神马作文网傅-克反应卤代烃酰卤活性问题!
来源：学生作业帮 编辑：神马作文网作业帮 分类：英语作业 时间：2024/11/13 21:11:06
傅-克反应卤代烃酰卤活性问题!
邢大本说：傅-克反应烷基化卤代烃活性F>Cl>Br>I,酰基化酰卤活性I>Br>Cl>F,活性为什么是相反的?
大虾们分不是问题
是因为机理不同吗 但是烷基化也可以由c正离子历程啊
邢大本说：傅-克反应烷基化卤代烃活性F>Cl>Br>I,酰基化酰卤活性I>Br>Cl>F,活性为什么是相反的?
大虾们分不是问题
是因为机理不同吗 但是烷基化也可以由c正离子历程啊
March上面有介绍酰基化酰卤活性I>Br>Cl>F并不是绝对的,原因可能是在形成Wheland中间体后,进一步形成产物时,I的离去能力更强,C-I键能也最小,所以I活性更高,至于烷基化,可能是由于F的体积较小,配合M的能力较强,导致更易形成R+,所以F活性更高
LZ可参考以下文献
1、Challoway.N.O,JACS,59,1474(1937)
2、Brown and Jungk,JACS,77,5584(1955)
3、Yamase,Bull,Chem,Soc,Jpn,34,480（1961）
4、Corrio,Bull,Soc,Chim,Fr,821（1965）
文献1中的描述
We have found that for the acyl halides the order of activity for the halogens is as might be expected, I > Br > C1> F. The extreme sensitiveness of acetyl iodide to aluminum chloride caused a marked decomposition but did not materially interfere with the determination. For the alkyl halides the surprising order found was F>CI>Br>I. In fact, the iodine was so inert that n-butyl iodide did not react with benzene in eighteen hours in the presence of aluminum chloride at 29°C, though the other halides reacted at rapid rates at lower temperatures. It is also of interest to note that the n-butyl iodide was stable in the reaction and was recovered unchanged.
LZ可参考以下文献
1、Challoway.N.O,JACS,59,1474(1937)
2、Brown and Jungk,JACS,77,5584(1955)
3、Yamase,Bull,Chem,Soc,Jpn,34,480（1961）
4、Corrio,Bull,Soc,Chim,Fr,821（1965）
文献1中的描述
We have found that for the acyl halides the order of activity for the halogens is as might be expected, I > Br > C1> F. The extreme sensitiveness of acetyl iodide to aluminum chloride caused a marked decomposition but did not materially interfere with the determination. For the alkyl halides the surprising order found was F>CI>Br>I. In fact, the iodine was so inert that n-butyl iodide did not react with benzene in eighteen hours in the presence of aluminum chloride at 29°C, though the other halides reacted at rapid rates at lower temperatures. It is also of interest to note that the n-butyl iodide was stable in the reaction and was recovered unchanged.