Description
Mesity oxide(141-79-7) is a tri-functional intermediate of considerable utility in the synthesis of a number of different types of organic compounds, such as mesityl oxide can be hydrogenated to methyl isobutyl ketone and other flavor ingredients in foods, such as 4- methyl-pentanone. Mesityl oxide can be used as a solvent for resins, gums, nitrocellulose, oils, lacquers, and inks. It is also used as an insect repellant and used in ore flotation.
References
[1] Pradyot Patnaik, A Comprehensive Guide to the Hazardous Properties of Chemical Substances, 3rd Edition, 2007
[2] Klaus Weissermel, and Hans-Jürgen Arpe, Industrial Organic Chemistry, 3rd Edition, 1997
[3] George A. Burdock, Fenaroli’s Handbook of Flavor Ingredients, 4th Edition, 2001
Description
The commercial grade of 4-methyl-3-penten-2-one exhibits an unpleasant grassy-green or pungent, acrylic 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/m
3 (17 ppb
v) and
200 μg/m
3 (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
Uses
4-Methyl-4-penten-2-one is used to a
small extent as an intermediate in synthesis. Most
of it is converted to 4-methyl-2-pentanone by
selective hydrogenation. Although 4-methyl-2-
pentanone has excellent solvent properties for
nitrocellulose, cellulose esters and ethers, copolymers of vinyl chloride – vinyl acetate and
other synthetic resins, as well as natural and
synthetic rubber, its use as a solvent is limited
as a result of its toxicity and chemical instability.
The fraction of 4-methyl-4-penten-2-one permitted in solvent systems has been set at 5 vol%
(Rule 66 of the Los Angeles, California, Air
Pollution Control District).
Some of the numerous possible reactions that
mesityl oxide may undergo have been used for
the synthesis of products such as Budralazine, an
antihypertensive agent.
Uses
Solvent for nitrocellulose, many gums and resins, particularly vinyl resins. In lacquers, varnishes and enamels. In making methyl isobutyl ketone.
Definition
ChEBI: 4-Methyl-3-penten-2-one, 9CI is an olefinic compound. It is functionally related to an acrylic acid.
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.
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.
Toxics Screening Level
The initial threshold screening level for mesityl oxide is 400 μg/m3 based on an 8-hour averaging time.
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.
