Suppose your assignment were to prepare the Glaser type product of a mixed reaction of a phenyl acetylene and propyne. How might the procedure in this experiment be modified so that the mixed product can be most efficiently isolated?
To efficiently isolate the mixed product of a Glaser-type reaction between phenyl acetylene and propyne, you can modify the procedure by following these steps:
1. Begin by setting up a typical Glaser-type reaction, where phenyl acetylene and propyne are mixed in the presence of a copper(I) catalyst and a suitable solvent such as acetonitrile.
2. Once the reaction is complete, perform a work-up step involving the addition of water. This will quench the reaction and help to separate the product from the reaction mixture.
3. After adding water, separate the organic layer from the aqueous layer. This can be done by using a separatory funnel or by simply decanting the layers carefully.
4. Next, dry the organic layer to remove any water present. This can be achieved by adding anhydrous salts, such as magnesium sulfate or sodium sulfate, to absorb the remaining moisture. Allow the mixture to stir or gently shake for some time and then filter to remove the drying agent.
5. Concentrate the organic layer by removing the solvent. You can use a rotary evaporator under reduced pressure to evaporate off the acetonitrile or any other solvent used.
6. Once the solvent is removed, you can further purify the product by using column chromatography. This technique helps separate different components of the mixture based on their polarity. By using an appropriate solvent system and an appropriate stationary phase, you can isolate the mixed product from impurities or unreacted starting materials.
7. Finally, analyze the collected fractions from the column chromatography using techniques like TLC (thin-layer chromatography) or NMR (nuclear magnetic resonance) spectroscopy to confirm the identity and purity of the isolated mixed product.
By following these modified steps, you should be able to efficiently isolate the mixed product of the Glaser-type reaction between phenyl acetylene and propyne.