Process conditions of synthesis ionone from citral

Ionone,a kind of rare spices,was synthesized by cyclization of pseudoionone that was synthesized from citral.The factors were investigated affecting the synthesis of ionone including the reaction temperature,catalyst amount,reaction time and material ratio.The optimal technological conditions for synthesis of pseudoionone from citral were the mole ratio of citral and acetone 1∶6with 3%sodium hydroxide,then reacting for 4hat 40~45℃,the yield of pseudoionone reached 90.6%.The optimal technological conditions for synthesis of ionone from pseudoionone were the mole ratio of pseudoionone to 85% phosphoric acid 1∶3,then reacting for 2hat 50 ℃,the yield of ionone reached 89.8%,and the total yield of the two-step was 81.4%.