Synthesis for high purity beta ionone

The synthetic method for highly pure beta-irisone from citralincludes folloing two steps: firstly citral rects with acetone in strong alkaline liquid (clasien-Schmidt condensation reaction) to form pseudo irisone, then using concentrated sulfuric acid as cyclizing agent, the pseudo irisone cyclizes into beta-irisone. In present method, the content of beta-irisone is higher than 96%, alpha-irisone less than 1%, even no alpha-irisone exists, the product beta-irisone can be used not only as perfume raw material, but also as an important intermediate product for synthesis of vitamin A.