Synthesis of Phenoxy Acetic Acid by Catalytic Oxidation of Phenoxyethanol with Oxygen

Phenoxy acetic acid was prepared by catalytic oxidation reaction,using phenoxyethanol and oxygen as raw materials.HPLC(liquid chromatograph) was used for quantitative analysis,and FTIR(infrared absorption spectrum),NMR(nuclear magnetic resonance) and GC-MS(gas chromatography mass spectrometry) were used for qualitative analysis.The effects of catalysts,solvents,and reaction conditions on reaction results were investigated.The results show that N-hydroxy phthalimide(NHPI) is an efficient catalyst,and dimethylglyoxime and cobaltous acetate are suitable cocatalysts,and acetonitrile is a suitable solvent.The yield of phenoxy acetic acid could reach 68.6% when phenoxyethanol was 0.1 mol,the amount of NHPI was 8% of molar weight of phenoxyethanol,the suitable molar ratio of NHPI∶dimethylglyoxime∶cobaltous acetate=8∶7.5∶1 and the reaction took place at 80 ℃,0.8 MPa O2 for 6 h.The plausible reaction pathway was proposed based on GC-MS analysis.