The key difference between ethyl alcohol and isopropyl alcohol is that ethyl alcohol is a primary alcohol while isopropyl alcohol is a secondary alcohol.
Ethyl alcohol and isopropyl alcohol are alcoholic compounds 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 an sp3 hybridized carbon. Both are polar liquids and have the ability to form hydrogen bonds. Therefore, both of these compounds have somewhat similar physical and chemical properties along with some differences too.
CONTENTS
1. Overview and Key Difference
2. What is Ethyl Alcohol
3. What is Isopropyl Alcohol
4. Side by Side Comparison – Ethyl Alcohol vs Isopropyl Alcohol in Tabular Form
5. Summary
What is Ethyl Alcohol?
Ethyl alcohol is what we know commonly as ethanol. Ethanol is a simple alcohol with the molecular formula of C2H5OH. It is a clear, colorless liquid with a characteristic odor. Furthermore, this compound is a flammable liquid. Its melting point is -114.1oC and boiling point is 78.5oC. Ethanol is polar due to the electronegativity difference between the oxygen and hydrogen in the –OH group. Also, due to –OH group, it can form hydrogen bonds.
Figure 1: Alcoholic Beverage
Ethyl alcohol is very useful as a beverage. According to the ethanol percentage, there are different types of beverages such as wine, beer, whiskey, brandy, arrack, etc. Ethanol can be easily obtained by the sugar fermentation process using the zymase enzyme. The enzyme is naturally present in yeast; thus, in anaerobic respiration, yeast can produce ethanol. Moreover, this ethanol is toxic to the body, and it is converted to acetaldehyde in the liver, which is also toxic. In addition, it is useful as an antiseptic to clean surfaces by removing microorganisms. Moreover, we can use it as a fuel and a fuel additive in vehicles. Ethyl alcohol is miscible with water, and it serves as a good solvent as well.
What is Isopropyl Alcohol?
Isopropyl alcohol, which is also known as 2-propanol, has the same molecular formula as propanol. Its molecular weight 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 carbon chain. Therefore, this is a secondary alcohol.
Figure 2: Chemical Structure of Isopropyl Alcohol in a Ball-Stick Model
Moreover, the melting point of isopropyl alcohol is -88oC, and the boiling point is 83oC. It is miscible with water and stable under normal conditions. This is a colorless, clear, flammable liquid. Since this is a secondary alcohol, it undergoes all the reactions typical to a secondary alcohol. Furthermore, it oxidizes violently to produce acetone. As for usage, this alcohol is useful as a solvent and used in pharmaceuticals, household products, and personal care products. We can also use it to make other chemicals.
What is the Difference Between Ethyl Alcohol and Isopropyl Alcohol?
Ethyl alcohol is ethanol, and isopropyl alcohol is 2-propanol. These are small alcoholic compounds. The key difference between ethyl alcohol and isopropyl alcohol is that ethyl alcohol is a primary alcohol while isopropyl alcohol is a secondary alcohol. Moreover, an important difference between ethyl alcohol and isopropyl alcohol is that the ethyl alcohol has two carbons while isopropyl alcohol has three carbons.
When considering the nomenclature of these compounds, in ethyl alcohol nomenclature, the carbon with – OH group gets number one. In isopropyl nomenclature, the carbon with -OH group gets number two. Apart from that, when isopropyl alcohol is oxidized, acetone is produced. However, an aldehyde is produced from ethyl alcohol oxidation. Furthermore, one other significant difference between ethyl alcohol and isopropyl alcohol is that the ethyl alcohol is suitable for drinking, but isopropyl alcohol is not. In fact, Isopropyl alcohol consumption can be toxic.
Summary – Ethyl Alcohol vs Isopropyl Alcohol
Ethyl alcohol and isopropyl alcohol are two different types of alcoholic compounds; they are the smallest alcohols that come after methanol. The key difference between ethyl alcohol and isopropyl alcohol is that ethyl alcohol is a primary alcohol while isopropyl alcohol is a secondary alcohol.
Reference:
1. Helmenstine, Anne Marie, Ph.D. “The Difference Between Alcohol and Ethanol.” ThoughtCo, Jan. 13, 2019, Available here.
2. Wade, Leroy G. “Isopropyl Alcohol.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 26 Nov. 2018, Available here.
Image Courtesy:
1. “816826” (CC0) via Pxhere
2. “Propan-2-ol-3D-balls” By Jynto (talk) – Own work – created with Discovery Studio Visualizer (CC0) via Commons Wikimedia