The Preparation Of Glyphosate From Nphosphonomethyl Iminodiacetic Acid VIA Visible-light Catalytic Oxidation

Glyphosate is a high efficient, low toxic and broad spectrum herbicide.The main methods for its synthesis are glycine method or IDA method.For the IDA route, the catalytic oxidation of N-phosphonomethyl iminodiacetic acid to give glyphosate has the advantage of mild reaction conditions, good activity and selectivity of catalyst, high purity of product.Visible light is natural abundance, green, and pollution-free. The synthesis of glyphosate by using visible light catalytic oxidation process is an innovative and meaningful research. In this paper, we mainly investigate the visible light catalytic activity of titanium dioxide（TiO2）,graphite like carbon nitride materials（g-C₃N₄）, TiO₂/g-C)3N₄, mesoporous graphite carbon nitride materials（mpg-C3N4: mpg CND, mpgCNM,mpgCNU, mpgCNT） with dicyandiamide, melamine, urea and thiourea as precursors, respectively. Then the effect of catalyst preparation temperature on the visible light catalytic reaction activity（such as mpgCNT400, mpgCNT450, mpg CNT500, mpg CNT550, mpgCNT600）was also investigated.After screening of visible light catalyst, reaction conditions and the modification of visible light catalyst, it was found that the best catalytic activity of mesoporous carbon nitride was prepared by using thiourea asthe precursor at 550℃, and the yield of glyphosate was 80%, and the selectivity was 84%.