甲基丙烯醛的合成

Synthesis of Methacrolein

以甲醛、丙醛和含仲胺功能基的330弱碱性环氧系阴离子交换树脂(简称330树脂)为原料,经Mannich反应和Mannich碱热分解反应合成了甲基丙烯醛;考察了反应条件对丙醛转化率和甲基丙烯醛选择性的影响,得到了适宜的反应条件。实验结果表明,在n(丙醛)∶n(甲醛)∶n(330树脂中的仲胺)=1.0∶1.1∶1.0、Mannich反应温度45℃、Mannich反应时间50 min、分解温度75℃、分解时间70 min的反应条件下,丙醛转化率达99.5%、甲基丙烯醛选择性达93.1%。反应完成后,经过滤,330弱碱性环氧系阴离子交换树脂可从反应体系中分离并经稀酸和稀碱再生处理后可循环使用。循环实验结果表明,330树脂循环使用5次后,丙醛转化率变化不大。

Methacrolein （MAL） was synthesized by Mannich reaction of formaldehyde, propionaldehyde and 330 weak alkali epoxy anion exchange resin（330 resin） containing secondary amine functional group and then thermal decomposition reaction of Mannich base. Effects of reaction conditions on the conversion of propionaldehyde and the selectivity to MAL were investigated. The results indicated that the conversion of propionaldehyde and selectivity to MAL could reach 99.5% and 93.1% respectively under the optimal conditions of n （ propionaldehyde ） ： n （ formaldehyde ） ： n （ secondary amine in 330 resin） 1.0 ： 1.1 ： 1.0, Mannich reaction temperature 45 ℃, Mannich reaction time 50 min, decomposition temperature 75 ℃ and decomposition time 70 min. 330 Resin can be easy separated from the reaction system by simple filtration. The recycle experiment results demonstrated that 330 resin could be recycled five times without significant activity loss.