Technology optimization of cinnamic acid synthesized by knoevenagal reaction using organic alkali catalyst

Cinnamic acid was synthesized from benzaldehyde and malonic acid as the raw material,and the organic weak-base such as pyridine as the catalyst by Knoevenagel reaction.The main objective of this paper is to improve the synthetic technique of cinnamic acid,reduce the reaction temperature and enhance the yield and purity of the product.Meanwhile,the influence of various weak-base catalysts on yield of cinnamic acid was compared and analyzed. The results indicated that pyridine was the optimal catalyst.Furthermore,in the presence of the organic alkali catalyst,the effects of various technical parameters on the yield of products were investigated by using orthogonal design,and the optimum conditions found for synthesizing cinnamic acid were as follows: pyridine is the optimum catalyst and its amount is 0.02 mol,the molar ratio of benzaldehyde to malonic acid was 1:3,the reaction time was 90min,and the yield reached 90% under these conditions.