摘要
A highly selective synthesis of 2,6-dimethylnaphthanlene（2,6-DMN） by transalkylation between 2-methylnaphthanlene（2-MN） and 1,2,4,5-tetramethylbenzene（TeMB） was performed with 1-alkyl-3-methylimidazo- lium aluminum chloride（[Cnmim]Cl-AlCl3） ionic liquids（ILs） as catalysts. The influences of the alkyl group as the organic cation, the acidic strength of [C4mim]Cl-AlCl3 ILs as well as the reaction conditions on the catalytic performance were investigated. [C4mim]Cl-AlCl3 ILs[x（AlCl3）=71%] exhibited high activity and selectivity toward 2,6-DMN. The selectivity to 2,6-DMN and the 2,6-DMN/2,7-DMN ratio reached up to 68.2% and 3.7：1, respectively. The UV-Vis spectrum of TeMB treated by different ILs shows that the protonated degree of TeMB dependeds on the acidity strength of ILs, which has a significant impact on the reaction results. The high protonated degree of TeMB is advantageous to enhancing the conversion of transalkylation and the large stereo-hindrance effect of TeMB is favorable to improving the selecivity to 2,6-DMN.
A highly selective synthesis of 2,6-dimethylnaphthanlene（2,6-DMN） by transalkylation between 2-methylnaphthanlene（2-MN） and 1,2,4,5-tetramethylbenzene（TeMB） was performed with 1-alkyl-3-methylimidazo- lium aluminum chloride（[Cnmim]Cl-AlCl3） ionic liquids（ILs） as catalysts. The influences of the alkyl group as the organic cation, the acidic strength of [C4mim]Cl-AlCl3 ILs as well as the reaction conditions on the catalytic performance were investigated. [C4mim]Cl-AlCl3 ILs[x（AlCl3）=71%] exhibited high activity and selectivity toward 2,6-DMN. The selectivity to 2,6-DMN and the 2,6-DMN/2,7-DMN ratio reached up to 68.2% and 3.7：1, respectively. The UV-Vis spectrum of TeMB treated by different ILs shows that the protonated degree of TeMB dependeds on the acidity strength of ILs, which has a significant impact on the reaction results. The high protonated degree of TeMB is advantageous to enhancing the conversion of transalkylation and the large stereo-hindrance effect of TeMB is favorable to improving the selecivity to 2,6-DMN.
基金
Supported by the National Natural Science Foundation of China(No.21076065)
the Natural Science Foundation of Heilongjiang Province of China(No.ZD200820-02)
the Science&Technology Research Foundation of Education Bureau of Heilongjiang Province,China(No.11531266)
