Coordinating the ratio of Bronsted to Lewis acid sites in zeolite catalyst is crucial for the efficient conversion of dihydroxyacetone(DHA)to methyl lactate(ML)in methanol media due to the different acidic requirement...Coordinating the ratio of Bronsted to Lewis acid sites in zeolite catalyst is crucial for the efficient conversion of dihydroxyacetone(DHA)to methyl lactate(ML)in methanol media due to the different acidic requirements of the four fundamental reactions.Herein,we couple Sn-MFI and TS-1 zeolites with different abilities to induce methanol dissociation to rationally regulate the ratio of Bronsted and Lewis acid sites in methanol,thus facilitating the yield of DHA to ML.It is found that framework Sn sites with low dissociation energy(39.2 kJ/mol)induce methanol to release hydrogen protons,creating Bronsted acid sites to enable DHA dehydration to PA.Ti sites in TS-1 zeolite possess high methanol dissociation energy(73.5 kJ/mol),maintaining Lewis acidity in methanol,which provides sufficient active sites for cooperatively intensifying PA addition to HA and subsequent HA isomerization to ML.The synergistic effect of the two zeolites mitigates the side reaction while achieving high DHA conversion,thus steering the reaction toward ML generation.Consequently,ML yield increases by over 25% compared with that of single Sn-MFI zeolite,which offers a promising pathway to promote the synthesis of DHA to ML under mild conditions.展开更多
基金the SINOPEC Project(411058,413025)the National Key R&D Program of China(2017YFB0306800)the National Natural Science Foundation of China(21808244,22278441,and 22478452)for funding this research.
文摘Coordinating the ratio of Bronsted to Lewis acid sites in zeolite catalyst is crucial for the efficient conversion of dihydroxyacetone(DHA)to methyl lactate(ML)in methanol media due to the different acidic requirements of the four fundamental reactions.Herein,we couple Sn-MFI and TS-1 zeolites with different abilities to induce methanol dissociation to rationally regulate the ratio of Bronsted and Lewis acid sites in methanol,thus facilitating the yield of DHA to ML.It is found that framework Sn sites with low dissociation energy(39.2 kJ/mol)induce methanol to release hydrogen protons,creating Bronsted acid sites to enable DHA dehydration to PA.Ti sites in TS-1 zeolite possess high methanol dissociation energy(73.5 kJ/mol),maintaining Lewis acidity in methanol,which provides sufficient active sites for cooperatively intensifying PA addition to HA and subsequent HA isomerization to ML.The synergistic effect of the two zeolites mitigates the side reaction while achieving high DHA conversion,thus steering the reaction toward ML generation.Consequently,ML yield increases by over 25% compared with that of single Sn-MFI zeolite,which offers a promising pathway to promote the synthesis of DHA to ML under mild conditions.
