甲醛和丙醛Mannich缩合制备甲基丙烯醛

甲基丙烯醛（MAL）作为一种重要的有机合成中间体，在医药农药、香精香料、工业助剂、水泥减水剂等领域应用非常广泛。甲醛和丙醛Mannich缩合法合成MAL具有反应条件温和、操作简单、副产物少等优点。本文概述了MAL的工业应用、Mannich缩合反应机理，着重阐述了甲醛和丙醛的Mannich缩合催化剂及反应工艺的研究进展。文中指出，目前Mannich缩合制MAL采用的均相催化体系及工艺，催化剂用量大且难以分离和循环利用，环境污染严重，成本较高；多相催化体系的应用解决了催化剂的分离和重复利用问题，但目前催化剂活性和选择性较低。因此，未来的研究应该重点关注：①开发高效的新型均相催化剂以及相应的连续反应工艺，降低催化剂用量；②开发高性能的多相催化剂，提高催化剂的活性和选择性。

Synthesis of methacrolein (MAL) via Mannich condensation of formaldehyde and propionaldehyde

Methacrolein (MAL) is an important organic synthesis intermediate, which shows a broad application prospect in pharmaceuticals and pesticides, flavors and fragrances, industrial additives and cement water-reducing agent. Mannich condensation of propionaldehyde and formaldehyde to MAL could be operated under mild conditions and produce minor byproducts. In this review, the industrial application of MAL, the reaction mechanism of Mannich condensation, and in particular, the recent progress in the catalysts and the reaction process for Mannich condensation of formaldehyde and propionaldehyde are expounded. Researches have suggested that there are some problems in current homogeneous synthesis of MAL via Mannich condensation, such as the overuse and the difficult separation and recycle of the catalysts, serious pollution, high cost. On the other hand, with the application of heterogeneous catalysts, problems like separation, recycling and reusage of catalysts could be easily solved. However, the activity and selectivity of current heterogeneous catalysts remain relatively low. Therefore, future research should focus on: ①Developing new efficient homogeneous catalyst and corresponding continuous reaction process to reduce the dosage of catalyst; ②Developing high-performance heterogeneous catalysts with improved activity and selectivity.