Appaturi Jimmy Nelson, Ratti Rajni, Phoon Bao Lee, Batagarawa Samaila Muazu, Din Israf Ud, Selvaraj Manickam, Ramalingam Rajabathar Jothi
School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia.
Dalton Trans. 2021 Apr 7;50(13):4445-4469. doi: 10.1039/d1dt00456e. Epub 2021 Mar 15.
One of the most crucial attributes of synthetic organic chemistry is to design organic reactions under the facets of green chemistry for the sustainable production of chemicals. Thus, due to the intensified environmental and safety concern, the need for new technologies for conducting chemical transformation has grown. In this regard, there is enormous interest in the use of heterogeneous catalysts as they generally avoid the generation of waste, require fewer toxic reagents, as well as entail easier separation and recycling of the catalyst. α,β-Unsaturated acids have been widely used in various industrial applications and have been identified as one of the most promising chemicals obtained via the Knoevenagel condensation reaction. This review aims to discuss the most pertinent heterogeneous catalytic systems such as zeolites, mesoporous silica, ionic liquids, metal oxides, and graphitic carbon nitride-based catalysts in the Knoevenagel reaction. Ultimately, this review focuses not only on the catalyst but also provides an overall idea and guide for the preparation of new catalysts with outstanding properties by looking at the chemical and engineering aspects such as the reaction conditions and the mechanisms.
合成有机化学最关键的特性之一是在绿色化学的层面下设计有机反应，以实现化学品的可持续生产。因此，由于环境和安全问题日益受到关注，对进行化学转化的新技术的需求也在增加。在这方面，人们对使用多相催化剂有着浓厚的兴趣，因为它们通常可以避免产生废物，所需的有毒试剂较少，并且催化剂的分离和回收也更容易。α,β-不饱和酸已广泛应用于各种工业领域，并被确定为通过克诺文纳格尔缩合反应获得的最有前景的化学品之一。本综述旨在讨论克诺文纳格尔反应中最相关的多相催化体系，如沸石、介孔二氧化硅、离子液体、金属氧化物和石墨相氮化碳基催化剂。最终，本综述不仅关注催化剂，还通过考察反应条件和机理等化学和工程方面，为制备具有优异性能的新型催化剂提供了总体思路和指导。
