The exploration of potential application of glycerol is of particular importance for solving the oversupply of glycerol as an unavoidable byproduct of biodiesel and affording profitable possibilities for sustainable biodiesel. Herein, we developed a simple, cheap but robust CuMg catalyst, which exhibited outstanding catalytic activity for the selective conversion of glycerol towards valuable glycolic acid, eliminating the addition of extra inorganic base. As high as 71.8% yield of glycolic acid was achieved, the highest value to date as far as we know. In combination of experiment and DFT calculations, it was revealed that Cu, Mg species in catalyst enabled the relay catalysis for the cascade reactions in glycerol transformation. Cu species in catalyst dominated the first dehydrogenation reaction of glycerol to glyceraldehyde, which was promoted by Mg species. Mg species followed to catalyze the next cleavage of C2-C3 bond in glyceraldehyde to generate glycolaldehyde. The final oxidation of glycolaldehyde to glycolic acid was achieved by the catalysis of Cu species. This relay catalysis of CuMg catalyst significantly inhibited the formation of glyceric acid and lactic acid by-products, thereby enabling the selective generation of glycolic acid.

中文翻译：

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铜镁催化剂中继催化甘油高效转化为乙醇酸

探索甘油的潜在应用对于解决甘油作为生物柴油不可避免的副产品的供应过剩问题以及为可持续生物柴油提供盈利的可能性尤为重要。在此，我们开发了一种简单、廉价但坚固的 CuMg 催化剂，该催化剂在将甘油选择性转化为有价值的乙醇酸方面表现出出色的催化活性，无需添加额外的无机碱。乙醇酸收率高达 71.8%，是迄今为止已知的最高值。结合实验和DFT计算，发现催化剂中的Cu、Mg物质能够对甘油转化中的级联反应起到中继催化作用。催化剂中的Cu物种主导了甘油到甘油醛的第一次脱氢反应，而Mg物种促进了该反应。 Mg物种随后催化甘油醛中C2-C3键的下一次裂解，生成乙醇醛。乙醇醛最终氧化成乙醇酸是通过 Cu 物质的催化实现的。 CuMg催化剂的这种中继催化作用显着抑制了甘油酸和乳酸副产物的形成，从而能够选择性地生成乙醇酸。