| Suzuki cross-coupling reaction is one important reaction of the most efficientmethods for the synthesis of biphenyl in organic chemistry. The reaction has becomevery popular in combining drugs, natural products, materitals, etc. Suzukicross-coupling reaction has the merits of wider selection over substrate, mild conditions,small toxicity, easy treatment and high regioselectivity and stereoselectivity, especiallywith effective synthesis biphenyl compounds. Suzuki coupling reaction is the synthesisof the most effective methods combining biphenyl under palladium catalyst. In addition,microwave technology is a kind of technology with good prospect in Suzuki couplingreaction.Mesoporous molecular sieves MCM-41has the uniform adjustable mesoporousaperture and stable skeleton structure, which contributes to the spread of theparticipating molecules, and that, easily modified surface, large specific surface area,high thermal stability and stable machine capability, for these reasons, msoporousmolecular sieves MCM-41has received extensive attention. It is the most potential andthe ideal carrier material of supported catalysts.This thesis mainly researched preparation, characterization of MCM-41supportedpalladium catalysts and Suzuki cross-coupling reaction of catalytic performance undermicrowave condition. And the thesis also researched preparation and characterization ofMCM-41supported copper(Ⅱ) catalyst, it was studied that catalytic performancebetween MCM-41supported palladium catalyst and MCM-41supported copper(Ⅱ)catalyst was researched under different heat conditions.First part: Three MCM-41supported palladium catalysts A, B and C were preparedwith one step method assisted by microwave irradiation technique with differentn(Pd)/n(Si), in the paper, we took palladium chloride as palladium source, cetyltrimethyl ammonium bromide (CTAB) as template agent, tetraethoxysilane (TEOS) assilicon source and mesoporous molecular sieves MCM-41as carrier. By means of X-raydiffraction (XRD), FTIR spectrometer (FT-IR), Nitrogen adsorption analyzer andscanning electron microscope (SEM), the structure of the catalysts were characterized.It turned out that the three catalysts all possessed mesoporous structure, large specificsurface area(741.75～894.68m2g-1) and aperture(3.97～4.61nm). Seccond part: The catalytic performance of three MCM-41supported palladiumcatalysts A, B and C using in Suzuki cross-coupling reaction between bromobenzeneand NaBPh4had been investigated systematacially under microwave irradiationcondition. Influence on reaction of palladium loading, microwave radiation temperature,microwave radiation time, microwave power, catalyst amount, solvent and alkali wasinvestigated respectively. Through the research of palladium loading, MCM-41supported palladium catalyst A had the highest catalytic performance with the leastpalladium loading during three catalysts, and the corresponding biphenyl productionrate was the highest. Catalyst A was choosed as catalyst in the reaction, other conditionsremained consistent, it was concluded that microwave temperature60℃was optimumtemperature in reaction and the production rate was the highest. When microwavereaction time was three hours, the production rate was close to80%. When microwavepower was300W, the production rate was the highest up to45.06%. Catalyst dosage isclose to0.10g advisable. When the volume ratio of ethanol and water was for3to1,the objective product yield was the highest. Contrast sodium carbonate and potassiumcarbonate, reaction was easier to do under the effect of sodium carbonate, the objectiveproduct yield was higher also. According to the above factors influencing on thereaction, the optimum reaction conditions of Suzuki cross-coupling reaction had beenconfirmed under the system.Third part: MCM-41supported copper (Ⅱ)catalyst was prepared with the samemethod, we took copper chloride dehydrate as copper source and mesoporous molecularsieves MCM-41as carrier. By means of X-ray diffraction (XRD), FTIR spectrometer(FT-IR), Nitrogen adsorption analyzer and scanning electron microscope (SEM), thestructure of the catalyst was characterized. It turned out that the catalyst possessedmesoporous structure, large specific surface area（724.25m2g-1）and apertur（e4.71nm）.The catalytic performance of MCM-41supported palladium catalyst A and MCM-41supported copper (Ⅱ) catalyst using in Suzuki cross-coupling reaction betweenhalogenobenzene and NaBPh4had been investigated in the same reaction systemunder microwave irradiation condition and conventional heating condition. The workhad provided certain reference value for catalyzing Suzuki cross-coupling reaction withMCM-41supported palladium and copper catalyst. |
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