[Chemistry Lab] Isolation of Aldehyde and Carboxylic Acid

In summary, the conversation is about a chemistry lab involving the Cannizzaro Reaction. The lab consists of reacting an unknown aldehyde with methanol and KOH. The questions asked include calculating the amount of 6M HCL needed to neutralize the reaction mixture, determining the % yield of furfural alcohol and furoic acid, and finding ways to isolate the alcohol and carboxylic acid products after condensation.
  • #1
jkh4
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[Chemistry Lab] Cannnizzaro Reaction

Hi! I am having some questions about my chemistry lab.

In the lab we are given 1 of the 5 unknown aldehyde (benzaldehyde, anisaldehyde, nitrobenzaldehyde, chlorobenzaldehyde, and dimethoxybenzaldehyde) and reacts it with methanol and KOH to undergo Cannizzaro Reaction.

1) To calculate the amount of 6M HCL that need to neutralize and acidify (to ~pH 2) the reaction mixture once the reaction is complete.

2) A total of 3.12g of furfural was treated under Cannnizzaro conditions to produce 0.84g of furfural alcohol and 0.75g of furoic acid. What is the % Yield of each product.

For this question i got 26.37% for furfural alcohol and 20.61% furoic acid. I just want to confirm if i got it right.

3) After condensation, what are some good ways to isolate the alchohol and carboxylic acid products that are formed in the reaction?

THANKS!
 
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  • #2
jkh4 said:
Hi! I am having some questions about my chemistry lab.

In the lab we are given 1 of the 5 unknown aldehyde (benzaldehyde, anisaldehyde, nitrobenzaldehyde, chlorobenzaldehyde, and dimethoxybenzaldehyde) and reacts it with methanol and KOH to undergo Cannizzaro Reaction.

1) To calculate the amount of 6M HCL that need to neutralize and acidify (to ~pH 2) the reaction mixture once the reaction is complete.

2) A total of 3.12g of furfural was treated under Cannnizzaro conditions to produce 0.84g of furfural alcohol and 0.75g of furoic acid. What is the % Yield of each product.

For this question i got 26.37% for furfural alcohol and 20.61% furoic acid. I just want to confirm if i got it right.

3) After condensation, what are some good ways to isolate the alchohol and carboxylic acid products that are formed in the reaction?

THANKS!


Are you sure that methanol was used in this "Cannizzaro" reaction? It sounds more like an aldol...
 
  • #3


Hello! It sounds like you are working on a very interesting and challenging lab. I am happy to provide some feedback and answer your questions.

1) To calculate the amount of 6M HCl needed to neutralize and acidify the reaction mixture, you will need to know the concentration of the aldehyde and the volume of the reaction mixture. From there, you can use the balanced chemical equation to determine the moles of aldehyde present and then use that to calculate the moles of HCl needed. Finally, you can convert the moles of HCl to the volume needed using the molarity equation (M = moles/liters). It is important to note that the reaction mixture may not be completely neutralized with just one addition of HCl, so you may need to titrate with smaller amounts to reach the desired pH of 2.

2) Your calculated percent yields for furfural alcohol and furoic acid seem to be correct. However, it is always a good idea to double check your calculations and units to make sure they are accurate.

3) After condensation, the alcohol and carboxylic acid products can be isolated using techniques such as distillation, extraction, or crystallization. Distillation can be used if the products have significantly different boiling points, while extraction can be used if one of the products is soluble in a specific solvent. Crystallization can also be used to separate the products if one of them is more soluble in a certain solvent. It is important to keep in mind the physical properties of the products when deciding on the best method for isolation.
 

1. What is the purpose of isolating aldehyde and carboxylic acid in a chemistry lab?

The purpose of isolating aldehyde and carboxylic acid is to separate and purify these two compounds from a mixture. This allows for further analysis and identification of each individual compound.

2. How do you isolate aldehyde and carboxylic acid in a chemistry lab?

Isolation of aldehyde and carboxylic acid involves several steps, including extraction, distillation, and purification through recrystallization or chromatography. The process may vary depending on the specific compounds being isolated and the equipment available in the lab.

3. What are the properties of aldehyde and carboxylic acid that make them suitable for isolation?

Aldehyde and carboxylic acid have distinct physical and chemical properties that allow for their separation. Aldehydes have a lower boiling point and are more volatile, while carboxylic acids have a higher boiling point and are more polar. This difference in properties enables their separation through distillation and extraction.

4. What are the potential hazards associated with isolating aldehyde and carboxylic acid in a chemistry lab?

Some potential hazards include the flammability and toxicity of aldehydes and carboxylic acids, as well as the risks associated with handling concentrated acids and using distillation equipment. Proper safety precautions, such as wearing protective gear and working in a well-ventilated area, should be taken when conducting this experiment.

5. What are some applications of isolated aldehyde and carboxylic acid in the field of chemistry?

Isolated aldehyde and carboxylic acid can be used for further analysis and identification in various industries, such as pharmaceuticals, food and beverage, and cosmetics. They can also be used as starting materials for the synthesis of other compounds in organic chemistry reactions.

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