Li Zhi's research group at the School of Material Science and Technology, Shanghai University of Science and Technology has developed a catalytic substitution reaction that can be widely applied to compounds such as oils, sugar alcohol esters, and amino alcohol esters. , Provides a new direction for the catalytic conversion of renewable biomass. In addition, the method can simply and efficiently degrade polyester plastic PET into dicarboxylic acid monomers, providing a new way for the chemical recycling of PET. Related research results were published online in "Nature-Communication".
With the depletion of fossil energy and the worsening of the global environment, the development and utilization of renewable energy and resources is the only way for human existence. Among them, biodiesel that can be produced from natural animal and vegetable oils, waste cooking oils, and other fats and oils has received widespread attention in recent years because of its high performance, low cost, renewable, and direct mixing with ordinary diesel.
In order to avoid the production of crude glycerin from the source, Li Zhi's group first proposed a plan for direct functionalization of oils and fats and then transesterification. The crude glycerin was converted into other structures through catalytic reactions before production, with a view to improving biological The value of diesel by-products.
The researchers used a strong Lewis acid catalyst based on scandium, hafnium and other metal trifluoromethanesulfonates to activate the CO bond of the ester group, and utilized the neighboring group participation effect between the three ester group functional groups in the oil molecule to achieve For the selective nucleophilic substitution reaction of nucleophilic reagent on the primary alkyl CO bond in triglyceride, biodiesel precursor fatty acid and amino alcohol compounds with higher subsequent conversion value were obtained, and passed the gram scale experiment The practicality of this reaction is proved.
At the same time, the researchers also combined this research with the problem of waste plastic recycling and processing, using commercially available PET mineral water bottle fragments as raw materials, and replacing the repeated glycol ester units in PET through the action of saccharin and a small amount of catalyst. After hydrolysis and acidification, the polyester can be completely degraded into its monomeric terephthalic acid and by-product sulfonamide ethanol. This method is expected to form a new breakthrough and open up new research directions in chemical degradation and monomer recovery of waste plastics such as polyester. (Reporter Huang Xin)
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