Application Of Ionic Liquid-supported Catalysts In The Oxidation Of Trimethylphenol

2,3,5-Trimethyl-1,4-benzoquione(TMBQ) is a key intermediate for the synthesis of vitamin E, which can be obtained from the oxidation of 2,3,6-trimethylphenol (TMP). However, the traditional methods are in need of large amount of catalysts and could not be recycled. A series of novel acetylacetone metal catalysts, which are supported on ionic liquids were applied in the reaction to replace traditional methods. On the one hand, the catalysts have some characters of ionic liquids (ILs), which can be recycled easily in organic solvent. One the other hand, the novel catalysts showed improvements on activity and selectivity compared with the other organometallic catalysts, especially compared with traditional acetylacetone metal catalyst in this reaction. All these researches are of great practical significance for the clean production of Vitamin E.In this dissertation, the oxidation reaction of TMP to TMBQ was researched, and the novel IL-supported acetylacetone metal catalysts were involved in the catalysis reaction. After that, ILs were used as the co-catalysts in the reaction.As the co-catalysts, ILs were involved in the oxidation reaction of TMP catalysed by the novel IL-supported acetylacetone metal catalysts for the first time. They enriched the catalytic system greatly in term of their tunable properties. This pronounced regularity between microstructure and macroscopic properties of ionic liquids may enlighten us to devise novel and efficient types of task-specific cocatalysts to improve the oxidation reaction.In this dissertation, influences of IL-supported acetylacetone metal catalysts in different situations on the TMP oxidation reaction were explored. The result shows that the catalytical activity order of the three catalysts is [acae-trimami][Cl]-Cu > [acae-mim][Cl]-Cu > [acae-py][Cl]-Cu. However, the selectivity of TMBQ is on the contrary. We found that it shows the highest selectivity of TMBQ and appropriate reaction time and activity at 70℃. The catalytical activity order of the five IL-supported acetylacetone metal catalysts with different metals on them is: [acae-mim][Cl]-Cu > [acae-mim][Cl]-Co > [acae-mim][Cl]-Cr > [acae-mim][Cl]-Ni > [acae-mim][CI]-Mn. The catalysts show higher catalytical activity and selectivity of TMBQ when concentration of catalysts is 10mol% of TMP at 70℃. In this situation, [acae-py][Cl]-Cu catalyst can obtain a 59.0% selectivity. ILs can be recycled for four times and still have a 68.0% selectivity of TMBQ.Later on, influences of ILs co-catalysts to the oxidation reaction of TMP while IL-supported acetylacetone metal as the catalysts. We found that IL [Bmim]Br as the co-catalyst in the reaction, which catalysed by [acae-mim][Cl]-Cu can obtain a high selectivity of 62.58%. While [acae-py][Cl]-Cu as the catalyst, IL [Bmim]Cl would obtain a 68.82% selectivity.At last, after all these researches, ILs were finally proved to promote the reaction on the improvement of catalytical activity and selectivity. It was the effect of the whole IL co-catalyst, but not only the effect of individual anion or cation.