4-Methyl-2-pentanone

Description

4-Methyl-2-pentanone possesses a pleasant odor and can be prepared by the hydrogenation of mesityl oxide over a nickel catalyst at 160–190?°C, or alternatively by the oxidation of methyl isobutyl carbinol.

Chemical properties

4-Methyl-2-pentanone, commonly referred to as Methyl Isobutyl Ketone (MIBK), is a colorless liquid with a pleasant, sweet, fruity odor, possessing an odor threshold as low as 0.10 ppm. It exhibits a water solubility of 2% by weight and is miscible with various organic solvents. Its lower explosive limit is 1.2%, and the upper explosive limit reaches 8.0% at 200°F. MIBK may be incompatible with strong oxidizers and potassium tert-butoxide.

Occurrence

This compound is found in a wide range of natural products and foods, including fruit juices (orange, lemon, grape), vinegar, baked goods (wheat bread), dairy products (cheese, milk), meats (roast chicken, cooked beef, lamb fat, pork liver), seafood (crab, clam), alcoholic beverages (beer, brandy, plum brandy), drinks (coffee, tea), fruits and vegetables (papaya, ginger, baked potato, plum, mushroom, sesame, buckwheat), spices (hop oil, vanilla, sage), and fermented products (trassi, wort).

The Uses of 4-Methyl-2-pentanone

Methyl isobutyl ketone (MIBK, also known as 4-methyl-2-pentanone) is an organic solvent structurally and functionally similar to methyl butyl ketone. It is used not only as a solvent in paints, lacquers, and varnishes, but also in extraction processes and as a denaturant for rubbing alcohol. Additionally, it serves as a synthetic flavoring agent in certain rums, candies, and cheeses. Unlike methyl butyl ketone, MIBK does not occur naturally.

Production Methods

Methyl isobutyl ketone (MIBK) is primarily manufactured through two processes: the first is a mixed ketone method using isopropanol as a starting material to co-produce MIBK, diisobutyl ketone, and acetone in a single reaction; the second and dominant method involves a three-step reaction sequence generating diacetone alcohol and mesityl oxide as key intermediates en route to MIBK.

Reactivity Profile

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