To selectively obtain an aldehyde from a primary alcohol oxidation with dichromate, which technique is employed?

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Multiple Choice

To selectively obtain an aldehyde from a primary alcohol oxidation with dichromate, which technique is employed?

Selective oxidation can stop at the aldehyde if the product is removed as it forms. With a strong oxidant like dichromate, the primary alcohol tends to be oxidized all the way to the carboxylic acid unless the aldehyde is taken out of contact with the oxidant. Distillation during oxidation achieves this by continuously removing the aldehyde as it forms, so it spends minimal time in the reacting mixture. This shifts the process away from further oxidation and lets you isolate the aldehyde. Refluxing the mixture until the reaction is complete would allow the aldehyde to be further oxidized to the acid. Crystallization isn’t applicable here because aldehydes from this reaction are typically liquids, not solids. Extraction separates components but won’t prevent the aldehyde from being oxidized if it remains in contact with the oxidant.

Selective oxidation can stop at the aldehyde if the product is removed as it forms. With a strong oxidant like dichromate, the primary alcohol tends to be oxidized all the way to the carboxylic acid unless the aldehyde is taken out of contact with the oxidant. Distillation during oxidation achieves this by continuously removing the aldehyde as it forms, so it spends minimal time in the reacting mixture. This shifts the process away from further oxidation and lets you isolate the aldehyde.

Refluxing the mixture until the reaction is complete would allow the aldehyde to be further oxidized to the acid. Crystallization isn’t applicable here because aldehydes from this reaction are typically liquids, not solids. Extraction separates components but won’t prevent the aldehyde from being oxidized if it remains in contact with the oxidant.

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