What reagents are used to distinguish ether and alcohol

1. Reagent Selection and Basic Principles

The key to distinguish between ethers and alcohols is the difference in their physical and chemical properties. Ether compounds usually have no obvious odor, while alcohol compounds may have a faint fragrance. Based on this, one can preliminarily judge the general type of substance. In order to identify more accurately, it is usually necessary to combine chemical reagents to distinguish.

1. Bromine water Bromine water is a commonly used reagent, especially suitable for distinguishing ethers from alcohols. Bromine water can react with alcohols in organic solvents, while ether compounds usually do not react with bromine water, so obvious differences in phenomena can be observed.

2. Acidification of potassium permanganate solution with sulfuric acid Potassium permanganate solution under acidic conditions is a strong oxidant and can be used to distinguish between alcohols and ethers. The specific mechanism of action is similar to that of bromine water, but requires a specific acidic environment.

3. acidic potassium dichromate reagent Acidic potassium dichromate reagent is a more specific reagent that is commonly used to distinguish ketones from alcohols. Due to the structural characteristics of ether compounds, their reaction with acidic dichromic acid is different from alcohol.

4. iodine vapor Iodine vapor can undergo a color reaction with alcohols under alkaline conditions, while ether compounds are generally unreactive. This phenomenon can be used to distinguish ethers from alcohols.

2. bromine water use

The addition reaction of bromine water with organic compounds is the basis for distinguishing ethers from alcohols. The specific operation is as follows:

1. Reagent preparation Pour the bromine water evenly into the test tube, ensuring that the solution is saturated.

2. Add the substance to be tested The ether or alcohol sample to be tested is slowly added to the bromine water and the phenomenon is observed by shaking.

3. observation phenomenon Phenolic compounds (such as ethers) and bromine water will undergo addition reactions, resulting in a white precipitate, and may have a weak odor. The alcohol compound (such as alcohol) usually does not react with bromine water, and the color of the solution remains unchanged.

4. Conclusion If precipitation is observed, it is an ether compound; if there is no obvious reaction, it is an alcohol compound.

3. Sulfuric Acid Acidizing Potassium Permanganate Solution

Sulfuric acid acidified potassium permanganate solution is a strong oxidizing reagent, can be used to distinguish between alcohol and ether. The specific operation steps are as follows:

1. Reagent preparation The potassium permanganate solution is subjected to the necessary acidification treatment in an acidic environment (usually using sulfuric acid or hydrochloric acid).

2. Add sample to be tested The ether or alcohol sample to be tested is added to the acidified potassium permanganate solution and gently shaken or allowed to stand.

3. observation phenomenon Phenolic compounds (such as ethers) generally do not react with the potassium permanganate solution and the color of the solution remains unchanged. Alcohols (such as alcohols) may react with potassium permanganate to produce a purple dichromate solution.

4. Judgment basis If the color of the solution changes to purple, it is an alcohol compound; if there is no change, it is an ether compound.

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4. Acidic Potassium Dichromate Reagent Use

Acidic potassium dichromate reagent is a specific reagent that is commonly used to distinguish ketones from alcohols. Although the mechanism of action is somewhat different from the reagents that distinguish between ethers and alcohols, the principle is similar:

1. Reagent preparation The acidic potassium dichromate reagent usually needs to be used under acidic conditions, and sulfuric acid or hydrochloric acid can be used for acidification.

2. Add sample to be tested The ether or alcohol sample to be tested is added to the acidic potassium dichromate solution and gently shaken or allowed to stand.

3. observation phenomenon Phenolic compounds, such as ethers, generally do not react with acidic potassium dichromate and the color of the solution remains unchanged. Alcohols (e. g., alcohols), on the other hand, may oxidize with acidic potassium dichromate, and the color varies depending on the progress of the oxidation reaction.

4. Judgment basis Depending on the color change or the reaction rate, it can be determined whether the substance to be tested is an alcohol compound.

5. Iodine Vapor Use

Iodine vapor is a commonly used reagent that can be used to distinguish ethers from alcohols. The reaction mechanism is as follows:

1. Reagent preparation The iodine vapor is volatilized at an appropriate temperature to allow it to exist in the form of elemental iodine in the solution.

2. Add sample to be tested The ether or alcohol sample to be tested is added to the iodine vapor environment, which can usually be heated by means of a water or oil bath.

3. observation phenomenon Phenolic compounds (such as ethers) generally do not react with iodine vapor and the solution color remains unchanged. Alcohols (such as alcohols) may react with iodine vapor under alkaline conditions, resulting in blue or purple precipitates.

4. Judgment basis If a blue or purple precipitate is observed, it is an alcohol compound; if there is no reaction, it is an ether compound.

6. summary

Through the use of the above reagents, ethers and alcohols can be distinguished more accurately. It should be noted that although these reagents can effectively distinguish between the two compounds, it may be necessary to combine multiple methods for comprehensive analysis in practical applications to improve the accuracy and reliability of identification. The use conditions, concentration ratio and reaction environment of the reagents may affect the experimental results, so it is necessary to strictly follow the instructions of the reagents during the operation to ensure the scientificity and rigor of the experiment.