Schuler Eric, Stoop Marit, Shiju N Raveendran, Gruter Gert-Jan M
Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1090 GD Amsterdam, The Netherlands.
Avantium Chemicals BV, Zekeringstraat 29, 1014 BV Amsterdam, The Netherlands.
ACS Sustain Chem Eng. 2021 Nov 8;9(44):14777-14788. doi: 10.1021/acssuschemeng.1c04539. Epub 2021 Oct 25.
One of the crucial steps for the conversion of CO into polymers is the catalytic formate to oxalate coupling reaction (FOCR). Formate can be obtained from the (electro)catalytic reduction of CO, while oxalate can be further processed toward building blocks for modern plastics. In its 175 year history, multiple parameters for the FOCR have been suggested to be of importance. Yet, no comprehensive understanding considering all those parameters is available. Hence, we aim to assess the relative impact of all those parameters and deduce the optimal reaction conditions for the FOCR. We follow a systematic two-stage approach in which we first evaluate the most suitable categorical variables of catalyst, potential poisons, and reaction atmospheres. In the second stage, we evaluate the impact of the continuous variables temperature, reaction time, catalyst loading, and active gas removal within previously proposed ranges, using a response surface modeling methodology. We found KOH to be the most suitable catalyst, and it allows yields of up to 93%. Water was found to be the strongest poison, and its efficient removal increased oxalate yields by 35%. The most promising reaction atmosphere is hydrogen, with the added benefit of being equal to the gas produced in the reaction. The temperature has the highest impact on the reaction, followed by reaction time and purge rates. We found no significant impact of catalyst loading on the reaction within the ranges reported previously. This research provides a clear and concise multiparameter optimization of the FOCR and provides insight into the reaction cascade involving the formation and decomposition of oxalates from formate.
将一氧化碳转化为聚合物的关键步骤之一是催化甲酸酯到草酸盐的偶联反应（FOCR）。甲酸酯可通过一氧化碳的（电）催化还原获得，而草酸盐可进一步加工成现代塑料的构建模块。在其175年的历史中，人们提出了多个对FOCR至关重要的参数。然而，目前还没有对所有这些参数进行全面的理解。因此，我们旨在评估所有这些参数的相对影响，并推导出FOCR的最佳反应条件。我们采用了一种系统的两阶段方法，首先评估催化剂、潜在毒物和反应气氛等最合适的分类变量。在第二阶段，我们使用响应面建模方法，在先前提出的范围内评估连续变量温度、反应时间、催化剂负载量和活性气体去除的影响。我们发现氢氧化钾是最合适的催化剂，其产率可达93%。水被发现是最强的毒物，有效去除水可使草酸盐产率提高35%。最有前景的反应气氛是氢气，其额外的好处是与反应中产生的气体相同。温度对反应的影响最大，其次是反应时间和吹扫速率。我们发现在先前报道的范围内，催化剂负载量对反应没有显著影响。这项研究为FOCR提供了清晰简洁的多参数优化，并深入了解了涉及从甲酸酯形成和分解草酸盐的反应级联。
