Blankenship Andrea N, Ravi Manoj, Newton Mark A, van Bokhoven Jeroen A
Institute for Chemical and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 1, 8093, Zurich, Switzerland.
Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institute, 5232, Villigen, Switzerland.
Angew Chem Int Ed Engl. 2021 Aug 9;60(33):18138-18143. doi: 10.1002/anie.202104153. Epub 2021 Jul 5.
A promising strategy to break through the selectivity-conversion limit of direct methane conversion to achieve high yields is the protection of methanol via esterification to a more stable methyl ester. We present an aerobic methane-to-methyl-ester approach that utilizes a highly dispersed, cobalt-containing solid catalyst, along with significantly more favorable reaction conditions compared to existing homogeneously-catalyzed approaches (e.g. diluted acid, O oxidant, moderate temperature and pressure). The trifluoroacetic acid medium is diluted (<25 wt %) with an inert fluorous co-solvent that can be recovered after the separation of the methyl trifluoroacetate via liquid-liquid extraction at ambient conditions. Silica-supported cobalt catalysts are highly active in this system, with competitive yields and turnovers in comparison to known aerobic transition metal-based catalytic systems.
突破直接甲烷转化的选择性-转化率限制以实现高收率的一种有前景的策略是通过酯化将甲醇转化为更稳定的甲酯来进行保护。我们提出了一种有氧甲烷制甲酯的方法，该方法使用高度分散的含钴固体催化剂，并且与现有的均相催化方法（例如稀酸、O 氧化剂、适度的温度和压力）相比，反应条件要优越得多。三氟乙酸介质用惰性含氟共溶剂稀释（<25 wt%），该共溶剂可在室温条件下通过液-液萃取分离三氟乙酸甲酯后回收。二氧化硅负载的钴催化剂在该体系中具有高活性，与已知的有氧过渡金属基催化体系相比，产率和周转率具有竞争力。
