Study On The Polyethylene Dlycol Catalytic Phenolic Hydroxyl Methylation Under The Microwave-assisted

Objective To the o-substituted methyl phenate and p-substituted methy phenyl as raw material, DMC as methylating reagent, different molecular weight polyethylene glycol(PEG) as the catalyst, under the condition of microwave assisted synthesis of the corresponding phenylethers. Investigation catalytic activity of phase transfer catalyst, to explore the influencing factors of the methylation reaction, to determine the optimum conditions of synthesis.Methods By using the method of microwave radiation, the selection of different molecular weight polyethylene glycol as the catalyst, under the condition of microwave assisted synthesis of the corresponding phenylethers. Effect of the ratio of starting materials,temperature and catalyst dosage, as well as time and catalysts on yield were investigated. according to the process route was optimized by single factor test. Products were confirmed by 1HNMR, 13 CNMR were used to confirm the structure.Results The results showed that under the optimized reaction conditions of the PEG-400 as catalysts,n(o-substituted phenol): n(K2CO3): n(PEG-400): n(DMC)=1:0.65:0.4:9,reacation temperature is 90 ℃, the yield of o-nitroanisole reached 78.43%; the yield of o-bromoansisole reached 69.56%; the yield of reached 2-Chloroanisole 71.80%; the yield of guaiacol reached 76.83%; the yield of reached p-acetaniside 84.67%.By choosing PEG-400 as the catalyst to get p-substituted methyl phenate,the better process condition can be conducted as follows: n(p-substituted phenol): n(K2CO3): n(PEG-400): n(DMC)=1:0.6:0.3:8,reacation temperature is 90 ℃, the yield of p-nitroanisole reached 80.59%; the yield of p-bromoansisole reached 74.2%; the yield of reached 4-Chloroanisole76.36%; the yield of reached p-methoxyohenol reached 76.83%; the yield of reached p-acetaniside 85.34%.Conclusions Underthe condition of microwave successfully assisted of corresponding phenylethers, DMC as methylating reagent, PEG as the catalyst, the methold has the advantages of no pollution,high safely, simple operation and energy consumption, ect. it can be applied to the study of green chemistry.