АКРОЛЕИН

Описание

The first time that acrolein was produced as a commercial product was in the 1930s through the vapor-phase condensation of acetaldehyde and formaldehyde. Another method was developed in the 1940s, which involved the vapor-phase oxidation of propylene. In the 1960s, some advances were found in propylene oxidation process by the introduction of bismuth molybdate-based catalysis, and that became the primary method used for the commercial production of acrolein. Some bioproducts formed for this reaction are acrylic acid, carbon oxides, acetaldehyde, acetic acid, formaldehyde, and polyacrolein. In World War I, it was used as a chemical weapon (pulmonary irritant and lachrymatory agent). Commercial acrolein contains 95.5% or more of the compound, the main impurities being water (<3.0% by weight) and other carbonyl compounds (<1.5% by weight), mainly propanol and acetone. Hydroquinone is added as an inhibitor of polymerization (0.1–0.25% by weight).

Химические свойства

Acrolein is a highly flammable, clear to yellowish liquid. It has a piercing, disagreeable odor and causes tears.

Физические свойства

Colorless to yellow, clear, watery liquid imparting a very sharp, acrid, pungent, or irritating odor. Odor threshold concentrations reported were 0.11 mg/kg by Guadagni et al. (1963), 0.21 ppm_v by Leonardos et al. (1969), and 36 ppb_v by Nagata and Takeuchi (1990). In addition, Katz and Talbert (1930) reported an experimental detection odor threshold concentration of 4.1 mg/m³ (1.8 ppm_v).

Использование

Acrolein is used in the synthesis of acrylic acid. manufacture of colloidal forms of metals; making plastics, perfumes; warning agent in methyl chloride refrigerant. Has been used in military poison gas mixtures. Used in organic syntheses. Aquatic herbicide.

Определение

A colorless liquid unsaturated aldehyde with a pungent odor. It can be polymerized to make acrylate resins.

Реакции воздуха и воды

Highly flammable. A dangerous fire risk [Hawley]. Water soluble. Reacts slowly and exothermically with water to give 3-hydroxypropionaldehyde. A hazard can develop from this reaction if acrolein is stored over a layer of water.

Профиль реактивности

ACROLEIN, [INHIBITED] can react violently with oxidizing agents. Polymerizes exothermically on contact with small amounts of acids (including sulfur dioxide), alkalis, volatile amines and pyridines, salts, thiourea, oxidizing agents (air) and on exposure to light and heat. Polymerization initiated by amines and pyridines occurs after a deceptive induction period. Water solutions of mineral acids and metal ions can initiate polymerization. The inhibitor (usually hydroquinone) greatly reduces tendency to polymerize. Undergoes Diels-Alder reaction with itself to give acrolein dimer. This can become a runaway reaction at 90°C [Kirk-Othmer, 4th Ed, Vol. 1]. Mixing in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: 2-aminoethanol, ammonium hydroxide, chlorosulfonic acid, ethylenediamine, ethyleneimine [NFPA 1991].

Пожароопасность

Under fire conditions, polymerization may occur. If inside a container, violent rupture of the container may take place. When heated to decomposition, Acrolein emits highly toxic fumes. Alkalis or strong acids act as catalysts, causing a condensation reaction and liberating energy. Reaction may be very rapid and violent. Readily converted by oxygen to hazardous peroxides and acids. Unstable, avoid exposure to alkalis, strong acids, oxygen, elevated temperatures, such as fire conditions. (Polymerization inside container could cause violent rupture of container under fire conditions.)

Воспламеняемость и взрывоопасность

Acrolein is a highly flammable liquid (NFPA rating = 3) and its vapor can travel a considerable distance and "flash back." Acrolein vapor forms explosive mixtures with air at concentrations of 2.8 to 31% (by volume). Carbon dioxide or dry chemical extinguishers should be used for acrolein fires.

Профиль безопасности

Human poison by inhalation and intradermal routes. Poison experimentally by most routes. Human systemic irritant and pulmonary system effects by inhalation include: lachrymation, delayed hypersensitivity with multiple organ involvement, and respiratory system damage. Severe eye and skin irritant. Experimental reproductive effects. Human mutation data reported. Questionable carcinogen. Dangerous fire hazard when exposed to heat, flame, or oxidizers. An explosion hazard. Incompatible with amines, SO2, metal salts, oxidants, (light + heat). Violent polymerization reaction on contact with strong acid, strong base, weak acid conditions (e.g., nitrous fumes, sulfur dioxide, carbon dioxide), thiourea, or dimethylamine. When heated to decomposition it emits highly toxic fumes; can react vigorously with oxidizing materials. To fight fire, use CO2, dry chemical, or alcohol foam,

Возможный контакт

Used as pharmaceutical; slimicide; and in production of cosmetics and food supplements; as an intermediate in the production of glycerine and in the production of methionine analogs (poultry feed protein supplements). It is also used in chemical synthesis (1,3,6-hexametriol and glutaraldehyde); as a liquid fuel; antimicrobial agent, in algae and aquatic weed control; and as a slimicide in paper manufacture; making plastics, drugs, and tear gas. Also, most allyl compounds may be metabolized to allyl alcohol which is metabolized to acrolein.

Канцерогенность

Acrolein is a reactive intermediate of the commonly used chemotherapeutic drugs cyclophosphamide and ifosphamide. Acrolein-modified DNA was found in human peripheral blood lymphocytes from cancer patients previously treated with cyclophosphamide (a chemotherapeutic), but no association was found for cyclophosphamine. Acrolein has a classification of C, possible human carcinogen, based on limited animal carcinogenicity data and paucity of human evidence for this effect.

Метаболический путь

When fish are exposed to 14C-acrolein, the metabolites are identified from the edible tissues and there is very little similarity in the metabolism of acrolein among the test species. The most notable observation is that acrolein is never detected in any tissues sampled, and glycidol, glycerol, 1,3- propanediol, and glyceric acid are the major metabolites found in catfish, crayfish, bluegill, and clams, respectively.

хранилище

Work with acrolein should be conducted in a fume hood to prevent exposure by inhalation, and splash goggles and butyl rubber gloves should be worn at all times to prevent eye and skin contact. Acrolein should be used only in areas free of ignition sources. Containers of acrolein should be stored in secondary containers in areas separate from amines, oxidizers, acids, and bases.

Перевозки

Acrolein, stabilized, Hazard class: 6.1; Labels: 6.1-Poison Inhalation Hazard, 3-Flammable liquids. Inhalation Hazard Zone A.

Методы очистки

Purify acrolein by fractional distillation, under nitrogen, drying with anhydrous CaSO4 and then distilling under vacuum. Blacet, Young and Roof [J Am Chem Soc 59 608 1937] distilled it under nitrogen through a 90cm column packed with glass rings. To avoid formation of diacryl, the vapour is passed through an ice-cooled condenser into a receiver cooled in an ice-salt mixture and containing 0.5g catechol. The acrolein is then distilled twice from anhydrous CuSO4 at low pressure, catechol being placed in the distilling flask and the receiver to avoid polymerization. [Alternatively, hydroquinone (1% of the final solution) can be used.] [Beilstein 1 IV 3435.]

Несовместимости

May form explosive mixture with air. Elevated temperatures or sunlight may cause explosive polymerization. A strong reducing agent; reacts violently 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. Polymerizes exothermically on contact with small amounts of acids (including sulfur dioxide), alkalis, volatile amines and pyridines, salts, thiourea, oxidizing agents (air) and on exposure to light, and heat. Polymerization initiated by amines and pyridines occurs after a deceptive induction period. Water solutions of mineral acids and metal ions can initiate polymerization. The inhibitor (usually hydroquinone) greatly reduces tendency to polymerize. Reacts with acids, alkalis, ammonia, amines, oxygenperoxides. Shock-sensitive peroxides or acids may be formed over time. Attacks zinc and cadmium

Утилизация отходов

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. Incineration. Conditions are 816 C, 0.5 second minimum for primary combustion; 1093 C, 1.0 second for secondary combustion.