Direct alkenylation of aromatics with phenylacetylene over supported H3PW12O40 catalysts as a clean and highly efficient approach to producing α-arylstyrenes

• Published in: Journal of catalysis Vol. 288; pp. 44 - 53
• Main Authors: Zhao, Zhongkui, Dai, Yitao, Bao, Ting, Li, Renzhi, Wang, Guiru
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.04.2012; Elsevier
• Subjects: Alkenylation; ammonia; benzene; Catalysis; catalysts; catalytic activity; Chemistry; Clean synthesis; Colloidal state and disperse state; desorption; Exact sciences and technology; Fourier transform infrared spectroscopy; General and physical chemistry; heat; Heterogeneous catalysis; Impregnation methods; Ion-exchange; nitrogen; phosphotungstic acid; Phosphotungstic acids; Porous materials; streams; Surface physical chemistry; temperature; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; X-ray diffraction; zeolites; Zeolites: preparations and properties; α-Arylstyrenes; Heterogeneous catalysis; Clean synthesis; Impregnation methods; Phosphotungstic acids; Alkenylation; α-Arylstyrenes; Acetylenic compound; Acidic site; Porous material; Molecular sieve; Supported catalyst; Characterization; Synthesis; Structure; Catalyst support; Catalytic reaction; Deactivation; Stability; Thermodesorption; Desorption; Zeolite; Conversion; X ray diffraction; Coke deposition; Mesoporosity; Infrared spectrometry; Ammonia; Impregnation; Acids; Adsorption; Heating; Benzene; Reaction time; Benzenic compound
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2011.12.024

Direct alkenylation of aromatics with phenylacetylene over the novel solid acid catalyst H3PW12O40/MCM-41 has presented a green and highly efficient synthesis protocol for α-arylstyrenes, and the catalytic performance is remarkably better than that on HY zeolite. [Display omitted] ► H3PW12O40/MCM-41 is a highly efficient catalyst for direct alkenylation of aromatics. ► Developed catalyst shows superior catalytic properties in alkenylation in comparison with HY. ► Catalytic properties strongly depend on dispersity, acid sites and maintaining Keggin structure. ► PTA loading and calcination temperature remarkably affect catalyst nature. ► The article presents a green and highly efficient protocol for producing various α-arylstyrenes. Phosphotungstic acid (PTA) catalysts supported on MCM-41 prepared via a wet impregnation method assisted by vacuum with heating (IMPVH) were first employed for direct alkenylation of different aromatics with phenylacetylene to synthesize α-arylstyrenes. N2 adsorption–desorption, FT-IR, X-ray diffraction (XRD), and NH3 temperature-programmed desorption (NH3 TPD) characterization techniques were used to reveal the relationship between the catalyst’s nature and properties. The results demonstrate that the fabricated 25wt.% PTA/MCM-41 catalyst exhibits outstanding catalytic performance, remarkably better than that on HY zeolite. It is also found that the catalytic properties of the catalysts are strongly dependent on PTA dispersity, the nature of the acid sites, the preservability of PTA Keggin structure, and the mesopore architecture, notably affected by PTA loading and calcination temperature. The results for catalytic stability illustrate that more than 99% of maximum conversion can be obtained, and more than 92% conversion can be maintained for up to 540min time on stream. We find that the decrease in catalytic activity, along with the long reaction time, is mainly ascribable to deactivation by coke deposition. The spent catalyst can be refreshed, and 97.1% conversion can be obtained over the regenerated catalyst. This approach is also highly efficient for extra-substituted benzene, polycyclic aromatics, and even heteroaromatics, suggesting that the method presented in this paper can be a green and highly efficient synthesis protocol for α-arylstyrenes.