Difference Between Isopropyl and Rubbing Alcohol

Isopropyl vs Rubbing Alcohol
 

Isopropyl alcohol and rubbing alcohol are categorized under the alcohol group, since they have a –OH group. These are the smaller alcohols in the series with two or three carbons. The OH group is attached to a sp³ hybridized carbon. Both are polar liquids and have the capability to form hydrogen bonds. Therefore, both have somewhat similar physical and chemical properties. For example, both are flammable and toxic liquids.

Isopropyl Alcohol

Isopropyl alcohol, which is also known as 2-propanol, has the same molecular formula as propanol. The molecular weight of it is around 60 g mol^-1. The molecular formula is C₃H₈O. Hence, isopropyl alcohol is an isomer of propanol. The hydroxyl group of this molecule is attached to the second carbon atom in the chain. Therefore, this is a secondary alcohol. Melting point of isopropyl alcohol is -88 ^oC, and the boiling point is 83 ^oC. It is miscible with water and stable under normal conditions. This is a colorless, clear, flammable liquid. It has a strong odor. Since this is a secondary alcohol, it undergoes all the reactions typical to a secondary alcohol. It oxidizes violently to produce acetone. This alcohol is used as a solvent, in pharmaceuticals, household products, personal care products and to make other chemicals.

Rubbing Alcohol

Ethanol is a simple alcohol with the molecular formula of C₂H₅OH. It is a clear, colorless liquid with a characteristic odor. Furthermore, ethanol is a flammable liquid. Melting point of ethanol is -114.1 ^oC, and the boiling point is 78.5 ^oC. Ethanol is polar due to the electronegativity difference between the oxygen and hydrogen in the –OH group. Also, due to –OH group, it has the ability to form hydrogen bonds. Ethyl alcohol is used as a beverage. According to the ethanol percentage, there are different types of beverages such as wine, beer, whiskey, brandy, arrack etc. Denatured alcohol is ethanol with other additives, which makes it unfavorable for drink. This is also known as methylated spirits because earlier, the main additive for this was methanol which is about 10%. Other than methanol, other additives like isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and denatonium are also added to make denatured alcohol. Addition of these extra molecules doesn’t affect the chemical nature of the ethanol but makes it highly poisonous. Sometimes denatured alcohol may have a color due to the addition of dyes.

Rubbing alcohol is a type of denatured alcohol. It has 70-95% ethanol and some other additives. Therefore as stated above it is highly poisonous and not suitable for consumption. It is mainly used as a disinfectant on human skin.  It is also used to clean medical equipment so that they will be free from bacteria and fungi. Other than normal rubbing alcohol, there is another type called isopropyl rubbing alcohol, which consists mainly of isopropyl alcohol. It is mainly used as a solvent or a cleaner.

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