Low-temperature oxidation of guaiacol to maleic acid over TS-1 catalyst in alkaline aqueous H2O2 solutions

To mitigate the negative environmental impact of greenhouse gas (GHG) emission originated from the use of fossil fuels, the chemical world is switching to utilize renewable biomass resources. Co-producing value-added chemicals is important for an integrated biorefinery to improve economics of biofuels. Lignin derived compounds, e.g. guaiacol, are common by-products of fast pyrolysis of lignocellulosic biomass. In this paper, the feasibility of low-temperature selective oxidation of guaiacol to value-added dicarboxylic acids, e.g. maleic acid, was investigated using titanium silicalite/hydrogen peroxide (TS-1/H2O2) reaction system. Under the reaction conditions (80 °C and the initial pH = 13.3), the molar yields of maleic acid from guaiacol were approximately 20%–30%. The effects of catalyst amount, initial pH values, reaction time, and temperature on the yields of maleic acid were investigated. A possible reaction mechanism of TS-1 catalyzed aromatic ring opening was proposed.

Graphical AbstractA novel oxidative ring opening method was developed for the conversion of guaiacol to maleic acid with a TS-1 catalyst in alkaline aqueous H2O2 solutions.Figure optionsDownload full-size imageDownload as PowerPoint slide