ChemicalSolution (Stranger) 12-22-01 16:42 No 249811 |
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GAA--> ac2O + H2O with heating however this is an equilibrium process and consequently we cannot heat GAA to 140 and distill it over as ac2O. How about dripping GAA onto concentrated H2SO4? One would think that the H2SO4 would dehydrate the GAA and form the anhydride. This dream would probably start out by cooling 1.1 moles of H2SO4 on an ice bath and then dripping 1 mole GAA onto the H2SO4 then heating until distillation. Does anyone think this would work?--CH |
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lugh (Hive Bee) 12-22-01 18:13 No 249833 |
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ChemicalSolution (Stranger) 12-23-01 07:00 No 249961 |
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What about heating GAA with phthalic anhydride? There has to be a way besides working through acetyl chloride. |
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terbium (Old P2P Cook) 12-23-01 07:15 No 249964 |
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There has to be a way besides working through acetyl chloride. There is. It is called ketene. |
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uemura (Hive Photographer) 12-23-01 09:03 No 250000 |
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Uemura would try P2O5 instead of phthalic anhydride: x GAA + y P2O5 -> z Ac2O + Phosphour acid Merry XMas to the Bees |
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ChemicalSolution (Newbee) 12-25-01 07:03 No 250332 |
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Would phthalic anhydride work though? It is MUCH cheaper for SWIM. Besides, it can be re-generated. Lets say someone did a batch with 1mole GAA and, say, 1.2 mole phthalic anhydride. The ac2O is distilled over and what's left in the flask is heated to 200C to melt. This will free H20 and regenerate the anhydride. But really, back to the original question. What would happen if you refluxed GAA with H2SO4? We already know that GAA heated forms acO2 and H2O. Would the water NOT ionize with the H2SO4 present, shifting the equalibrium toward anhydride synthesis? |
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