Synthesis, identification and evaluation of furfural from rice straw

Synthesis of furfural from rice straw was carried out under mild conditions in an attempt to create value-added products from rice straw, which has become a seasonal source of air pollution in granary areas of Malaysia due to open burning. It was based on the conversion of the pentosan fraction in rice straw into pentose, which was then cyclodehydrated to furfural using dilute sulphuric acid. Furfural obtained was characterised using infrared analysis (IR), gas chromatography (GC) and gas chromatography with mass spectrophotometer (GCMS). IR spectrum exhibited a very strong absorption indicating the presence of the conjugated carbonyl (C=0) group. Results obtained from GC and GCMS also identified the presence of furfural with a probability of 98.4%. A molecular ion peak at m/z 96.03 was obtained, which correlates to a molecular formula of furfural, namely C 5H 4O2 . The product was colourless but turned yellowish and then dark brown upon exposure to air and light. It had a smell resembling that of bitter almond and its vapour was irritable to skin and eyes. The yield of furfural synthesised is affected by the concentration of acid and the catalyst.