Aromatic aldehydes and anhydrides can react like aldol condensation in the presence of basic catalysts. The formation of α, β unsaturated aromatic acids is called Perkin reaction. The catalyst is usually potassium or sodium carboxylate of corresponding anhydride, and sometimes K2CO3 or tertiary amine can be used instead. A typical example is the preparation of cinnamic acid.      

    The role of base is to capture the α hydrogen atom of anhydride, so that the α carbon atom becomes a carbon anion. Then the carbon anion and the carbonyl carbon atom on the aromatic aldehyde undergo nucleophilic addition, and then undergo β elimination reaction to produce cinnamate.

    After the reaction is completed, the operation method and skill of separating the product from the mother liquor system. Benzaldehyde has a strong pungent smell. Special attention should be paid to sealing in the use and disposal to strictly control the amount of volatilization.  

    According to the method proposed by kalnin, anhydrous K2CO3 is used to replace ch3cook, which has the advantages of short reaction time and high yield.

    Steam distillation is to introduce water vapor into organic substances that are insoluble or insoluble in water but have certain volatility, so that the organic substances are less than   100  It is distilled with steam at a temperature of ℃.

    productcinnamic acidIt is an important intermediate for the production of "xinkean", a drug for coronary heart disease. Its ester derivatives are important raw materials for the preparation of flavors and food fragrances. It is also widely used in the production of fine chemical products such as agricultural plastics and photosensitive resins.