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本文主要研究P—联三苯直接溴化产物的分离与提纯。将直接溴化产物用石油醚(沸程为60～90℃)萃取,得到P—联三苯和4—溴—P—联三苯混合物。该混合物采用络合色谱薄层分离方法,即用国产硅胶GF_(254)制成的GF_(254)—AgNo_3版,以石油醚(沸程为60～90℃)为展开剂,在国产LBC—1型旋转薄层分析仪上进行分离,得到较好的效果。从分离结果对产物进行了定量分析。并根据络合薄层色谱中测得的R_f值推断溴在4—溴—P—联三苯的取代效应是吸电子的。从分析结果探讨了4—溴—P—联三苯中溴原子对P—联三苯环中4″位活性的影响。初步结论是:在室温下,溴在P—联三苯中,诱导效应大于共轭效应,具有致钝作用,类似于溴在溴苯中对苯环活性的影响。
This article mainly studies the separation and purification of P- The direct brominated product was extracted with petroleum ether (boiling range 60-90 ° C) to give a mixture of P- biphenyl and 4-bromo-P-terphenyl. The mixture was separated by a complex chromatographic method, that is, GF_ (254) -AgNo_3 plate made with domestic silica gel GF 254 and petroleum ether (boiling range 60-90 ° C) 1-type rotating thin-layer analyzer for separation, get better results. The product was quantitatively analyzed from the results of the separation. According to the measured Rf value in the complex thin-layer chromatography, the substitution effect of bromine in 4-bromo-P-terphenyl was electron-withdrawing. The effects of bromine atoms in 4-bromo-P-terphenyl on the 4 "position of p-tricyclic benzene ring were discussed from the results of the analysis.It is concluded that bromine is induced in P- biphenyl at room temperature The effect is greater than the conjugate effect, has a blunt effect, similar to bromine in bromobenzene benzene ring activity.