Catalytic decarboxylation of Elbistan lignite

Official URL: http://dx.doi.org/10.1080/00908310290086581

Decarboxylation of low-rank Turk-ish Elbistan lignite at low temperatures by utilizing cupric sulphate as a catalyst was investigated. The gross calorific value of the lignite treated with 4 wt% Cu2+ and decarboxylated at 200degreesC for 30 min increased about 40%. Fourier transform infrared (FTIR) and solid-state C-13 nuclear magnetic resonance (NMR) methods have been used to investigate the changes in the oxygen functional groups in Elbistan lignite that occurred during decarboxylation. Activation energies of the decarboxylation reactions were calculated as 100.7 kJ/mol and 44.5 kJ/mol for original and treated Elbistan lignite samples, respectively. The sequence in the rate of loss of the oxygen functional groups was as carboxyl, carbonyl, hydroxyl, and carboxylate ions. With the presence of Cu2+ ions, decarboxylation reactions procedeed with higher rates by a dissociative mechanism to release CO or CO2 simply by heating.