Synergistic Hydrothermal Conversion of Aqueous Solutions of CO2 and Biomass Waste Liquefaction into Formate

CO₂ utilization by conversion into useful chemicals can contribute to facing the problem of increasing CO₂ emissions. Among other alternatives, hydrothermal transformation stands out by the high conversions achieved, just using high-temperature water as the solvent. Previous works have demonstrated that several organic compounds with hydroxyl groups derived from biomass can be used as reductants of NaHCO₃ aqueous solutions as inorganic CO₂ sources. Formate was obtained as the main product as it was produced by conversion both of the inorganic carbon and of the organic reductants, whose transformation into formate was promoted by the addition of NaHCO₃. Based on these results, in this work, the hydrothermal conversion of NaHCO₃ is performed together with the liquefaction of lignocellulosic biomass (sugarcane bagasse and pine needles) in a one-pot process. Results show that yields to formate of 10% wt/wt (with respect to the initial concentration of biomass) are achieved by hydrothermal treatment of NaHCO₃ and lignocellulosic biomass at 250 °C with a residence time of 180 min. Other products, such as acetic acid and lactic acid, were also obtained. These results demonstrate the feasibility of the hydrothermal reduction of CO₂ combined with the hydrothermal liquefaction of residual biomass in a simultaneous process.

Sensitive and Facile HCOOH Fluorescence Sensor Based on Highly Active Ir Complexes’ Catalytic Transfer Hydrogen Reaction

With several major polarity and weak optical properties, the sensitive detection of HCOOH remains a major challenge. Given the special role of HCOOH in assisting in the catalytic hydrogenation process of Ir complexes, HCOOH (as a hydrogen source) could rapidly activate Ir complexes as catalysts and further reduce the substrates. This work developed a facile and sensitive HCOOH fluorescence sensor utilizing an optimal catalytic fluorescence generation system, which consists of the phenyl-pyrazole-type Ir-complex PP-Ir-Cl and the coumarin-type fluorescence probe P-coumarin. The sensor demonstrates excellent sensitivity and specificity for HCOOH and formates; the limits of detection for HCOOH, HCOONa, and HCOOEt₃N were tested to be 50.6 ppb, 68.0 ppb, and 146.0 ppb, respectively. Compared to previous methods, the proposed sensor exhibits good detection accuracy and excellent sensitivity. Therefore, the proposed HCOOH sensor could be used as a new detection method for HCOOH and could provide a new design path for other sensors.

Silyl formates as hydrosilane surrogates for the transfer hydrosilylation of ketones

A transfer hydrosilylation of ketones employing silyl formates as hydrosilane surrogates under mild conditions is presented. A total of 24 examples of ketones have been successfully converted to their corresponding silyl ethers with 61-99% yields in the presence of a PN^HP-based ruthenium catalyst and silyl formate reagent. The crucial role of the ligand for the transformation is demonstrated.