Preparation And Catalytic Performance Of Polypyrrole And Hydrotalcite Supported Catalysts

Supported catalysts have wide applications and important roles in catalytic synthesis and industrial reactions due to their recoverable and efficient performance.In the preparation of catalysts,the stability,large specific surface area,and controllability of the support are often used to improve the active ingredients that are difficult to recover,agglomerate,and difficult to handle.Based on polypyrrole and hydrotalcite,polypyrrole nanowire-supported silver bromide catalyst,polypyrrole nanowiresupported iodine,and hydrotalcite-supported Lewis acid catalyst were prepared.The catalysts were analyzed by infrared spectroscopy,thermogravimetry,scanning electron microscope and so on.The properties of polypyrrole nanowire-supported silver bromide for the degradation of rhodamine B and polypyrrole nanowire-supported iodine were used to synthesize polysubstituted arylimidazoles.The effects of hydrotalcitesupported Lewis acid-catalyzed on the Strecker reaction and preparation of isothiocyanate were also investigated.The following conclusions were reached:?1?Using cetyltrimethyl surfactant as template and silver bromide as a source of bromine,three PPy/Ag Br photocatalysts with different silver bromide contents were prepared by the double-drop method.the prepared photocatalytic material has a network-like polypyrrole active substrate and uniform silver bromide particles.The supported catalysts have better performance than Ag Br in the removal of rhodamine B.Among them,the best catalyst catalytic removal efficiency can reach 93% in 1 h,and the catalytic removal ability can be achieved by recycling three times.?2?A polypyrrole-supported iodine catalyst?PPy/I₂?was prepared using polypyrrole nanowires as a carrier,and imidazole compounds were synthesized using benzaldehyde,ammonium acetate,and benzoyl as reaction models.The solvent used,the amount of catalyst,the volume ratio of raw materials and the reaction time were investigated.Under the best reaction conditions: n-butanol is used as the solvent,the molar ratio of the raw materials of benzoyl,benzaldehyde and ammonium acetate is 1? 1? 1.5,the amount of PPy/I₂ catalytic addition is 15 mol%,and the maximum yield was 93.1% when reflux was 3 h.?3?Hydrotalcite-supported Lewis acid was prepared by the impregnation method.The experiments were performed using LDH/I₂ as a catalyst,benzaldehyde and aniline in methanol solvent,and TMSCN provided a cyanide source to synthesize ?-aminonitrile.After optimizing the reaction conditions,the molar ratio of the raw materials of benzaldehyde,aniline and TMSCN is 1? 1? 1.4,the optimal conditions are obtained: the amount of LDH/I₂ catalyst is 10 mol%,and the reaction is stirred for 10 min in a methanol solvent,and the maximum yield is 98.3%.In addition,the hydrotalcite-supported copper chloride?LDHs/CuCl₂?was used as a catalyst,ethanol was used as a solvent,and ?-aminonitrile derivatives were synthesized by ultrasonic catalysis.The optimal reaction conditions were: at room temperature,the molar ratio of the raw materials of benzaldehyde,aniline and TMSCN is 1? 1? 1.5,ultrasonic reaction for 10 min,under this condition,9 kinds of ?-aminonitrile derivatives can be efficiently synthesized,the highest yield can reach 91.5%.?4?In the experiment,aniline and carbon disulfide were used as reaction templates,and the amount ratios of catalysts,solvents,bases,and substances were investigated to obtain the optimal reaction conditions.In acetonitrile solvents,LDH/FeCl₃ was used as the catalyst,and the ratio of the substance of aniline to carbon disulfide is 1? 5,adding potassium carbonate as a base,and reacting for 3h,the 2,4,6-trimethylisothiocyanate can be efficiently prepared with a yield of 80.1%.Under the optimal reaction conditions,many aromatic amines have good adaptability.