  In this study, lignin was oxidised to vanillin by means of oxygen in ionic
liquid (1,3-dimethylimidazolium methylsulphate) medium. The parameters of the
oxidation reaction that have been investigated were the following:
concentration of oxygen (5, 10, 15 and 20 ft3 h-1), reaction time (2, 4, 6, 8
and 10 h) and reaction temperature (25, 40, 60, 80 and 100{\deg}C). The Fourier
transform infrared spectroscopy, high performance liquid chromatography and
ultraviolet-visible analyses were used to characterise the product. The results
revealed vanillin as the product obtained via the oxidation reaction. The
optimum parameters of vanillin production were 20 ft3 h-1 of oxygen for 10 h at
100{\deg}C. In conclusion, 1,3-dimethylimidazolium methylsulphate could be used
as an oxidation reaction medium for the production of vanillin from rubber wood
lignin.
