| Solvent method is one of the effective methods for the separation and purification of anthracene and carbazole form crude anthracene or anthracene oil. The select of solvent system often play a key role in the separation and purification process of anthracene and carbazole, especially, the separation process of anthracene and carbazole. Therefore, in this thesis, the author has discussed the effect of interaction between solute and solvent on the solubility and selectivity of anthracene and carbazole in solvent, by determining the solubility of anthracene/carbazole in DMF/IPA, calculating the intermolecular Van der waal’s attractive energy, and detecting the intermolecular hydrogen bond. And the discussion would provide the theory basis for the select of solvent in the industrial process.In this thesis, the author has studied the solubility of anthracene and carbazole in DMF, IPA and DMF-IPA mixed solvent. In those solvent systems studied, the solubility of anthracene and carbazole was in the order of DMF>DMF-IPA>IPA. In the DMF-IPA mixed solvent, the inhibition effect on the solubility of anthracene/carbazole increased gradually with the increase of amount of IPA adding into DMF-IPA mixed solvent. The solubility selectivity of those solvents to carbazole and anthracene was in the order of IPA>DMF-IPA>DMF, and the value quickly decreased with the temperature increase. In the mixed solvent, the solubility selectivity increased with the amount increase of IPA in DMF-IPA mixed solvent.On the other hand, in the thesis, based on the Matlab software, the intermolecular Van der Waal’s attractive energy was calculated, between anthracene, carbazole, DMF and IPA molecule. And the intermolecular hydrogen bond was detected with 1H NMR. At room temperature, in the anthracene/carbazole and DMF molecule system, the attractive energy between anthracene and anthracene as well as between DMF and DMF are larger than that between anthracene and DMF, in addition, the intermolecular hydrogen bond hasn’t been detected between anthracene and DMF molecule. Therefore, the intermolecular Van der Waal’s attractive energy is one key factor to influence the solubility of anthracene in DMF. Compared with anthracene, the attractive energy between carbazole and carbazole is equivalent to that between carbazole and DMF, together with the existence of the hydrogen bond between carbazole and DMF molecule, therefore, carbazole can easily dissolve in DMF. In the anthracene/carbazole and IPA system, though the attractive energy between IPA and IPA is approximate to that between anthracene/carbazole and IPA, owing to the existence of IPA intermolecular hydrogen bond, the interaction energy between IPA and IPA was greatly enhanced, therefore, compared with DMF, the solubility of anthracene in IPA is very small. Correspondingly, though the existence of hydrogen bond between carbazole and IPA, for the hydrogen bond between IPA molecules, the solubility of carbazole in IPA is also very small. In DMF-IPA mixed solvent, for the intermolecular hydrogen bond between DMF and IPA, the effective interaction sites of DMF with anthracene/carbazole were greatly reduced. Therefore, in the mixed solvent, the solubility of anthracene was tremendously restrained. For the formation of complex hydrogen bond network between carbazole, DMF and IPA, the solubility of carbazole in the mixed solvent was also restrained.Based on the solubility data and the AN-CAR-SOLVENT liquid-solid ternary phase diagram, the DMF-IPA mixed solvent was used to separate anthracene and carbazole, and the volume ratio adopted was 0.8:0.2 in the mixed solvent. The AN-CAR binary mixture was dissolved at 100℃ in the mixed solvent with a 2.5:1.0 liquid-solid ratio, and filtered at 30℃. After that, the anthracene content can be decreased to 6.0 to 8.0%(mass fraction). After three times extraction by xylene and chlorobenzene, the carbazole purity can reach above 97% and 98% respectively, and the single-pass yield of carbazole can also reach above 41.0 and 43.0% respectively. |
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