Production of oxalic acid from sawdust using coal fly ash as a catalyst

Abstract The production of oxalic acid from sawdust using a mixture of strong nitric acid and concentrated sulphuric acid with coal fly ash as a catalyst has been explored. Operating parameters affecting the reaction were determined to be temperature, mesh size and amount of fly ash catalyst, time and the $${\text{HNO}}_{3} :{\text{H}}_{2} {\text{SO}}_{4}$$ HNO3:H2SO4 ratio. A maximum oxalic acid yield of 84% was obtained using a mixture of 60% $${\text{HNO}}_{3} {\text{ and }}40 \%{\text{ H}}_{2} {\text{SO}}_{4}$$ HNO3and40%H2SO4 at 70 °C and a reaction time of 150 minutes. Coal fly ash with particle size of 50–100 μm proved to be a suitable and efficient catalyst, and the optimum quantity of catalyst employed was 5g of fly ash for every 100g of sawdust.