二苯甲烷制备实验改进研究与拓展OA

Carbonyl reduction reactions constitute a fundamental component in organic chemistry education.In current undergraduate laboratory instruction,this transformation is predominantly demonstrated through the Huang-Minlon reduction method,a pivotal method developed in China.However,this conventional experiment presents several pedagogical challenges,including the use of highly toxic hydrazine hydrate,excessive high-temperature byproduct formation,cumbersome workup procedures,and notable safety concerns.To address these limitations,we have implemented the following modifications to the diphenylmethane synthesis experiment:1)replacement of the N2H4ꞏH2O-KOH system with an environmentally benign Polymethylhydrosiloxane(PMHS)-FeCl3 reduction system;2)substitution of hazardous diethylene glycol solvent(which releases toxic and irritating fumes at elevated temperatures)with stable and easily handled 1,2-dichloroethane;3)reduction of reaction temperature from 140-195 to 70 ℃;4)shortening of reaction duration from 4 to 1 h;and 5)adoption of a simplified workup procedure involving grinding and vacuum filtration instead of complex and potentially hazardous reduced-pressure distillation.Furthermore,by incorporating analytical techniques such as thin-layer chromatography,column chromatography purification,and spectroscopic characterization(Infrared Spectroscopy(IR)and Nuclear Magnetic Resonance(NMR)),we have developed this into an 8-hour comprehensive experiment.The extended protocol includes selective deoxygenative reduction of the pharmaceutical compound ketoprofen,thereby enhancing students'comprehensive chemical competencies.