Abstract
In order to obtain highly purified organic substances, sweating of crude crystalline particles was investigated with two organics; m-chloronitrobenzene and p-dichlorobenzene. By maintaining the crude crystals at a temperature close to the equilibrium one in order to form melts and followed by rapid drainage of the melts, the crystals were found to be purified upto 99.99% within 1.5 or 2hr. The final purity was found to depend on the sweating temperature. The rate of purification was analyzed with a model that the drainage of the melts dominated the phenomena of sweating. Empirically, the rate of removal of the melts was expressed as k(α-α∞)2 where k is the coefficient for purification rates and (α-α∞) denotes the free melts removable by the sweating. The values of k were found to be common to the examined two organics and α∞, was a function of the sweating temperature. The purification rate was thus analyzed quantitatively.
