D-Excess-LaA Production Directly from Biomass by Trivalent Yttrium Species
Shuguang Xu,
Jing Li,
Jianmei Li,
Yi Wu,
Yuan Xiao,
Changwei Hu
Affiliations
Shuguang Xu
Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, PR China
Jing Li
Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, PR China
Jianmei Li
Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, PR China; Corresponding author
Yi Wu
Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, PR China
Yuan Xiao
Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, PR China
Changwei Hu
Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, PR China; Corresponding author
Summary: D-lactic acid (D-LaA) synthesis directly from actual biomass via chemocatalytic conversion has shown high potential for satisfying its enormous demand in widespread applications. Here we report yttrium (Y(III))-species-catalyzed conversion of xylose and raw lignocelluloses to LaA with the highest yield of 87.3% (20% ee to D-LaA, ee%=(moles of D-LaA - moles of L-LaA)/(moles of D-LaA + moles of L-LaA) × 100). Combining experiments with theoretical modeling, we reveal that [Y(OH)2(H2O)2]+ is the possible catalytically active species, enabling the unconventional cleavage of C3-C4 in xylulose and the subsequent dehydration of glyceraldehyde to pyruvaldehyde (PRA). The distinct interactions between hydrated-PRA and [Y(OH)2(H2O)2]+ species contribute to the formation of different enantiomers, wherein H-migration via re-face attack leads to L-LaA and that via si-face attack yields D-LaA. The lower strain energy barrier is the origin of excess D-enantiomer formation. : Chemistry; Catalysis; Biomaterials Subject Areas: Chemistry, Catalysis, Biomaterials
