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Solid superacid SO42--S2O82-/SnO2-Nd2O3-catalyzed esterification of a-aromatic amino acids
| First Author: |
Zhu, CH |
| Abstract: |
alpha-Aromatic amino acid esters are important platform compound for drugs, sweeteners and fluorescent sensors. Due to the amphoteric dissociation and steric effect, the esterification of alpha-aromatic amino acids is difficult. Here, a green and efficient solid superacid, SO42--S2O82- /SnO2-Nd2O3 (SSSN), was synthesized and firstly used for the methyl esterification of alpha-aromatic L-tyrosine and L-tryptophan. The methyl esters yield was optimized with the highest L-TyrOMe yield of 93.1% and L-TrpOMe yield of 92% over SSSN-650 (SO42--S2O82- /SnO2-Nd2O3 calcined under 65 ?). Furthermore, it was clarified that the doping of Nd enhanced the electron-withdrawing inductive effect of SO42--S2O82- with increased Bronsted and Lewis acidity, which were beneficial to the esterification of L-tyrosine and L-tryptophan. Besides, Nd-doping reduced the activation energy during L-Tyr esterification by kinetics study. Finally, SSSN-650 could be recycled six times with > 70% of their initial ester yield. The decrease of catalyst activity was caused by carbon deposition and species leaching. This work launched a novelty, rapid and environmental-benign technology for the esterification of alpha-aromatic amino acid using solid superacid. |
| Contact the author: |
Zhu, WC; Zou, ZY |
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| Subject: |
Chemistry, Physical |
| Impact Factor: |
4.6 |
| Authors units: |
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| PubYear: |
2023 |
| Volume: |
535 |
| Publication Name: |
MOLECULAR CATALYSIS |
| The full text link: |
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