The combination of Lewis acids and Lewis bases, currently defined as catalysts and co-catalysts (or promoter) respectively, in the reaction between epoxides and CO₂ to give cyclic carbonates, is discussed, starting from examples in which the Lewis base was used in larger amount with respect to the Lewis acid. In these cases, turnover frequency (TOF) values have been usually calculated taking into account solely the amount of the Lewis acid employed. The occurrence of two distinct reaction pathways, one catalysed by the sole Lewis base and the other one catalysed by the Lewis acid/Lewis base couple, in which the Lewis acid alone does not play a catalytic role, should bring researchers to reconsider the TOF calculation based solely on the amount of Lewis acid, especially when the amount of the Lewis base used is much larger than the Lewis acid. In order to draw a more precise picture of how the use of a Lewis base/Lewis acid co-catalytic system affects the reaction course, we analytically examined a general mechanistic scheme able to model the overall process. For these cases, we propose a simple equation for a better estimation of TOF values and a normalization approach for a more consistent comparison between various catalytic systems.

在环氧化物和CO ₂之间的反应中，路易斯酸和路易斯碱的组合（当前分别定义为催化剂和助催化剂（或促进剂））从其中相对于路易斯酸大量使用路易斯碱的实施例开始讨论形成环状碳酸酯的方法。在这些情况下，通常仅考虑所用路易斯酸的量来计算周转频率（TOF）值。出现两种不同的反应途径，一种由唯一的路易斯碱催化，另一种由路易斯酸/刘易斯碱对催化，其中路易斯酸本身不发挥催化作用，这应该使研究人员重新考虑TOF计算。仅基于路易斯酸的量，特别是当所使用的路易斯碱的量远大于路易斯酸时。为了更准确地了解路易斯碱/路易斯酸助催化体系的使用如何影响反应过程，我们分析性地检查了能够对整个过程进行建模的通用机械方案。对于这些情况，我们提出了一个简单的方程式，以更好地估算TOF值，并提出了一种归一化方法，以使各种催化系统之间的比较更一致。