Search

The preparation of active carbons containing nitrogen surface functions is considered by ammoxidation of various raw materials like pinewood, peat and lignite. To have an accurate knowledge of the nitrogen functions introduced, diffuse reflectance IR/FT and X-ray photoelectron spectroscopies were used. Taking into account the complexity of the raw materials, the structural characterisation of the cellulose ammoxidation products was undertaken in the first step of our study, since cellulose is one of the major compounds of woods. The thermal treatment of cellulose, at around 250 °C and at different durations (1, 2, 4 h), was realised for comparison under several conditions: air, argon, ammonia and air–ammonia mixtures (ammoxidation). Several nitrogenated structures were characterised. The mechanism of their formation from the C4 fragment formed from the heterolytic cleavage of cellulose by thermal treatment was proposed pointing out the fundamental role of intermediate imine function. [Copyright &y& Elsevier]