Guipeng Ji

Hierarchically Mesoporous o-Hydroxyazobenzene Polymers: Synthesis and Their Applications in CO2 Capture and Conversion

The synthesis of hierarchically mesoporous polymers with multiple functionalities is challenging. Herein we reported a template-free strategy for synthesis of phenolic azo-polymers with hierarchical porous structures based on diazo-coupling reaction in aqueous solution under mild conditions. The resultant polymers have surface areas up to 593 m(2)  g(-1) with the mesopore ratio of >80 %, and a good ability to complex with metal ions, such as Cu(2+) , Zn(2+) ,Ni(2+) , achieving a metal loading up to 26.24 wt %. Moreover, the polymers complexed with Zn showed excellent performance for catalyzing the reaction of CO2 with epoxide, affording a TOF of 2570 h(-1) in the presence of tetrabutyl ammonium bromide (7.2 mol %). The polymer complexed with Cu could catalyze the oxidation of alcohol with high efficiency.

Fluoro-functionalized polymeric ionic liquids: highly efficient catalysts for CO2 cycloaddition to cyclic carbonates under mild conditions

Fluoro-functionalized polymeric ionic liquids (F-PILs) with imidazolium cations and bromide or chloride anions were designed for cycloaddition reactions of CO2 with epoxides. It was found that the fluorine content in F-PILs significantly influenced the catalytic activity of the catalysts, and F-PIL-Br showed three times higher activity for CO2 reacting with styrene oxide than non-fluorous PIL-Br. Moreover, F-PIL-Br could be extended to catalyse a broad range of reactants under 1 MPa CO2 pressure, producing a series of cyclic carbonates in excellent yields (93–99%). In addition, it showed high stability and easy recyclability.

B(C6F5)3-catalyzed methylation of amines using CO2 as a C1 building block

B(C6F5)3 was proven to be an efficient metal-free catalyst for the methylation of amines using CO2 as a C1 building block in the presence of hydrosilanes under easy-handling conditions. A broad range of N-alkylanilines, dialkylamines and primary anilines all proceeded well under the catalytic conditions.

Mesoporous nitrogen-doped carbons with high nitrogen contents and ultrahigh surface areas: synthesis and applications in catalysis

The development of mesoporous nitrogen-doped carbons (NDCs) with high nitrogen contents and high surface areas from biomass is of significance for many applications, such as oxidation reaction catalysts, electrode materials and so on. Herein we report a simple route to prepare mesoporous NDCs via calcinating the mixture of biomass feedstocks (including glucose, cellulose and lignin) and melamine using eutectic salts of KCl and ZnCl2 as the porogen, and a series of mesoporous NDCs with nitrogen content up to 11.9% and BET specific surface area up to 1800 m2 g−1 were obtained. Served as metal-free catalysts for oxidation of hydrocarbons with tert-butyl hydroperoxide in aqueous phase, the mesoporous NDC with a N content of 11.4% showed the highest efficiency compared to the reported N-doped carbons. Moreover, the as-prepared NDCs were indicated to be an ideal support to immobilize noble nanoparticles (e.g., Pd, Rh, Ru, Pt), producing a series of NDC supported metal nanocatalysts with metal particle size of around 2 nm. This work opens up a new way to prepare mesoporous N-doped carbon materials with tailored properties.

Fluoro-functionalized polymeric N-heterocyclic carbene-zinc complexes: efficient catalyst for formylation and methylation of amines with CO2 as a C1-building block

A fluoro-functionalized polymeric N-heterocyclic carbene (NHC)-Zn complex (F-PNHC-Zn) was designed and synthesized by taking fluorous imidazolium salts as precursors through a two-step alkylation. The resultant F-PNHC-Zn was applied in catalyzing the formylation and methylation of amines using CO2 as a C1 building block in the presence of organosilane, which showed much higher activity than the corresponding non-fluorous PNHC-Zn under identical conditions. N-Methylanilines with both electron-withdrawing and electron-donating groups all could be converted to the corresponding formamides and methylamines in >90% conversion. Quantitative conversion of N-methylaniline was obtained even under very low CO2 pressure (0.05 MPa diluted by N2). Moreover, F-PNHC-Zn was highly stable and easily recyclable for these reactions.

Pyridine-functionalized organic porous polymers: applications in efficient CO2 adsorption and conversion

Pyridine-functionalized porous organic polymers showed excellent CO2 uptake capacity (up to 63 and 171 mg g−1 at 0.1 and 1 bar at 273 K), and performed well as supports for Ru(0) nanoparticles. The resultant CarPy-CMP@Ru served as an efficient catalyst for the formylation of amines with CO2/H2, together with high product yields (89–93%), high stability and easy recyclability.

Reductive amination/cyclization of levulinic acid to pyrrolidones versus pyrrolidines by switching the catalyst from AlCl3 to RuCl3 under mild conditions

Herein the reductive amination/cyclization of levulinic acid using phenylsilane was presented to selectively produce pyrrolidones versus pyrrolidines under mild conditions by switching the catalyst from AlCl3 to RuCl3. Using AlCl3 as the catalyst, pyrrolidones were solely obtained at room temperature, while RuCl3 as the catalyst selectively afforded pyrrolidines in high yields at 45 °C.

Visible-light-driven conversion of CO2 from air to CO using an ionic liquid and a conjugated polymer

A metal-free and highly efficient catalytic system involving a task-specific ionic liquid, [P4444][p-2-O], and a pyrene-based conjugated polymer was developed for direct CO2 capture from air and its further photoreduction to CO under visible light irradiation, affording a CO production rate of 47.37 μmol g−1 h−1 with a selectivity of 98.3%.