4-Метил-2-пентанона

Описание

4-Methyl-2-pentanone has a pleasant odor. May be prepared by hydrogenation of mesityl oxide over Ni at 160 - 190°C; also by oxidation of methyl isobutyl carbinol.

Химические свойства

4-Methyl-2-pentanone has a fruity, ethereal, spicy (on dilution) odor.

Физические свойства

Clear, colorless, watery liquid with a mild, pleasant odor. Odor threshold concentration is 47 ppb_v (Leonardos et al., 1969). Experimentally determined detection and recognition odor threshold concentrations were 400 μg/m³ (100 ppb_v) and 1.1 mg/m³ (270 ppb_v), respectively (Hellman and Small, 1974).

Вхождение

Reported found in orange and lemon juice, grape; vinegar, baked potato, papaya, ginger, wheat bread, cheeses, milk, cooked egg, roast chicken, cooked beef, lamb fat, pork liver, hop oil, beer, cognac, coffee, tea, plumcot, plum brandy, mushroom, trassi, sesame seed, buckwheat, wort, elder flower, Bourbon vanilla, clary and red sage, crab, clam and Chinese quince.

Использование

Methyl isobutyl ketone (hexone, isobutyl methyl ketone, 4-methyl-2-pentanone) is an organic solvent similar in structure and use to methyl butyl ketone. In addition to its use as a solvent for paints, lacquers, and varnishes, methyl isobutyl ketone is used in extraction processes and as a denaturant for rubbing alcohol. Methyl isobutyl ketone is also used as a synthetic flavoring in some varieties of rum, candy, and cheese. Unlike methyl butyl ketone, methyl isobutyl ketone has not been found to occur naturally.

Методы производства

Methyl isobutyl ketone can be manufactured by two processes . The first is a mixed ketone process where MiBK, diisobutyl ketone, and acetone are coproduced in a single reaction using isopropanol as a starting material. The second method is used to produce the majority of MiBK and involves a three-step reaction sequence in which diacetone alcohol and mesityl oxide are formed as intermediates.

Подготовка

By hydrogenation of mesityl oxide over Ni at 160 to 190°C; also by oxidation of methyl isobutyl carbinol.

Общее описание

A clear colorless liquid with a pleasant odor. Flash point 73°F. Less dense than water. Vapors heavier than air.

Реакции воздуха и воды

Highly flammable. 4-Methyl-2-pentanone is sensitive to air (may form explosive peroxides). Slightly soluble in water.

Профиль реактивности

4-Methyl-2-pentanone is incompatible with caustic soda and other strong alkalis, hydrochloric acid, sulfuric acid and other strong inorganic acids, amines and oxidizing agents such as hydrogen peroxide, nitric acid, perchloric acid and chromium trioxide. 4-Methyl-2-pentanone reacts violently with potassium tert-butoxide. 4-Methyl-2-pentanone reacts vigorously with reducing materials. .

Опасность

Flammable, dangerous fire risk, explosivelimits in air 1.4–7.5%. Avoid ingestion and inhala-tion. Upper respiratory tract irritant, dizziness, andheadache. Possible carcinogen.

Угроза здоровью

Vapor causes irritation of eyes and nose; high concentrations cause anesthesia and depression. Liquid dries out skin and may cause dermatitis; irritates eyes but does not injure them.

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

MIBK is used as a solvent; a denaturant; and as an extractant; in the manufacture of methyl amyl alcohol; as a solvent in paints, varnishes, and lacquers; as an alcohol denaturant; as a solvent in uranium extraction from fission products.

Канцерогенность

The National Toxicology Program conducted cancer bioassays by exposing groups of 50 male and 50 female F344 rats and B6C3F1 mice to MiBK vapor at 0, 450, 900, or 1800 ppm 6h/day, 5 days/ week for 2 years. Survival and body weight gain were decreased in male rats at 1800 ppm. Body weight gain was also decreased in male rats at 900 and in female mice at 1800ppm. A higher incidence of mineralization of the renal papilla was observed in male rats at all MiBK exposure levels. Chronic progressive nephropathy (CPN) and the incidences of adenoma and adenoma or carcinoma (combined) were increased for the male 1800 ppm exposure group. The severity of CPN and renal tubular hyperplasia was increased in all male rat exposure groups. An uncertain increase in mononuclear cell leukemia, adrenal medulla hyperplasia, and a positive trend for increases in benign or malignant pheochromocytomas (combined) were reported for the 1800 ppm male group. The NTP considered that there was some evidence of carcinogenic activity in male rats based on increased incidences of renal tubule neoplasms.
None of the rodent bioassay results were considered clear evidence of carcinogenicity by NTP.

Перевозки

UN1245 Methyl isobutyl ketone, Hazard Class: 3; Labels: 3-Flammable liquid.

Методы очистки

Reflux the ketone with a little KMnO4, wash it with aqueous NaHCO3, dry with CaSO4 and distil it. Acidic impurities are removed by passage through a small column of activated alumina. [Beilstein 1 IV 3305.]

Несовместимости

Able to form unstable and explosive peroxides on contact with air. Reacts violently with strong oxidizers, potassium tert-butoxide; strong acids; aliphatic amines; reducing agents

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.