| Overview |
| Instructions |
| Operating scheme |
| Substances |
| Equipment |
| Evaluation |
| Analytics |
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; Side reactions |
Synthesis of p-methoxyacetophenone from anisole |
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Synthesis instructions as PDF file for printing |
ReactionDrying of Scandium(III) triflate: Heat 4.90 g (10.0 mmol) of Sc(OTf)3 for 1 hour in an evacuated (approx. 1 hPa) 500 mL three-neck flask with nitrogen and vacuum inlet to 180 °C in an oil bath to remove all moisture. Inflate the flask with nitrogen. After cooling to room temperature, the flask is equipped with reflux condenser with drying tube, pressure equalizing dropping funnel and internal thermometer while maintaining a nitrogen atmosphere. Charge the flask with 60 mL of nitromethane via the dropping funnel and stir for 10 minutes. Add, again using the dropping funnel, 5.40 g (5.45 mL, 50.0 mmol) of anisole and 5.10 g (4.7 mL, 50.0 mmol) of acetic anhydride. The reaction mixture is heated with stirring for 6 hours to 50 °C internal temperature.Work upAfter cooling to room temperature, add 150 mL of water and transfer the mixture into a separating funnel. The organic phase is separated and the aqueous phase extracted twice with 70 mL of tert-butyl methyl ether. Wash the combined organic phases with 100 mL of brine, and dry over magnesium sulfate. The magnesium sulfate is removed by filtration and the solvent removed at a rotary evaporator to yield a slightly yellow residue as crude product.Crude product yield: 7.81 g; Purity according to GC: 96% The crude product is distilled in a microdistillation apparatus in vacuum  .Yield: First fraction: 0.49 g, bp up to 100 °C (0.6 hPa). GC shows 2% ortho-methoxyacetophenone beside para-methoxyacetophenone Second fraction: bp = 110 °C (0.6 hPa); colourless liquid, which rapidly solidifies; purity according to GC 99% Residue of distillation: 1.24 g of tar. Duration of the experiment11 hours, without recovery of the scandium triflateWhere can I stop the experiment?Before work up and before distillationRecyclingRecovery of the catalyst: Concentrate the combined aqueous phases with the rotary evaporater as far as possible. The remaining crystalline residue is dried in vacuum (approx. 1 hPa) at 180 °C for 20 hours. Yield of recovered scandium(III) triflate 3.50 g (70% of the amount originally used in the reaction). Fresh and recovered scandium catalysts give the same results in the reaction. |
Suggestions for waste disposal |
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