| 摘要 |
1275232 Sublimation separation of organic compounds from solutions DIAMOND SHAMROCK CORP 15 April 1970 [16 April 1969] 18025/70 Heading BIB [Also in Division C2] A sublimable organic compound, such as hydroquinone, naphthalene, p-dichlorobenzene or nicotinic acid, is separated from a slurry of finely-divided inert solids in a solution of the organic compound in a solvent having a boiling point lower than the melting point of the organic compound by heating the slurry, or filtered solution, under subatmospheric pressure to vaporize the solvent at a temperature below the melting point of the organic compound, then heating the dry solid residue to a higher temperature at a lower pressure to sublime the organic compound, and condensing the vapours of the organic compound in the form of a crystalline deposit. One manner of carrying out the process is to boil off some of the solvent from the slurry in a heated agitated tank, and then distribute the concentrate on the hollow trays 10" of drier-sublimer unit, wherein it is heated under vacuum so that the remaining solvent is first removed, and then the organic compound is sublimed, the sublimed vapours being condensed on a hollow plate 25 from which the crystalline sublimate is transferred by a rotary scraper 28 into cooler 30. Heating fluid (e.g. oil) is pumped through jacket 12, trays 10" and jackets 15, 16, 17. Another heat-transfer medium is pumped through hollow plate 25. The evaporation vessel 10 is covered with thermal-insulation material 10'; and the vapours pass from vessel 10 to vessel 20 through thermally-insulated conduit 22. Solvent-vapour is removed from vessel 10 to an aspirator through valved-coupling 39; but when sublimation is to be effected, coupling 39 is closed, and a two-stage vacuum pump, connected to vessel 20 at 32, is actuated. Plate 25 may be replaced by a rotary drum condenser.
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