This is for a phase catalysis lab experiment
1. How is the phase transfer catalyst removed from the product? I said, by washing it with salt.
2. what purpose does washing with 15% (half-saturated) NaCl solution serve? I said, to remove bulk of water
3. There is a slight excess of sodium benzoate in the reaction. How is it removed from the product? I said, by boiling the reaction
4. Why is the benzoate anion a stronger nucleophile in 1-bromobutane than in water solution? I do not know this answer.
Please help. I have been trying to figure it out, and those were the answers I could come up with, and I am not sure if they are correct. The assignment is due tomorrow.
Thanks in Advance.
1. How is the phase transfer catalyst removed from the product?
To remove the phase transfer catalyst from the product in a phase catalysis lab experiment, typically the product is washed with a suitable solvent or solution. The choice of solvent or solution depends on the properties and solubility of the catalyst. In your case, you suggested washing it with salt, which is not a typical method for removing a phase transfer catalyst. Phase transfer catalysts are usually soluble in organic solvents, so a common approach is to repeatedly wash the product with an organic solvent (such as diethyl ether or dichloromethane) to extract and remove the catalyst from the product. This is done by mixing the product with the organic solvent, allowing the catalyst to dissolve in the solvent, and then separating the solvent (containing the catalyst) from the product.
2. What purpose does washing with 15% (half-saturated) NaCl solution serve?
Washing the product with a 15% (half-saturated) NaCl solution serves to remove any remaining water that may be present in the product. Water can interfere with subsequent reactions or affect the purity of the product. By washing with a NaCl solution, the water molecules can be drawn out of the product and dissolved into the solution, leaving behind a relatively water-free product. The use of NaCl in the solution helps to increase the solubility of water, allowing it to be removed more effectively.
3. There is a slight excess of sodium benzoate in the reaction. How is it removed from the product?
To remove the excess sodium benzoate from the product, boiling the reaction mixture is not a typical method. Sodium benzoate is typically a solid or highly soluble in water. Therefore, a more common approach would be to perform a liquid-liquid extraction using an appropriate solvent that does not dissolve the product or the desired components of the mixture, but does dissolve the sodium benzoate. After the extraction, the solvent containing the sodium benzoate can be separated from the product by decantation or filtration.
4. Why is the benzoate anion a stronger nucleophile in 1-bromobutane than in water solution?
In 1-bromobutane, the benzoate anion is a stronger nucleophile compared to a water solution. This is because the benzoate anion is a stronger nucleophile when it is in a non-polar or aprotic solvent like 1-bromobutane. In water, the solvent molecules surround and solvate the benzoate anion, making it less accessible for nucleophilic reactions. However, in 1-bromobutane, which is a non-polar or aprotic solvent, the solvent molecules do not solvate the benzoate anion as effectively. This allows the benzoate anion to retain its nucleophilic properties and react more readily with electrophilic substrates like 1-bromobutane.