In search of a recyclable sulphur dioxide sponge-a new look at an old system.

The sulphur dioxide content and thermal stability of the quinol-SO2 clathrate have been studied by thermogravimetric analysis (TG), its derivative (DTG) and differential scanning calorimetry (DSC). These analyses demonstrated the thermal recoverability of the quinol from the clathrate and hence its potential use as a sponge for SO2 present in the environment as a pollutant. Similarly, Bu4N(+)I(-) was found to occlude NO2 and SO2 at 50°C in solution.