1. In a 100 mL glass reaction flask, 940.5 mg of phenol and 2.80 g of hexamethylenetetramine were accurately weighed, 30 mL of trifluoroacetic acid was added, and a magnetic stirrer was placed.
2. The reaction was heated to reflux using a magnetic stirring temperature-controlled electric heating jacket, and the reaction process was monitored by thin-layer chromatography (TLC) during the reaction, and the heating was stopped after about 6 hours of reaction.
3. Upon completion of the reaction, the reaction mixture was cooled to room temperature and then slowly poured into a 100 mL beaker pre-filled with 50 mL of distilled water and stirred thoroughly.
4. Transfer the mixture to a separatory funnel, add 20 mL of dichloromethane, seal and shake vigorously several times, and leave to stratify.
5. Since methylene chloride is denser than water, the organic layer is in the lower layer. Open the piston of the separatory funnel and collect the lower layer of methylene chloride solution.
6. Repeat the extraction step 3 to 5 times, using 20 mL of dichloromethane each time, to ensure that the product is completely transferred to the organic phase.
7. Combine the organic phases and transfer to a 25 mL glass reaction flask and remove the solvent using a rotary evaporator to obtain the crude product.
8. A small amount of the crude product was dissolved in dichloromethane and subjected to Thin Layer Chromatography (TLC), using dichloromethane as the unfolding agent, and the spots were observed under UV light to confirm the purity of the product.
9. The final product was 976.5 mg in 65.1% yield, which can be used directly in the subsequent reaction.
