Catalyzed By Ionic Liquid Toluene Selective Nitration

Ionic liquids as new solvents and new catalytic materials have been paid attention all over the word.Development of new procedures in organic synthesis using task-specific ionic liquids as solvents and catalysts has become a novel research area in recent years.As the same time,the recent progress of region selectivity research for aromatic nitration is one of the hottest topics.The effects of functionalized ionic liquids on the region selectivity and conversion of nitration reaction for toluene as substrates are investigated in this paper.Twenty-two ionic liquids had been synthesized by using methylimidazole,pyridine,triethylamine as basic source in this paper.Five SO₃H-functionalized ionic liquids such as[MIMPS]HSO₄, [p-SABMIM]HSO₄,[PSPy]HSO₄,[p-SABPy]HSO₄ and[TEPSA]HSO₄ were chosen by investigating the catalytic capacity in the nitration reaction for toluene.Considering the toluene as nitration substrate,using the five SO₃H-functionalized ionic liquids respectively as catalyst,the technology research analysis the reaction conditions including reaction temperature,strength of the nitro-sulfuric,dosage of ionic liquids and so on.Experiments showed that all of the five SO₃H-functionalized ionic liquids could catalyze the nitration of toluene well.Among the five SO₃H-functionalized ionic liquids,ionic liquid [p-SABPy]HSO₄ has the best catalytic capacity.The conversion of toluene was up to 97.4%,the content of m-nirotoluene was 5.1%and o/p valued of 1.28,when the reaction was carried out at 40℃for 3 hours,and the molar ratio of toluene to ionic liquid was 10:3. The five SO₃H-functionalized ionic liquids were recycled four times,and no change in activity.The experimental data is useful to its industrialization,and it has important leading meaning.