| 摘要 |
1,106,988. Solvent recovery; purification of polyolefines. REXALL DRUG & CHEMICAL CO. 28 March, 1966 [15 April, 1965], No. 13621/66. Heading B1B. Solvent, e.g. an alkanol or a glycol, is recovered from a solution thereof obtained from solvent extraction of metallic catalyst residues from a polyolefine, by mixing the solution with a hot polyalkylbenzene oil having a high boiling point, e.g. in the range 375‹ to 400‹F, so as to volatilize the solvent. The polyalkyl benzene oil preferably has a viscosity of from 10 to 100 ops at room temperature. In an example, the product of the polymerization of propylene in the presence of an aluminium alkyl and titanium trichloride is treated with a mixture of isopropanol and n-heptane. The feed solution containing the solvent is preferably concentrated in evaporators 2 and 4 to raise the solids content to 20 to 60% by weight before contacting it with the oil. The concentrated solution withdrawn from evaporation 4 is mixed in line 15 with polyethylbenzene oil at atemperature of 400‹ to 600‹F, the mixture passing to flash separator 6 where the remaining solvent is flashed off, the vapours from the evaporators being condensed in coolers 31 and 32 and collected in tank 30 for subsequent recycling. Part of the oil and residual solution withdrawn from the base of the separator 6 is recycled to the separator, the remainder being burned in incinerator 8. The oil for mixing with the solution is pre-heated by indirect, heat exchange in incinerator 8.
|
