Mesityl oxide

Description

The commercial grade of 4-methyl-3-penten-2-one exhibits an unpleasant odor. The pure material has a pleasant honey-like odor. This substance may be prepared by reacting acetone or diacetone alcohol with iodine or other dehydrating agent; by condensation of acetone over sulfonated polystyrene-divinylbenzene resin used as an ion exchange catalyst.

Chemical properties

Mesityl oxide is a clear, pale yellow, or colorless liquid with a strong peppermint odor. The odor threshold is 0.05 ppm.

Physical properties

Clear, pale yellow liquid with a strong, peppermint, or honey-like odor. Experimentally determined detection and recognition odor threshold concentrations were 70 μg/m³ (17 ppb_v) and 200 μg/m³ (50 ppb_v), respectively (Hellman and Small, 1974).

Occurrence

Reported found in orange juice, baked potato, bell pepper, sauerkraut, tomato, crisp bread, parmesan cheese, milk, chicken fat, hop oil, rum, coffee, tea, peanut, passion fruit, mushroom, tamarind, prickly pear, buckwheat, basil, elder flower, rosemary, shrimp, nectarine, clam and maté

The Uses of Mesityl oxide

Mesityl oxide is used as a solvent for resins,gums, nitrocellulose, oils, lacquers, and inks;as an insect repellant; and in ore flotation..

The Uses of Mesityl oxide

Solvent for nitrocellulose, many gums and resins, particularly vinyl resins. In lacquers, varnishes and enamels. In making methyl isobutyl ketone.

Preparation

4-Methyl-4-penten-2-one is the precursor of methyl isobutyl ketone (see Section 2.2) and can be produced from acetone in a single- or a two-step process . Pure mesityl oxide is obtained by azeotropic distillation of the crude watercontaining product. Subsequent purification by removal of the accompanying impurities, such as mesitylene and phorone [504-20-1], is effected by distillation.

Definition

ChEBI: 4-Methyl-3-penten-2-one, 9CI is an olefinic compound. It is functionally related to an acrylic acid.

Synthesis Reference(s)

Tetrahedron Letters, 27, p. 3733, 1986 DOI: 10.1016/S0040-4039(00)83866-6

General Description

Mesityl oxide appears as a colorless, oily liquid with a pungent honey-like odor. Flash point 87 °F. Less dense than water and slightly soluble in water. Vapors heavier than air. Used in paint removers, as a solvent for plastics, and as an insect repellent.

Air & Water Reactions

Highly flammable. Slightly soluble in water

Reactivity Profile

Mixing MESITYL OXIDE in equal molar proportions with any of the following substances in a closed container caused the temperature and pressure to increase: 2-aminoethanol, chlorosulfonic acid, ethylene diamine, nitric acid, oleum, or sulfuric acid [NFPA 1991].

Hazard

Flammable, moderate fire risk. Toxic by ingestion, inhalation, and skin absorption. Eye and upper respiratory tract irritant, central nervous system impairment.

Health Hazard

Inhalation causes irritation of nose and throat, headache, dizziness, difficult breathing. Contact with liquid or concentrated vapor causes severe eye irritation. Liquid irritates skin. Ingestion causes irritation of mouth and stomach.

Health Hazard

Mesityl oxide is a moderately toxic substance, more toxic than the saturated ketones.Inhalation of its vapors can cause irritationto the eyes, skin, and mucous membranes. Inhumans, the irritation effect on the eyes andnose are reported to be 25 and 50 ppm. Athigh concentrations narcosis can result. Otherthan narcosis, prolonged exposure to highconcentrations can injure the lungs, liver, and kidney. A concentration of 2500 ppm waslethal to rats.
LD50 value, oral (rats): 1120 mg/kg.

Fire Hazard

Behavior in Fire: Vapor is heavier than air and may travel a considerable distance to a source of ignition and flash back.

Safety Profile

Poison by intraperitoneal route. Moderately toxic by ingestion. Mildly toxic by inhalation and skin contact. Human systemic effects by inhalation: conjunctiva irritation. This compound is highly irritating to all tissues on contact; its vapors also are irritating. High concentrations are narcotic. It is readdy absorbed through intact skin. Single exposures tend to indicate that ths ketone has greater acute and narcotic action than isophorone. It can have harmful effects upon the hdneys and liver, and may damage the eyes and lungs to a serious degree. Prolonged exposure can injure liver, kidneys, and lungs. It can cause opaque cornea, keratoconus, and extensive necrosis of cornea. Dangerous fire hazard when exposed to heat, sparks, or flame; can react with oxidzing materials. Reacts violently with 2-amino ethanol, chlorosulfonic acid, ethylene diamine, HNO3, oleum, H2SO4. An insect repellent. To fight fire, use alcohol foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. See also KETONES.

Potential Exposure

Mesityl oxide is used as a solvent for cellulose esters and ethers and other resins in lacquers and inks. It is used in paint and varnish removers and as an insect repellent

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seekmedical attention immediately. If this chemical contactsthe skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove fromexposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.

storage

Color Code—Red: Flammability Hazard: Store in a flammable liquid storage area or approved cabinet away from ignition sources and corrosive and reactive materials. Mesityl oxide 1715 Prior to working with this chemical you should be trained on its proper handling and storage. Before entering confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. Store in tightly closed containers in a cool, well-ventilated area away from oxidizers, strong acids. See incompatibilities above. Where possible, automatically pump liquid from drums or other storage containers to process containers.

Shipping

UN1229 Mesitly oxide, Hazard Class: 3; Labels: 3-Flammable liquid.

Purification Methods

Purify it by distillation, preferably in a vacuum or via the semicarbazone (m 165o) which is decomposed to pure ketone. The 2,4-dinitrophenylhydrazone (m 205-206o) crystallises from EtOH. [Johnson J Am Chem Soc 73 5888 1951, Johnson J Am Chem Soc 75 2720 1953, Erskine & Waight J Chem Soc 3425 1960, Beilstein 1 H 736, 1 I 382, 1 II 793, 1 III 2995, 1 IV 3471.]

Incompatibilities

May form explosive mixture with air. May be able to form explosive peroxides. May react violently with nitric acid; aliphatic amines; alkanolamines, 2- aminoethanol, ethylene diamine; chlorosulfonic acid; oleum (fuming sulfuric acid). Not compatible with oxidizers, strong acids; strong bases; reducing agents; halogens. Dissolves some forms of plastics, resins and rubber. Attacks copper.

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.