title: Hetropolyacid-Catalyzed Oxidation of Glycerol into Lactic Acid under Mild Base-Free Conditions.
abstract: Lactic acid (LA) is a versatile platform molecule owing to the opportunity to transform this compound into useful chemicals and materials. Therefore, efficient production of LA based on inexpensive renewable feedstocks is of utmost importance for insuring its market availability. Herein, we report the efficient conversion of glycerol into LA catalyzed by heteropolyacids (HPAs) under mild base-free conditions. The catalytic performance of molecular HPAs appears to correlate with their redox potential and Brønsted acidity. Namely, H3 PMo(12)O(40) (HPMo) exhibits the best selectivity towards LA (90 %) with 88 % conversion of glycerol. Loading of HPMo onto a carbon support (HPMo/C) further improves LA productivity resulting in 94 % selectivity at 98 % conversion under optimized reaction conditions. The reaction takes place through the formation of dihydroxyacetone/glyceraldehyde and pyruvaldehyde as intermediates. No leaching of HPMo was observed under the applied reaction conditions and HPMo/C could be recycled 5 times without significant loss of activity.
authors.affiliation: Key Lab of Polyoxometalate Science of Ministry of Education, Northeast Normal University, Changchun, 130024, P. R. China.
authors.forename: Meilin
authors.initials: M
authors.lastname: Tao
authors.affiliation: Key Lab of Polyoxometalate Science of Ministry of Education, Northeast Normal University, Changchun, 130024, P. R. China.|Chair of Heterogeneous Catalysis and Chemical Technology, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany.
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Yi
authors.affiliation: Chair of Heterogeneous Catalysis and Chemical Technology, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany.
authors.forename: Irina
authors.initials: I
authors.lastname: Delidovich
authors.affiliation: Chair of Heterogeneous Catalysis and Chemical Technology, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany. Palkovits@itmc.rwth-aachen.de.
authors.forename: Regina
authors.initials: R
authors.lastname: Palkovits
authors.affiliation: Wood Material Science and Engineering Key Laboratory of Jilin Province, Beihua University, Jilin, 132013, P. R. China. bhsjy64@163.com.
authors.forename: Junyou
authors.initials: J
authors.lastname: Shi
authors.affiliation: Key Lab of Polyoxometalate Science of Ministry of Education, Northeast Normal University, Changchun, 130024, P. R. China. wangxh665@nenu.edu.cn.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
mesh_terms: D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D005990:Glycerol / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D019344:Lactic Acid; D002244:Carbon; D005990:Glycerol
keywords: base-free; glycerol oxidation; heterogeneous catalysis; heteropolyacids; lactic acid