Development of Amino-Functionalized Silica by Co-condensation and Alkylation for Direct Air Capture.

CO chemisorption using amine-based sorbents is one of the most effective techniques for carbon capture and storage. Solid CO sorbents with amines immobilized on their surface have been attracting attention due to the easy collection of sorbents and reusability. In this study, we developed a solid CO adsorbent by co-condensation of a silanizing reagent having a chloroalkyl group and tetraethyl ethoxysilane, followed by alkylation of the chloroalkyl group with diamine.

QXAFS study of CO and H adsorption on Pt in [PtAu(PPh)]-H[PMoO] solid.

The adsorption behaviors of H and CO molecules in crown-motif [PtAu(PPh)]-H[PMoO] (PtAu8-PMo12) solids were investigated by quick-scan X-ray absorption fine structure (QXAFS) measurements with a time resolution of 0.1 s. The electronic state of Pt in PtAu8-PMo12 was drastically changed by the adsorption of H and CO molecules because of the formation of Pt-H/Pt-CO interactions.

Chiral spherical aromatic amides: one-step synthesis and their stereochemical/chiroptical properties.

Macrocyclic aromatic amides 2, in which the -positions of all four benzene rings are linked by tertiary amide bonds, were successfully synthesized by a one-step condensation reaction of two monomers using dichlorotriphenylphosphorane or triphenylphosphine/hexachloroethane (dehydration-condensation reagents for carboxy and amino groups), or LiHMDS (aminolysis for esters) as coupling reagents. Single crystal X-ray analyses of the -methyl and -ethyl derivatives were performed and revealed that each compound adopted a spherical structure with chirality because of the fixed axis rotation and combined polarity of the amide bonds. Enantiomers of each spherical macrocycle were separated by chiral column chromatography and showed mirror-imaged CD spectra to each other.

Low-Temperature Desorption of CO from Carbamic Acid for CO Condensation by Direct Air Capture.

The high temperature requirement for the desorption of absorbed CO is one of the issues for the widespread use of direct air capture (DAC), which is a promising technology to reduce atmospheric CO concentration. This work realized a liquid diamine absorbent-solid carbamic acid (CA) phase-change DAC system with CO desorption at a low temperature by using a MeOH solvent. The CA of isophoronediamine [3-(aminomethyl)-3,5,5-trimethylcyclohexylamine, CA-IPDA] readily desorbed CO in MeOH at 50 °C, while IPDA showed the capacity to absorb low-concentration CO from air with an IPDA/CO ratio of 1:1.