1. benzaldehyde, perkin reaction, to determine the optimal reaction conditions: n (benzaldehyde): n (acetic anhydride): n (anhydrous potassium carbonate): n (PEG-400): n (p-tert-butyl catechol) = 1:3:1:0.02:0.01, reflux temperature of 180 ℃, the reflux time of 1.5h, the cinnamic acid yield up to 78.7%.

2. Because the neutralization must make the solution alkaline, control pH = 8 is more appropriate, because the alkalinity of sodium hydroxide is too strong, and the amount of addition is not easy to control, and easy will be the occurrence of the Cannicharo reaction. Adding too much sodium hydroxide will cause the cinnamic acid to neutralize to form sodium cinnamate which is soluble in water, thus not allowing the cinnamic acid solid to precipitate.

Hydrodistillation removes the aldehyde that does not participate in the reaction. If you don't use water vapor distillation, you can use decompression distillation to evaporate benzaldehyde.