Mg(OH)2-Facilitated Liquid-Phase Conversion of Lactic Acid into 1,2-Propanediol over Cu: An Experimental and Theoretical Study

Abstract

Mg(OH)2 is found to exhibit superior performance in the liquid-phase conversion of lactic acid (LA) into 1,2-propanediol over Cu. A conversion of 90 % with a selectivity of 98 % is achieved at 513 K and 5 MPa H2. Mg(LA)2 could be identified as a crucial intermediate in this reaction, as it undergoes faster conversion than the combination of LA and Mg(OH2) and regeneration of Mg(OH)2 through the conversion of Mg(LA)2 as a substrate. DFT calculations reveal that the energetic span of the reaction decreases from 46.6 kcal mol−1 catalyzed with no cation to 43.6 kcal mol−1 with [Mg(OH)]+, confirming the facilitating effect of Mg(OH)2.