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Topic: Strange Esterification Product  (Read 1550 times)

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Offline mdb1800

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Strange Esterification Product
« on: May 09, 2018, 06:39:00 AM »
Hi,

Under reflux, an imprecise quantity of Salicylic Acid (1 teaspoon), was combined with 10ml of Methanol, with about 10 drops of Conc. H2SO4. We had the heating mantle going for about 40 mins, and we could see that no gas was escaping (got about 2/3 of the way up the condenser). Smelt very much of Bengay.

To seperate the products, we were going to to add sodium bicarbonate and then use a separation funnel to seperate the ester. However, when we added the sodium bicarbonate, a precipitate formed almost instantly. We continued to add sodium bicarbonate until we could hear no bubbling. We filtered off the liquid using a filter paper and collected the crystals. They smelt a lot of Methyl Salicylate. We added sodium bicarbonate to the filtrate and it distorted (almost like alcohol in water) but nothing else happened.

That brings me to my question, I'm confused as the why the Methyl Salicylate was solid, as the boiling point should be ~-2 deg. celsius. What is our product? My thinking is that it could be salicylic acid, but I really doubt that there would be that must, plus, it's polar and should have reacted with the sodium bicarbonate. Any thoughts?

Offline kriggy

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Re: Strange Esterification Product
« Reply #1 on: May 09, 2018, 08:45:20 AM »
THe methyl salicilate has MELTING point -9°C and boiling point about 220°C.
Im not sure but from the procedure, I would guess that your crystals are not methyl salicilate but rather sodium sulfate which is insoluble in organic solvents (MeOH) and its solubility in water is not great either.

Offline hypervalent_iodine

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Re: Strange Esterification Product
« Reply #2 on: May 09, 2018, 10:52:49 AM »
Definitely not your product. I have done this exact reaction and get a clear oil, in about 75% yield unoptimised.

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