Ethanol is a volatile, flammable, simple, organic alcohol. Available in various reagent grades, it has applications as a lab/medicinal solvent, an antiseptic, a fuel source/additive, a precursor to organic compounds, etc.

Denatured alcohol (CAS 64-17-5), also known as denatured ethanol or industrial methylated spirit (IMS), is ethanol (ethyl alcohol) to which has been added small known quantities of other substances, so as to ‘denature’ or adulterate it in a controlled manner.

What Additives are Used in Denatured Alcohol?
Often, the additive is methanol (at 5 to 10%), but isopropanol (IPA), methyl ethyl ketone (MEK), acetone or methyl isobutyl ketone (typically all at 1%) may be used. Denatonium can be added for a bitter taste, colored dyes such as methyl violet for visual identification, or a combination may also be used. The purpose of these additives is to create ethanol that is not suitable for human consumption.

The primary purpose of denaturation is to render the ethanol unfit, unpalatable, and unsafe for recreational human consumption, or unsuitable for any other unauthorized purpose. Denaturation usually makes the product exempt from duty payable and other taxes, making it cheaper to purchase.

How Is Denatured Alcohol Used?
Denatured alcohol is used commercially and in industry:
• As a general-purpose solvent, especially for removal of adhesives, waxes, and paint
• For cleaning and degreasing apparatus and equipment
• As a fuel for burners and stoves
• As a surface disinfectant or sterilizer for use in cleanrooms, laboratories, and clinical environments, presented as a liquid, spray, gel, or pre-moistened wiper
• As a preservative and antibacterial agent in cosmetics

Denatured alcohol with added methanol is acutely toxic. It is flammable at room temperature and storage in a secure location is recommended. Due attention should also be given to all other appropriate precautions necessary for handling these chemicals.