| 摘要 |
Purification of organic substances crystallised from solns. or molten masses and which have been separated by filtration, is effected by passing through the filter cake, a stream of an inert gas at a temp. close to the solidification pt. of the pure intermediate product. The filtration and treatment with inert gas may be effected continuously with a rotary filter, the inert gas circulating advantageously, in a closed circuit. Process is applicable to aromatic intermediate products, e.g. derivs. of benzene, toluene and xylene, higher homologues of crystallisable isomer mixtures which do not tend to form mixed crystals, pure cpds. such as polychlorobenzene, nitrochlorobenzene nitrotoluene, chloronitrotoluene and nitroxylene are obtained. |
