Study On The Catalyze Oxidation Of Nitrotoluene In Liquid-Phase

Nitrobenzoic acid is a kind of very important fine chemical product,which are used extensively. Our use Co(acac)2 as a catalyst in this work, exploring new way to produce nitrobenzoic acid from nitrotoluene under the prue oxygen in basic medium.As we all known, it is very difficult to convert the ring-substituted methylbenzenes to the corresponding carboxylic acids, So high selectivity and under the medium reaction conditions to produce nitrobenzoic acid is our goal with great value in reality and in theory respectively. How can we solve this problem? First, we must find a way to let the oxygen activated; secondly, let the H atom cleavage from the methyl, and turn to carbanions; finally, the activated dioxygen react with carbanions, so the problem of oxidizate nitrotoluene is sloved in the end.During the time of experiment, some interesting phenomenon are attract our attention: under this reaction system, MNT,PNT.ONT have the different reactivity.The reaction activity of nitrotoluene decrease in the following order: PNT>ONT >MNT. The reasons of this phenomenon are due to the figure of substrates and its electronic structure. The reaction rate is determined by the activity of C-H bond in side-chain alkyl.In the discussion, our find temperature effect the reaction deeply. It is reported that added temperature can promote the H atom cleavage from the side-chain alkyl. In the study of different catalyst on the reaction, our find complex with the same center metal ion have the same catalyze function in those kinds of reaction, maybe the change of ligand cause no affect on reaction. In this system, the existence of NaOH is important to this kinds of reaction, and studies have demonstate that the strong base(KOH, NaOH et al.) can induce the reaction of cleavage H atom from methyl on the ring of deactivated toluenes,such as nitrotoluene. The carbanions caused by base are the very important reaction intermediums, which determined the reaction rate and reaction effect. Less water cause no effect on the conversion and selectivity, which proved the reaction is not a typical free radical reaction.This reaction system is very simple and easy operation. Catalyze oxidation 4-methoxy-2-methyl-l-nitrobenzene with high yield under this reaction system has proved its application.