Abstract
The hydroformylation of alkenes with CO and H2 to manufacture aldehydes is one of the most large-scale chemical reactions. However, an efficient and recyclable heterogeneous catalyst for alkene hydroformylation is extremely in demand in academia and industry. In this study, a sulfated carbon nitride supported rhodium particle catalyst (Rh/S-g-C3N4) was successfully synthesized via an impregnation-borohydride reduction method and applied in the hydroformylation of alkenes. The catalysts were characterized by XRD, FTIR, SEM, TEM, XPS, and nitrogen adsorption. The influence of the sulfate content, pressure of syngas, temperature, and reaction time, as well as the stability of Rh/S-g-C3N4, on the hydroformylation was examined in detail. The delocalized conjugated structure in g-C3N4 can lead to the formation of electron-deficient aromatic intermediates with alkenes. The sulphate g-C3N4 has a defected surface owing to the formation of oxygen vacancies, which increased the adsorption and dispersion of RhNPs on the surface of g-C3N4. Therefore, Rh/S-g-C3N4 exhibited an outstanding catalytic performance for styrene hydroformylation (TOF = 9000 h−1), the conversion of styrene could reach 99.9%, and the regioselectivity for the branched aldehyde was 52% under the optimized reaction conditions. The catalytic properties of Rh/S-g-C3N4 were also studied in the hydroformylation of various alkenes and displayed an excellent catalytic performance. Furthermore, the reuse of Rh/S-g-C3N4 was tested for five recycling processes, without an obvious decrease in the activity and selectivity under the optimum reaction conditions. These findings demonstrated that Rh/S-g-C3N4 is a potential catalyst for heterogeneous hydroformylation.
Highlights
Hydroformylation has been extensively applied in industry to manufacture aldehydes by the addition of CO and H2 to alkenes in one step with a 100% atom efficiency [1,2,3]
We investigate the effect of sulfate on improving the deposition of Rh particles on g-C3 N4 and enhancing the catalytic performance of Rh/g-C3 N4 in the hydroformylation of alkenes
In this study, sulphated g-C3 N4 supported rhodium particle catalysts were synthesized via an impregnation-borohydride reduction method and exhibited outstanding catalytic performances for styrene hydroformylation (TOF = 9000 h−1 ), due to the delocalized conjugated π structure of g-C3 N4, which can form electron-deficient aromatic intermediates with alkenes
Summary
Hydroformylation (oxo process) has been extensively applied in industry to manufacture aldehydes by the addition of CO and H2 to alkenes in one step with a 100% atom efficiency [1,2,3]. The aldehydes formed are valuable industrial products and intermediates in the synthesis of bulk chemicals, such as alcohols, carboxylic acids, esters, amines, and so on [4,5]. This green and clean synthetic route was accidentally found by Otto Roelen during the Fischer-Tropsch process in 1938 [6]. Today, this transformation represents one of the most large-scale reactions in industry. More than ten million tons of “oxo chemicals” are manufactured by the hydroformylation reaction [7,8].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
