Preparation Of Glycidyl Methacrylate Under Microwave Irradiation

Glycidyl methacrylate(GMA)is an important vinyl monomer with expoxy group.It is a high active monomer which is widely used in coating,painting,medicine and so on.The traditional method of preparing for GMA has many shortcomings,which severely limits its large-scale application.Such as,the process is cumbersome and complicated,and the synthesis conditions are harsh,the preparation time is longer.New requirements for the synthesis of GMA are proposed.In the thesis,glycidyl methacrylate is prepared by phase transfer method under microwave irradiation.Then,under the same microwave irradiation condition,the type of catalyst was changed.Glycidyl methacrylate was prepared by epoxy ring-opening and ring-closing reaction.Finally,in a continuous microwave reactor,glycidyl methacrylate was prepared.The specific content was as follows:(1)Using methacrylic acid(MAA)and epichlorohydrin(ECH)as raw materials and cetyltrimethylammonium bromide(CTMAB)as the catalyst,Glycidyl methacrylate was prepared by one-step method successfully.The infuluences of reaction parameters,such as raw material ratio,reaction temperature,reaction time,microwave power,and concentration of catalyst(CTMAB)on the preparation of GMA.GMA had been analyzed and characterized.The experimental result shows that:n(Sodium methacrylate):n(ECH)as 1:7,the catalyst dosage 20%,concentration of inhibitor 5%,reaction temperature at 90?.,the reaction time 20min,and the microwave power was 500W.Under these conditions the yield of product can be reached 80.61%.(2)Using ECH and MAA as raw materials,the type of catalyst was changed on the basis of the first step,Amines as the ring-opening catalyst,NaOH was a ring-closing catalyst,Glycidyl methacrylate(GMA)were prepared by two-step method successfully.The influences of parameters,such as raw material ratio,reaction temperature and reaction time on the preparation of GMA.The optimum reaction conditions for the preparation of glycidyl methacrylate(GMA)were determined.ring-opening reaction:reaction temp.45?,n(MAA):n(ECH)as 1:1.2,the catalyst dosage 1%,reaction time 15min,microwave power 500W,ring-closing reaction:n(MAA):n(ECH)as 1:1.0,reaction temp.35?,reaction time 15min,microwave power 300W.Under these conditions the yield of product can be reached 85.32%.This method is relatively simple compared to the former process,low energy consumption and environmental pollution.(3)Glycidyl methacrylate was prepared by two-step method with continuous microwave radiation.Using raw materials and the ring-opening catalyst were fully stirred and mixed,then flowed through the continuous microwave reactor at the constant flow rate and reach the collection bottle.The target product GMA was prepared by ring-closing catalyst.The optimal reaction conditions:n(MAA):n(ECH)=4:5,Hexamethylenetetramine catalyst 0.95%,microwave power 2.2KW,flow rate 10mL/min;the closed-loop conditions were the same as those of the second part,under these conditions the yield of GMA and purity were high.GMA were investigated by Infrared Spectrum and Nuclear Magnetic Resonance spectra.