oa Amidoximes: Promising Candidates for CO2 Capture

Amidoximes are an important class of organic compounds featuring a fused amide and oxime functionality and their use as starting materials for the synthesis of valuable heterocyclics and related intermediates enabled wide applications in novel pharmaceuticals, antitumor agents, antimalarial agents, nitric oxide synthase (NOS) substrates, enhanced textile materials, synthetic polymers, and chelating resins. In this work, amidoxime functionality dependent CO2 adsorption behavior is presented. It is showed that amidoxime groups offer new chemical terminals for selective CO2 binding and such previously unknown behavior puts this well-known class of organic building blocks into spotlight for the pursuit of commercial scale CO2 capture and storage. In an attempt to quantify their performance, four representative amidoximes with varying amidoxime content were screened by using high-pressure magnetic suspension sorption apparatus. The highest percent amidoxime functionality present in acetamidoxime was found to show the highest capacity with 2.71 mmol/g. Acetamidoxime also featured a dimerization, which leads to an enhanced adsorption with an increase in temperature. Moreover, polymeric amidoxime showed superior adsorption per surface area when compared to a well-known activated carbon.