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What kind of molar proportions should i think of when dehydrating a carboxylic acid with P2O5?
Accepted Answer
P₂O₅ is a powerful dehydrating agent that removes water from carboxylic acids to form anhydrides. The molar ratio of P₂O₅ to carboxylic acid depends on the specific anhydride you want to form.
For example, to form a symmetrical anhydride from a single carboxylic acid, the ideal molar ratio is 1:2 (P₂O₅ : carboxylic acid).
Here's a general guideline:
Symmetrical anhydrides: 1 mole of P₂O₅ : 2 moles of carboxylic acid
Mixed anhydrides: 1 mole of P₂O₅ : 1 mole of each carboxylic acid
Remember that the actual amount of P₂O₅ required may vary depending on the specific reaction conditions and desired yield. It's generally a good idea to use a slight excess of P₂O₅ to ensure complete dehydration.
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