Simple chemical test to distinguish between ethanol and phenol

Simple chemical test to distinguish between ethanol and phenol

in chemical experiments, ethanol (C₂ H∞OH) and phenol (C≡H∞OH) are two common organic compounds. Although they have similar chemical structures, there are significant differences in properties. Therefore, how to distinguish ethanol from phenol by simple chemical tests has become an important issue in many chemical experiments. This article will analyze in detail several simple and effective chemical testing methods to help you easily distinguish between these two chemicals.

1. Acidic difference: phenol is more acidic

One of the main differences between ethanol and phenol is their acidity. The hydroxyl group (-OH) in the phenol molecule is connected to the benzene ring, forming a relatively strong acidity. In contrast, the hydroxyl group in ethanol is only linked to the ethyl group, which is less acidic. Therefore, the two can be clearly distinguished by a simple acid-base reaction.

Chemical Testing: The acidic reaction of the two was tested with sodium hydroxide solution (NaOH). Phenol reacts with sodium hydroxide to produce sodium phenolate and water, while ethanol does not react similarly. Specific reactions are as follows:

• Phenol NaOH → Phenol sodium H₂ O
• Ethanol NaOH → No obvious reaction

By this test, phenol will show an acidic reaction, while ethanol will not change significantly, so this is a simple method to distinguish between ethanol and phenol.

2. Oxidation reaction: ethanol oxidation

Under certain conditions, ethanol can be oxidized and converted into acetaldehyde or acetic acid. Phenol does not readily undergo such an oxidation reaction. Therefore, the oxidation reaction can also be used to distinguish between the two species.

Chemical Testing: The tests were carried out using an acidic potassium permanganate solution (KMnO₂). Ethanol can be oxidized by potassium permanganate under oxidizing conditions, and the reaction will cause the color of the solution to change from purple to colorless or light brown. The oxidation reaction of phenol to potassium permanganate is not significant, and the color change of the solution is small.

Through the oxidation test of potassium permanganate, it can be effectively judged whether it is ethanol. If the color of the solution changes obviously, the sample may be ethanol; if the change is not obvious, it is likely to be phenol.

3. Odor contrast: ethanol and phenol odor difference

In everyday life, the difference in odor between ethanol and phenol can also help distinguish between the two. Ethanol has a fragrant smell similar to alcohol, while phenol emits a pungent, drug-like odor.

Chemical Testing: The type of sample can be preliminarily judged by the method of smell. Ethanol smells fresh and not pungent, while phenol has a pronounced pungent and pungent odor. However, this test method is suitable for use with a small sample volume and requires attention to the irritation of phenol, so it should be performed in a well-ventilated area.

4. Solubility difference: ethanol and phenol solubility

In terms of solubility, ethanol and phenol also have differences. Ethanol can be miscible with water in any proportion, while phenol has low solubility in water, especially at low temperatures. Taking advantage of this, you can help distinguish between the two with a simple dissolution test.

Chemical Testing: A small amount of sample was added to the water separately. Ethanol will be completely dissolved in water, while phenol will be partially dissolved in water, and the remaining phenol may float on the water surface. With this simple solubility test, you can determine the type of sample.

5. Summary

Through the above several simple chemical tests, we can effectively perform simple chemical tests to distinguish ethanol from phenol. These test methods include acid-base reaction, oxidation reaction, odor contrast and solubility test. Each method has its unique advantages and can be flexibly selected according to actual needs. Through these simple experiments, chemistry enthusiasts and experimenters can easily judge and distinguish between the two chemicals.