The Kinetics of Nitration of Aromatic Nitro Compounds in Sulfuric Acid1
The Kinetics of Nitration of Aromatic Nitro Compounds in Sulfuric Acid1
复制标题
芳香硝基化合物在硫酸中的硝化动力学1
DOI：
10.1021/ja01214a001
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发表时间：
1946
影响因子：
15
通讯作者：
M. Kharasch
中科院分区：
文献类型：
--
作者：
F. Westheimer;M. Kharasch
研究了芳香族硝基化合物在硫酸溶液中的硝化反应动力学，以期阐明反应机理。与Martinsen的开创性工作相一致，2发现芳香族硝基化合物与硝酸的二级反应在90%左右的硫酸中有最大速率。对最大速率条件的更精确的研究表明，它发生在一定的酸度(由Hammett的HO函数定义)，而不是在一定浓度的硫酸。这一发现又强烈地表明，硝酸的电离参与了最大值的确定。最可能的电离是HX03+H2SO4->；-H2N03++HSO4-(I)HX03+2HoS04->；-H30++X02++2HS04-(2)与方程式1和方程式2所示的电离类型平行的指示剂的电离。结果表明，公式2中所示类型的电离(而不是公式1中所示的类型)将解释速率的千倍增长
I. Introduction The kinetics of the nitration of aromatic nitro compounds in sulfuric acid solution has been studied with a view toward elucidating the mech-anism of the reaction. In conformity with the pioneer work of Martinsen, 2 it was found that the second orderreaction between aromatic nitro compounds and nitric acid has a maximum rate in about 90% sulfuric acid. More precise in-vestigation of the conditions for maximum rate showed that it occurred at a definite acidity (de-fined by Hammett’s Ho function) rather than at a definite concentration of sulfuric acid. This dis-covery in turn strongly suggested that an ionization of the nitric acid was involved in the deter-mination of the maximum. The most probable ionizations areHX03+ H2SO4—>- H2N03++ HSO4-(I) HX03+ 2HoS04—>- H30++ X02++ 2HS04-(2) Ionizations of indicators which parallel both the type of ionization shown in equation 1 and that shown in equation 2 were investigated. It was show'll that an ionization of the type shown in equation 2 (and not that shown in equation 1) will account for the thousand-fold increase in rate