反应详情

At 135° C., 122 g of 4-hydroxybenzaldehyde, 163 g of propionic anhydride and 112 g of potassium propionate were reacted with stirring for 30 hours, the reaction mixture was dropped into 1.5 l of distilled water, and sodium carbonate was added to form an aqueous alkaline solution. The unreacted 4-hydroxybenzaldehyde was removed and concentrated hydrochloric acid was added to render the solution acidic and precipitate the reaction product. The precipitate was recovered by filtration and washed with water to obtain 85 g of a crude product. The precipitate was dissolved in a solution comprising 150 g of water, 150 g of ethanol and 30 g of sodium hydroxide, and the solution was refluxed for 2 hours and dropped into a liquid comprising concentrated hydrochloric acid and ice to precipitate the reaction product. The precipitate was recovered by filtration, washed repeatedly with distilled water and dried to obtain 61 g of crude 4-hydroxy-α-methylcinnamic acid. A product (refined 4-hydroxy-α-methylcinnamic acid) obtained by recrystallizing this crude 4-hydroxy-αmethylcinnamic acid from hot water was used for the subsequent reaction.

1. additionwas added
2. customto form an aqueous alkaline solution
3. customThe unreacted 4-hydroxybenzaldehyde was removed
4. additionconcentrated hydrochloric acid was added
5. customprecipitate the reaction product
6. filtrationThe precipitate was recovered by filtration
7. washwashed with water
8. customto obtain 85 g of a crude product
9. dissolutionThe precipitate was dissolved in a solution
10. temperaturethe solution was refluxed for 2 hours
11. customto precipitate the reaction product
12. filtrationThe precipitate was recovered by filtration
13. washwashed repeatedly with distilled water
14. customdried