tert-Butyl acetate

Chemical Properties

tert-Butyl acetate or t-butyl acetate is a colorless flammable liquid with a camphoror blueberry-like smell. It is used as a solvent in the production of lacquers, enamels, inks, adhesives, thinners, and industrial cleaners. It is also used as an additive to improve the antiknock properties of motor fuels. tert-Butyl acetate has three isomers: n-butyl acetate, isobutyl acetate, and sec-butyl acetate.

Physical properties

Colorless liquid with a fruity odor. Odor threshold concentration in water is 4 ppm (CHRIS, 1994). Nagata and Takeuchi (1990) reported an odor threshold concentration of 71 ppb_v.

Uses

tert-Butyl acetate is common industrial solvent used in the making of lacquers, artificial leather, airplane dope, perfume, and as a food additive. It has recently gained EPA volatile organic compound (VOC) exempt status.

Production Methods

tert-Butyl acetate is prepared from isobutylene reacting with acetic acid in the liquid phase with vanadium pentoxideimpregnated silica as the catalyst and with heat to increase the yield .

Synthesis Reference(s)

Organic Syntheses, Coll. Vol. 3, p. 142, 1955
Synthesis, p. 1015, 1987
Tetrahedron Letters, 37, p. 4555, 1996 DOI: 10.1016/0040-4039(96)00902-1

Air & Water Reactions

Highly flammable. Insoluble in water.

Reactivity Profile

tert-Butyl acetate is an ester. Esters react 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. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing esters with alkali metals and hydrides. tert-Butyl acetate is incompatible with the following: Nitrates; strong oxidizers, alkalis & acids .

Health Hazard

Exposure to tert-butyl acetate causes eye, skin, and respiratory irritation in workers. By analogy with the effects of exposure to similar esters, tert-butyl acetate may act as a CNS depressant at high concentrations. The signs and symptoms of acute exposure to tert-butyl acetate include, but are not limited to, itchy or inflamed eyes and irritation of the nose and upper respiratory tract. Exposures to tert-butyl acetate at high concentrations may cause headache, drowsiness, and other narcotic effects.

Safety Profile

Poison by inhalation and ingestion. Flammable. To fight fire, use alcohol foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes.

Environmental Fate

Chemical/Physical. Hydrolyzes in water to tert-butyl alcohol and acetic acid. The estimated hydrolysis half-life at 25 °C and pH 7 is 140 yr (Mabey and Mill, 1978).

storage

tert-Butyl acetate should be stored in a cool, dry, well-ventilated area in tightly sealed containers that are labeled in accordance with regulatory standards. Containers of tert butyl acetate should be protected from physical damage and should be stored separately from nitrates, strong oxidizers, strong acids, strong alkalis, heat, sparks, and open flame. Because containers that formerly contained tert-butyl acetate may still hold product resi dues, they should be handled appropriately

Shipping

UN1123 Butyl acetates, Hazard Class: 3; Labels: 3—Flammable liquid.

Purification Methods

Wash the ester with 5% Na2CO3 solution, then saturated aqueous CaCl2, dry with CaSO4 and distil it. [McClosky et al. Org Synth Coll Vol IV 263 1963, Mangia et al. Org Prep Proc Int 18 13 1986, Beilstein 2 IV 151.]

Incompatibilities

All butyl acetates are incompatible with nitrates, strong oxidizers; strong alkalies; strong acids. Tert-Butyl acetate may form explosive mixture with air; reacts with water, on standing, to form acetic acid and n-butyl alcohol. Violent reaction with strong oxidizers and potassium-tert-butoxide. Dissolves rubber, many plastics, resins and some coatings. May accumulate static electrical charges, and may cause ignition of its vapors.

Toxics Screening Level

The Initial Threshold Screening Level (ITSL) is 2372 μg/m3 with an annual 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.

Precautions

If exposures to tert-butyl acetate or a solution in work areas gets into the eyes, immediately fl ush the eyes with large amounts of water for a minimum of 15 min, lifting the lower and upper lids occasionally. Always use safety goggles or eye protection in combination with breathing protection.