Searching the evidence for the intercalation of bromine in high-rank coal

Similar to graphite, meta-anthracite absorbs bromine at room temperature to a concentration close to that of stage-2 graphite-bromine. Subsequent desorption at room temperature was incomplete, indicating that 88% of the bromine was loosely held and 12% was relatively strongly held in the meta-anthracite. The rate of bromine absorption and the amount and rate of bromine desorption were greater for meta-anthracite than for graphite. X-Ray diffraction, electron diffraction and differential scanning calorimetry showed the absence of intralayer or interlayer intercalate ordering in brominated meta-anthracite after desorption, hence yielding no evidence for intercalation. We conclude that the meta-anthracite was not intercalated. The ignition temperature of meta-anthracite was lowered by ≈ 80 °C by the bromination.