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1,4-dioxane is a potential carcinogen in water and is difficult to deal with due to its robust cycloether bond and complete miscibility with water. To remove 1,4-dioxane in an economically viable and environmentally friendly way, a series of carbon aerogels were synthesized as adsorbents for 1,4-dioxane. The experiment results showed that adsorption performances were closely related to the preparation conditions of carbon aerogels, such as the molar ratio, heating rate, pyrolysis temperature and residence time, which were carefully controlled. Scanning electron microscope analysis revealed the presence of a three-dimensional porous network structure in carbon aerogels. Brunauer–Emmett–Teller analysis results demonstrated an increase in specific surface area (673.89 m2/g) and total pore volume after carbonization, with an increase in mesoporous porosity and a decrease in microporosity. When considering each variable individually, the highest specific surface area of prepared carbon aerogels was achieved at a pyrolysis temperature of 800 °C, a holding time of 1 h, and a heating rate of 2 °C/min. Under optimal experimental conditions, the adsorption removal of 1,4-dioxane by carbon aerogels exceeded 95%, following quasi-second-order kinetics and Langmuir isothermal adsorption isotherms, indicating that monolayer adsorption on the surface of carbon aerogels occurred. The maximum adsorption capacity obtained was 67.28 mg/g at a temperature of 318 K, which was attributed to the presence of a large proportion of mesopores and abundant micropores simultaneously in carbon aerogels. Furthermore, with the interference of chlorinated solvents such as trichloroethylene (TCE), the removal efficiency of 1,4-dioxane had no obvious inhibition effect. Regeneration experiments showed that after five continuous cycles, the carbon aerogels still kept a comparable adsorption capacity, which illustrates its potential application in 1,4-dioxane-polluted water purification. [ABSTRACT FROM AUTHOR]

It is still a challenge to construct single-atom level reduction and oxidation sites in single-component photocatalyst by manipulating coordination configuration for photocatalytic water splitting. Herein, the atomically dispersed asymmetric configuration of six-coordinated Co-S 2 O 4 (two exposed S atoms, two OH groups, and two Co─O─Zn bonds) suspending on ZnIn 2 S 4 nanosheets verified by combining experimental analysis with theoretical calculation, is applied into photocatalytic water splitting. The Co-S 2 O 4 site immobilized by Vs acts as oxidation sites to guide electrons transferring to neighboring independent S atom, achieving efficient separation of reduction and oxidation sites. It is worth mentioning that stabilized Co-S 2 O 4 configuration show dynamic structure evolution to highly active Co-S 1 O 4 configuration (one exposed S atom, one OH group, and three Co─O─Zn bonds) in reaction, which lowers energy barrier of transition state for H 2 O activization. Ultimately, the optimized photocatalyst exhibits excellent photocatalytic activity for water splitting (H 2 : 80.13 µmol g -1 h -1 , O 2 : 37.81 µmol g -1 h -1 ) and outstanding stability than that of multicomponent photocatalysts due to dynamic and reversible evolution between stable Co-S 2 O 4 configuration and active Co-S 1 O 4 configuration. This work demonstrates new cognitions on immobilized strategy through vacancy inducing, manipulating coordination configuration, and dynamic evolution mechanism of single-atom level catalytic site in photocatalytic water splitting., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

A new metal-free oxidative decarbonylative [2 + 2 + 2] carbocyclization of N -(2-ethynylaryl)acrylamides with tertiary and secondary alkyl aldehydes is described. This reaction enables the formation of three new C-C bonds in a single reaction by a sequence of oxidative decarbonylation, radical addition across C-C unsaturated bonds, C-H functionalization and annulation, and represents the first oxidative decarbonylative [2 + 2 + 2] carbocyclization approach using tertiary and secondary alkyl aldehydes as a two carbon unit for assembling six-membered carbocycle-fused polycycles.

A copper/silver-catalyzed Conia-ene reaction has been developed for selectively constructing five-membered and six-membered rings. In the presence of (CuOTf)(2) x C(6)H(6) and AgBF(4), a variety of 2-alkynic 1,3-dicarbonyl compounds underwent the Conia-ene intramolecular reaction smoothly in moderate to good yields. It is noteworthy that both 2-phenylacetylhept-6-ynenitrile and diethyl 2-(pent-4-ynyl)malonate are also suitable substrates under the standard conditions, and the selectivity toward endo- or exo-products depends on the substituents at the terminal of alkynes.