Cinnamic acid is a spicy organic compound that can be prepared from cinnamic aldehyde or cinnamyl alcohol. The following are suggestions for improvement of cinnamic acid preparation experiments:

1. Cinnamaldehyde and cinnamyl alcohol can be prepared by using more environmentally friendly solvents, such as ethanol or acetone, instead of organic solvents such as benzene or dichloromethane. This will help reduce the generation of hazardous waste and environmental pollution.

2. Milder reaction conditions can be used, such as boiling water for esterification reaction. This reduces side reactions between reactants and produces fewer by-products.

3. Adding catalysts, such as sulfuric acid, phosphoric acid or ferric chloride, can promote the reaction and accelerate the reaction speed, thus increasing the yield. However, care must be taken not to use excess catalyst, otherwise side reactions and unnecessary waste will occur.

4. During the preparation process, purification methods, such as recrystallization or column chromatography, can be used to reduce impurities and improve purity. This ensures the quality and yield of the final product.

5. During the operation, you should pay attention to safe operation and wear personal protective equipment, such as gloves, goggles, etc. At the same time, reaction conditions are strictly controlled to avoid accidents such as fires and explosions.