloride: Na+C₂H₅O? +C₂H₅Cl → C₂H₅OC₂H₅ +NaCl. Ether is also produced as a by-product in the production of ethanol.

Определение

diethyl ether: A colourless flammablevolatile ether, C2H5OC2H5; r.d. 0.71;m.p. –116°C; b.p. 34.5°C. It can bemade by Williamson’s synthesis. Itis an anaesthetic and useful organicsolvent.

Общее описание

A clear colorless liquid with an anesthetic odor. Flash point -49°F. Less dense than water and slightly soluble in water. Hence floats on water. Vapors are heavier than air. Used as a solvent and to make other chemicals.

Реакции воздуха и воды

Highly flammable. Oxidizes readily in air to form unstable peroxides that may explode spontaneously [Bretherick, 1979 p.151-154, 164]. A mixture of liquid air and Diethyl ether exploded spontaneously, [MCA Case History 616(1960)].

Профиль реактивности

Occasional explosions have occurred when aluminum hydride was stored in ether. The explosions have been blamed on the presence of carbon dioxide impurity in the ether, [J. Amer. Chem. Soc. 70:877(1948)]. Diethyl ether and chromium trioxide react violently at room temperature. Solid acetyl peroxide in contact with ether or any volatile solvent may explode violently. A 5-gram portion in ether detonated while being carried, [Chem. Eng. News 27:175(1949)]. Nitrosyl perchlorate ignites and explodes with Diethyl ether. A mixture of ether and ozone forms aldehyde and acetic acid and a heavy liquid, ethyl peroxide, an explosive, [Mellor 1:911(1946-1947)].

Опасность

CNS depressant by inhalation and skin absorption. Very flammable, severe fire and explosion hazard when exposed to heat or flame. Forms explosive peroxides. Explosive limits in air 1.85– 48%.

Угроза здоровью

The acute toxicity of diethyl ether is low. Inhalation of high concentrations can cause sedation, unconsciousness, and respiratory paralysis. These effects are usually reversible upon cessation of exposure. Diethyl ether is mildly irritating to the eyes and skin, but does not generally cause irreversible damage. Repeated contact can cause dryness and cracking of the skin due to removal of skin oils. The liquid is not readily absorbed through the skin, in part because of its high volatility. Diethyl ether is slightly toxic by ingestion. Diethyl ether is regarded as having adequate warning properties. There is no evidence for carcinogenicity of diethyl ether, and no reproductive effects have been reported. Chronic exposure to diethyl ether vapor may lead to loss of appetite, exhaustion, drowsiness, dizziness, and other central nervous system effects.

Пожароопасность

Diethyl ether is extremely flammable (NFPA rating = 4) and is one of the most dangerous fire hazards commonly encountered in the laboratory, owing to its volatility and extremely low ignition temperature. Ether vapor may be ignited by hot surfaces such as hot plates and static electricity discharges, and since the vapor is heavier than air, it may travel a considerable distance to an ignition source and flash back. Ether vapor forms explosive mixtures with air at concentrations of 1.9 to 36% (by volume). Carbon dioxide or dry chemical extinguishers should be used for ether fires. Diethyl ether forms unstable peroxides on exposure to air in a reaction that is promoted by light; the presence of these peroxides may lead to explosive residues upon distillation.

Воспламеняемость и взрывоопасность

Diethyl ether is extremely flammable (NFPA rating = 4) and is one of the most dangerous fire hazards commonly encountered in the laboratory, owing to its volatility and extremely low ignition temperature. Ether vapor may be ignited by hot surfaces such as hot plates and static electricity discharges, and since the vapor is heavier than air, it may travel a considerable distance to an ignition source and flash back. Ether vapor forms explosive mixtures with air at concentrations of 1.9 to 36% (by volume). Carbon dioxide or dry chemical extinguishers should be used for ether fires. Diethyl ether forms unstable peroxides on exposure to air in a reaction that is promoted by light; the presence of these peroxides may lead to explosive residues upon distillation.

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.

Промышленное использование

Diethyl ether as a commercial product is available in several grades and is used as an extraction solvent, reaction solvent, and as a general anesthetic. Ethyl ether is an excellent solvent for alkaloids, dyes, fats, gums, oils, resins, and waxes. Blends of ethyl ether and ethanol are excellent solvents for cellulose nitrate used in the manufacture of guncotton, in collodion solutions and pyroxylin plastics. Ethyl ether is used in the recovery of acetic acid from aqueous solutions in the cellulose acetate and plastic industry. It is used as a starter fuel for diesel engines and as a denaturant in denatured ethanol formulations. Grignard and Wurtz-Fillig synthesis reactions use diethyl ether as an anhydrous, inert reaction medium.

Возможный контакт

Ethyl ether is used as a solvent for waxes, fats, oils, perfumes, alkaloids, dyes, gums, resins, nitrocellulose, hydrocarbons, raw rubber, and smokeless powder. It is also used as an inhalation anesthetic; a refrigerant; in diesel fuels; in dry cleaning; as an extractant; and as a chemical reagent for various organic reactions

Экологическая судьба

Photolytic. The rate constant for the reaction of ethyl ether and OH radicals in the atmosphere at 300 K is 5.4 x 10^-12 cm³/molecule?sec (Hendry and Kenley, 1979).
Chemical/Physical. The atmospheric oxidation of ethyl ether by OH radicals in the presence of nitric oxide yielded ethyl formate as the major product. Minor products included formaldehyde and nitrogen dioxide. In the absence of nitric oxide, the products were ethyl formate and acetaldehyde (Wallington and Japar, 1991).
Ethyl ether will not hydrolyze (Kollig, 1993).

хранилище

ether should be used only in areas free of ignition sources (including hot plates, incandescent light bulbs, and steam baths), and this substance should be stored in tightly sealed metal containers in areas separate from oxidizers. Because of the tendency of diethyl ether to form peroxides on contact with air, containers should be dated upon receipt and at the time they are opened. Diethyl ether is generally supplied with additives that inhibit peroxide formation; distillation removes these inhibitors and renders the liquid more prone to peroxide formation. Material found to contain peroxides should be treated to destroy the peroxides before use or disposed of properly.

Перевозки

UN1155 Diethyl ether or Ethyl ether, Hazard Class: 3; Labels: 3-Flammable liquid

Несовместимости

May form explosive mixture with air. Incompatible with strong acids; strong oxidizers halogens, sulfur, sulfur compounds, causing fire and explosion hazard. Can form peroxides from air, heat, sunlight; may explode when container is unstoppered or otherwise opened. Attacks some plastics, rubber and coatings. Being a nonconductor, chemical may accumulate static electric charges that may result in ignition of vapor.

Утилизация отходов

Concentrated waste containing no peroxides-discharge liquid at a controlled rate near a pilot flame. Concentrated waste containing peroxidesperforation of a container of the waste from a safe distance followed by open burning. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal