3-羟基-2-丁酮合成2,3,5,6-四甲基吡嗪的研究

Study on Synthesis of 2,3,5,6-tetramethylpyrazine with 3-hydroxy-2-butanone

对利用3-羟基-2-丁酮合成2,3,5,6-四甲基吡嗪的过程进行了研究,考察了不同反应温度、时间、真空度、3-羟基-2-丁酮与铵盐物质的量比和pH值的影响规律。结果表明:3-羟基-2-丁酮、乙酸铵物质的量比在1∶1.4,pH值为6,反应初期温度40℃,反应时间1h,后期温度90℃,真空度(绝对压力)3000Pa,反应时间控制在2h时,2,3,5,6-四甲基吡嗪总收率可达到87.5%以上。

Research of synthesis of 2, 3, 5, 6-tetramethylpyrazine by 3-hydroxy-2-butanone are investigated.Effects on 3-hydroxy-2-butanone,ammonium acetate molar ratio,reactive temperature,reactive pressure,reactive time,pH value,vacuum degree are studied.It is manifested that 3-hydroxy-2-butanone, ammonium acetate molar ratio should be controlled at the Level of 1∶1.4,pH value is 6,the initial reaction temperature should be controlled at 40 ℃,reaction time is about 1 h,the upper reaction temperature should be controlled at 90 ℃,vacuum degree is at 3 000 Pa（absolute pressure）,reaction time is about 2 h,the total yields of 2,3,5,6-tetramethylpyrazine can achieve over than 87.5%.