Этилацетоацетатом химические свойства, назначение, производство
Описание
The organic compound ethyl acetoacetate (EAA) is the ethyl ester of acetoacetic acid. It is mainly used as a chemical intermediate in the production of a wide variety of compounds, such as amino acids, analgesics, antibiotics, antimalarial agents, antipyrine and amino pyrine, and vitamin B1; as well as the manufacture of dyes, inks, lacquers, perfumes, plastics, and yellow paint pigments. Alone, it is used as a flavoring for food.
Химические свойства
Ethyl 3-Oxobutanoate is a colorless liquid with
a fruity, ethereal, sweet odor reminiscent of green apples. It is used to create fresh, fruity top notes in feminine fine fragrances. Ethyl acetoacetate occurs in flavors of
natural materials such as coffee, strawberries, and yellow passion fruits.
Вхождение
Naturally occurring in strawberry, coffee, sherry, passion fruit juice (yellow), babaco fruit (Carica pentagona
Heilborn) and bread.
Использование
Ethyl acetoacetate (EAA) is used as starting material for the syntheses of alpha-substituted acetoacetic esters and cyclic compounds, e.g. pyrazole, pyrimidine and coumarin derivatives as well as intermediate for vitamins and pharmaceuticals. Product Data Sheet
Подготовка
Ethyl acetoacetate is produced industrially by treatment of diketene with ethanol.
The preparation of ethyl acetoacetate is a classic laboratory procedure . It is prepared via the Claisen condensation of ethyl acetate. Two moles of ethyl acetate condense to form one mole each of ethyl acetoacetate and ethanol.
Методы производства
Ethyl acetoacetate is manufactured through a reaction of
high-purity ethyl acetate with sodium, followed by neutralization
with sulfuric acid.
Определение
This compound is a tautomer at room temperature
consisting of about 93% keto form and 7% enol
form.
Общее описание
A colorless liquid with a fruity odor. Flash point 185°F. Boiling point 365°F. May cause adverse health effects if ingested or inhaled. May irritate to skin, eyes and mucous membranes. Used in organic synthesis and in lacquers and paints.
Реакции воздуха и воды
Flammable.
Профиль реактивности
Ethyl acetoacetate, a beta-keto ester, is more reactive than many esters. Undergoes an exothermic cleavage reaction in the presence of concentrated base. Reacts with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Flammable hydrogen is generated by mixing esters with alkali metals and hydrides. Mixing with 2,2,2-tris(bromomethyl)ethanol and zinc led to an explosion [US Patent 3 578 619, Crotonaldehyde may rapidly polymerize with Ethyl acetoacetate (Soriano, D.S. et al. 1988. Journal of Chemical Education 65:637.).1971].
Опасность
Toxic by ingestion and inhalation; irritant
to skin and eyes.
Угроза здоровью
Liquid may cause mild irritation of eyes.
Химическая реактивность
Ethyl acetoacetate is subject to Keto - enol tautomerism. Ethyl acetoacetate is often used in the acetoacetic ester synthesis similar to diethyl malonate in the malonic ester synthesis or the Knoevenagel condensation. The protons alpha to carbonyl groups are acidic, and the resulting carbanion can undergo nucleophilic substitution. A subsequent thermal decarboxylation is also possible.Similar to the behavior of acetylacetone, the enolate of ethyl acetoacetate can also serve as a bidentate ligand. For example, it forms purple coordination complexes with iron (III) salts :
Ethyl acetoacetate can also be reduced to ethyl 3-hydroxy butyrate.
Профиль безопасности
eye irritant.
Combustible liquid when exposed to heat
or flame; can react with oxidzing materials.
Explosive reaction when heated with Zn +
tribromoneopentyl alcohol or 2,2,2
tris(bromomethy1)ethanol. To fight fire, use
alcohol foam, CO2, dry chemical. When
heated to decomposition it emits acrid
smoke and irritating fumes. See also
ESTERS.
Методы очистки
Shake the ester with small amounts of saturated aqueous NaHCO3 (until no further effervescence), then with water. Dry it with MgSO4 or CaCl2 and distil it under reduced pressure. [Beilstein 3 IV 1528.]
Этилацетоацетатом препаратная продукция и сырье
сырьё
препарат