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Plastics, fibers and rubber are three mainstream synthetic materials that are essential to our daily lives and contribute significantly to the quality of our lives. The production of the monomers of these synthetic polymers usually involves oxidation or ammoximation reactions of olefins and analogues. However, the utilization of C, O and N atoms in current industrial processes is <80%, which represents the most environmentally polluting processes for the production of basic chemicals. Through innovation and integration of catalytic materials, new reaction pathways, and reaction engineering, the Research Institute of Petroleum Processing, Sinopec Co. Ltd. (RIPP) and its collaborators have developed unique H2O2-centered oxidation/ammoximation technologies for olefins and analogues, which has resulted in a ¥500 billion emerging industry and driven trillions of ¥s' worth of downstream industries. The chemical and engineering bases of the production technologies mainly involve the integration of slurry-bed reactors and microsphere catalysts to enhance H2O2 production, H2O2 propylene/chloropropylene epoxidation for the production of propylene oxide/epichlorohydrin, and integration of H2O2 cyclohexanone ammoximation and membrane separation to innovate the caprolactam production process. This review briefly summarizes the whole process from the acquisition of scientific knowledge to the formation of an industrial production technology by RIPP. Moreover, the scientific frontiers of H2O2 production and related oxidation/ammoximation processes of olefins and analogues are reviewed, and new technological growth points are envisaged, with the aim of maintaining China's standing as a leader in the development of the science and technologies of H2O2 production and utilization. [ABSTRACT FROM AUTHOR]

By utilizing greenhouse gas CO2 and renewable energy-sourced H2 to produce methanol, the "methanol economy" can replace fossil fuels and H2 as the energy storage medium, which not only reduces CO2 emissions, but also mitigates the energy shortage issue. However, the traditional Cu-based catalysts for CO2-to-methanol conversion suffer from low activity at low temperature and high vulnerability to sintering and deactivation. In this contribution, rapidly quenched skeletal Cu catalysts (RQ Cu) are prepared by leaching the RQ Cu–Al alloy with NaOH aqueous solutions of different concentrations. It is found that high NaOH concentration of 10 wt% favors the preparation of the RQ Cu-10 catalyst with higher porosity, lower residual Al content, and larger active Cu surface area (SCu) than the RQ Cu-3 catalyst leached with 3 wt% of NaOH solution. However, in aqueous-phase CO2 hydrogenation at 473 K and 4.0 MPa, the CO2 conversion over the RQ Cu-3 catalyst is more than two times greater than that over the RQ Cu-10 catalyst, and the selectivity and productivity of methanol are 1.20 and 2.69 times of the corresponding values over the RQ Cu-10 catalyst. At 5.0 MPa, the selectivity and productivity of methanol are further boosted to 97.9% and 1.329 mmol gCu–1 h–1 on the RQ Cu-3 catalyst. It is identified that the SCu of the RQ Cu-3 catalyst is well preserved after reaction, while dramatic growth of the Cu crystallites occurs for the RQ Cu-10 catalyst. The better catalytic performance and stability of the RQ Cu-3 catalyst are tentatively attributed to the presence of more residual Al species by using NaOH solution with lower concentration for Al leaching, which acts as the dispersant for the Cu crystallites during the reaction. [ABSTRACT FROM AUTHOR]

The exfoliation of bulk C3N4 (BCN) into ultrathin layered structure is an effective strategy to boost photocatalytic efficiency by exposing interior active sites and accelerating charge separation and transportation. Herein, we report a novel nitrate anion intercalation‐decomposition (NID) strategy that is effective in peeling off BCN into few‐layer C3N4 (fl‐CN) with tailored thickness down to bi‐layer. This strategy only involves hydrothermal treatment of BCN in diluted HNO3 aqueous solution, followed by pyrolysis at various temperatures. The decomposition of the nitrate anions not only exfoliates BCN and changes the band structure, but also incorporates oxygen species onto fl‐CN, which is conducive to O2 adsorption and hence relevant chemical processes. In photocatalytic O2 reduction under visible light irradiation, the H2O2 production rate over the optimal fl‐CN‐530 catalyst is 952 μmol g−1 h−1, which is 8.8 times that over BCN. More importantly, under full arc irradiation and in the absence of hole scavenger, CH4 can be photocatalytically oxidized by on‐site formed H2O2 and active oxygen species to generate value‐added C1 oxygenates with high selectivity of 99.2 % and record‐high production rate of 1893 μmol g−1 h−1 among the metal‐free C3N4‐based photocatalysts. [ABSTRACT FROM AUTHOR]

The effect of K on the distribution and productivity of the olefins in CO2 hydrogenation over the single‐walled carbon nanotubes (SWNTs) supported Fe catalysts was systematically investigated. The promotion of K not only effectively suppressed the formation of the undesired light paraffins (CH4 and C20−C40), but also significantly affected the distribution and the productivity of the olefins. The highest selectivity and productivity of light olefins (C2=−C4=) of 27 % and 16 μmolCO2 gFe−1 s−1, respectively, were obtained at 7 wt% of K, while the highest selectivity and productivity of heavy olefins (C5+=) of 40 % and 27 μmolCO2 gFe−1 s−1, respectively, were obtained at 3 wt% of K under the same reaction conditions. At 3 wt% of K and above, the overall selectivity to the olefins (inclusive of light olefins and heavy olefins) remained at as high as ca. 60 % at high CO2 conversion of ca. 50 %. Comprehensive characterizations revealed that the K promoter enhanced the basicity of the catalyst, which facilitates the formation of χ‐Fe5C2, the key active phase for CO2 hydrogenation. A good linear relationship is established between the surface basicity and the content of χ‐Fe5C2. Moreover, the K promoter weakened the adsorption of the olefins, which inhibited the secondary hydrogenation of the olefins, thus improving the selectivity to the olefins. This work demonstrates that K is a highly promising promoter for the tailoring of the types of the olefinic products in CO2 hydrogenation. [ABSTRACT FROM AUTHOR]