Abstract
Purification of 2,6-dimethylnaphthalene(2,6-DMNA) from the distillate containing a mixture of dimethylnaphthalene(DMNA) isomers of very high concentration was investigated by crystallization-recrystallization combination as a after-treatment for separation and purification of 2,6-DMNA in the light cycle oil(LCO). The separation of individual isomers of DMNA was studied by crystallization with the distillate as a feed. 2,6-DMNA, 2,7-dimethylnaphthalene(2,7-DMNA) and 2,3-dimethylnaphthalene(2,3-DMNA) were concentrated to crystal, and it was fould that separation between a group of 2,6-, 2,7-, 2,3-DMNA isomers and a group of the other DMNA isomers was possible. However, it was not possible to separate 2,6-, 2,7- and 2,3-DMNA from one another. To select the most suitable recrystallization solvent for purification of 2,6-DMNA, several conventional solvents, which have been employed commercially as recrystallization solvents for high purity performance, were tested, through measurement of solubility of 2,6- and 2,7-DMNA. The solvent used were hexane, iso-propyl ether, ethyl acetate and ethanol. From the solubility results for 2,6- and 2,7-DMNA, ethanol seemed to be the most suitable solvent for purification of 2,6-DMNA. Finally, with crystal recovered by crystallization as a feed and ethanol as a solvent, recrystallization experiments were conducted under various conditions. Purification of 2,6-DMNA was easily done with increasing operating temperature and solvent to feed ratio. These results show that the crystallization-recrystallization combination is an effective one for separation of individual isomers of DMNA.
접촉분해경유(LCO)중에 함유된 2,6-dimethylnaphthalene(2,6-DMNA)의 분리, 정제를 위한 후처리조작으로서 고농도의 dimethylnaphthalene(DMNA) 이성체 혼합물을 함유한 유출액으로부터 2,6-DMNA의 정제를 정석-재결정의 조합에 의해 검토했다. 유출액의 정석에 의해 회수된 결정중에는 2,6-DMNA, 2,7-dimethylnaphthalene(2,7-DMNA)과 2,3-dimethylnaphthalene(2,3-DMNA)이 농축되어, 이들 3 이성체와 그 외의 DMNA 이성체간 분리는 가능하였으나, 2,6-, 2,7-과 2,3-DMNA 이성체간의 분리는 곤란했다. 2,6-DMNA의 정제에 적합한 용매의 선정을 위해, 재결정 용매로 Hexane, iso-propyl ether, ethyl acetate와 ethanol을 사용하여 2,6-과 2,7-DMNA의 용해도를 측정한 결과, 2,6-DMNA의 정제에는 ethanol이 가장 적합한 용매이었다. 또, 원료로 정석에서 회수된 결정을, 용매로 ethanol을 사용하여 재결정을 행해 2,6-DMNA의 정제에 대한 조작인자의 영향을 검토한 결과, 재결정 온도의 상승 및 용매/원료 질량비가 증가함에 따라서 2,6-DMNA의 정제는 용이했다. 본 연구에서 채용한 정석-재결정법은 DMNA 이성체 성분간 분리에 대한 유효한 분리조합의 하나임이 입증되었다.