The invention encompasses processes for obtaining pure armodafinil substantially free of disulfide impurities that is suitable for use on an industrial scale. In particular, a processes for purifying armodafinil from bis(diphenylmethyl)disulfide comprising: dissolving crude armodafinil in ethanol to form a solution; adding a solvent selected from the group consisting of linear or branched C5-C8 alkyl, linear or branched C5-C8 ether, and mixtures thereof to the solution to form a reaction mixture; cooling the reaction mixture; and isolating pure armodafinil from the reaction mixture.