A diffusion limited shrinking spherical particle model was used to describe the dissolution of relatively small cellulose particles with an initial radius of 1.15 mm, with a density of 0.75 g cm 3 in a 1 M sodium hydroxide (NaOH) solution.

The reaction takes place at 65C and 2 atm, with a 1st order surface reaction rate constant of 17.5 cms and with a diffusion coefficient of 2.1x10-10 m^2/s^1. Assuming that 2 mol of cellulose is needed, and that the resistance from the reaction control is negligible. Calculate the time in minutes needed for complete dissolution of the cellulose particles.

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