What is a reasonable method to remove the small amount of acetic anhydride present in methyl acetoacetate?
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The boiling points of acetic anhydride and methyl acetoacetate are quite similar; distillation should be used, as it is not possible to remove acetic anhydride in this way； If sulfuric acid or a base is used, it reacts not only with acetic anhydride but also with methyl acetoacetate ； Therefore, no suitable method has been found yet; I hope those who have experience in this area can share their insights. Thank you. This post was last edited by lxzzl on 2009-2-25 at 12:07.]
Welcome everyone to discuss this. I really have no idea what to do; the entire project has come to a standstill
Add a substance that boils with the ester at a lower boiling point, and then separate it from the anhydride. This substance is then separated from the ester by pressure swing separation.
Since the amount of acetic anhydride is small, a low-boiling organic compound that is azeotropic with acetic anhydride should be used to remove it through azeotropy! ! ! !
This azeotrope may introduce new impurities during the separation process
You might try using silicon tetrachloride; acetic anhydride reacts with silicon tetrachloride to form acyloxysilanes. Acetyl chloride, on the other hand, has a boiling point of only 52 degrees, while acyloxysilanes have a boiling point of over 300 degrees, making them easy to separate
Thank you to the person above; I’m not sure if this method can remove very small amounts of acetic anhydride
For the separation of substances with boiling points that are very close to each other, azeotropic distillation is generally used. We have also worked on some similar projects before. . . . It’s difficult to find a suitable reagent. . . You need to take into comprehensive consideration the physical properties of the relevant substances as well as the goal you wish to achieve. . . You could try something like alumina; I believe it will work well. . . For reference only
How can az alumina, being a solid, be subjected to azeotropic distillation?
Thank you to the fellow travelers above; the work related to acetic anhydride for this project has been completed. Thank you very much