| 摘要 |
Abstract The present invention provides a para-dichlorobenzene separation and purification method to obtain high-purity, high-yield para-dichlorobenzene which has low energy consumption and 5 pollution-free.The method comprises dissolution, precipitation and fractional crystallization; In the dissolution and precipitation steps, raw para-dichlorobenzene is added in ethanol solution, then distilled water is added in with the temperature controlled in 5'C- 8'C, and a purity of 80% -8 8 % of para-dichlorobenzene is obtained after standing; Then, the crude para-dichlorobenzene is fractional crystallized to obtain para-dichlorobenzene with a purity no less than 99.9% and a 10 yield no less than 90%. In the separation and purification process, ethanol as the primary solvent and water as the precipitation solvent are low-cost, pollution-free solvents and the conditions are mild and are easy to operate;DCS system is used to achieve continuous production, to reduce sublimation and loss of raw material and to increase the processing capacity and product quality in the fractional crystallization process, and the economic benefits are significant. Mther Liquor f-'! TB ittp ICsn Fig. 1 |
