超声空化合成安息香

采用超声空化、相转移催化法,用水/乙醇为反应介质,以苯甲醛为原料,盐酸硫胺（VB1）为催化剂,在碱性溶液中反应制得安息香。对原料配比、反应温度、反应时间、体系pH值、相转移催化剂的种类等各种反应条件的影响作了详细的研究。实验得到最优条件为：乙醇/水二元混合溶液中,苯甲醛5 mL,盐酸硫胺2.0 g,相转移催化剂用量占苯甲醛质量的百分比为10%~12%,蒸馏水量2 mL,乙醇量8 mL,体系的pH值控制在9.3~9.7之间,水浴超声空化控温在70℃左右,反应时间90 min,超声功率80%。最优条件下收率达到93.57%,产品含量在90%以上。该工艺具有反应条件温和、转化率较高等优点。

Preparation of Benzoin Under Ultrasonic Condition

Use the water/ethanol as the reaction medium, benzaldehyde as raw material, thiamine hydrochloride （VB1） as catalyst,benzoin was prepared in alkaline solution by ultrasonic cavitation and phase transfer catalysis. The effects of various reaction conditions, such as ratio of raw materials, reaction temperature, reaction time, system pH, the type of phase transfer catalyst,were studied in detail.The best conditions were in ethanol / water mixed solution,the amount of benzaldehyde was 5 mL ,the catalyst thiamine hydrochloride was 2.0 g, the quality of phase transfer catalyst was 10% - 12% of benzaldehyde ,the volume of disti Ued water was 2 mL, ethanol was 8 mL,the system pH was 9.3-9.7,reaction temperature was about 70 ℃ ,the reaction time was 90 minutes, the ultrasonic frequency was 80%.The yield reached 97.32%, the product content was 90%.The process had the advantagements,such as mild reaction condition and higher conversion rate etc.